Spirent Communications FLEX-T5300 Tech-X Flex (NG2) User Manual Tech X Flex Manual

Spirent Communications Inc Tech-X Flex (NG2) Tech X Flex Manual

Contents

User Manual Part 2

Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-16: IP and Video TestingThis section describes the suite of IP and video (IPTV) functions available on the unit. These tests are available over various interfaces on the unit, including the Wi-Fi and Ethernet interfaces, and modular interfaces such as MoCA. Not all tests are available for all interfaces; see the respective documentation for specific testing support.Once an interface is correctly configured with routable IP information, testing from that interface should be generally identical to any other. For example, ping testing from the Wi-Fi interface should be identical to ping testing from the Ethernet interface, except that it is launched from a different menu. Therefore, the information is consolidated here and applies generally to any interface that supports the respective test.To configure an interface with routable IP information, use the IP Network Setup function (see IP Network Setup on page 6-1). Once setup is successful, the IP testing becomes available, depending upon unit licensing and the test support of the respective interface:NOTE: Your unit may or may not include all the functionality described in this section, dependent upon your licensing agreement with Spirent. Contact an account manager for more information.6.1 IP Network SetupThis function is used to configure the active interface as necessary to join an IP network. For example, if you are using the 10/100/1G menu, this function configures the 10/100/1G interface with the IP routing information required to send and receive IP traffic. For any interface, IP Network Setup is a required prerequisite to any test that sends and/or receives IP data over that interface.IP Network Setup must be performed each time the unit is started up, for the interface(s) that you intend to use. Furthermore, you may need to run the setup again after switching test menus, if the menu change activates a different interface on the unit. To facilitate frequent setup actions, the unit supports DHCP, which is the preferred method of configuration if a DHCP server is available. By using DHCP, you can more easily assure that valid IP routing information is assigned which does not conflict with any other host on the network.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-2Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsBefore attempting IP Network Setup, the unit must be linked up with the proper access device, according to interface type. For example, if you are performing 10/100/1G testing, the unit should be connected to a switch or router with an Ethernet cable. Or, for Wi-Fi testing, the unit should be within range and synchronized with an active Wi-Fi node.Note the following:• For DHCP, If you change the active interface, the unit will attempt to release the IP address from the DHCP server. For example, if you obtain an IP address through the Wi-Fi menu, then switch to the 10/100/1G menu, the IP address will be released.• If you disconnect the unit and reconnect it to another network, you should rerun the network setup. IP information for one network may not be routable on another.6.1.1 Setup - IP Network SetupTable 6-1 IP Network Setup - Setup parametersParameter DescriptionType Method for assigning IP information:•Static - Static assignment. If you select this method, the unit will request the static address information.•DHCP - DHCP assignment. If a DHCP server is available, all IP information is assigned automatically. DHCP is a common method for IP address assignment within a home network and most home network routers include a DHCP server.NOTE: If the unit fails to get an address with DHCP, see Results - IP Network Setup on page 6-3.Option 60(DHCP only)Class identifier, used for the “option 60” field of the DHCP request as defined by RFC 1533. The class identifier may be used to send vendor or site-specific information for use by the DHCP server. If this field is not specified, no value is sent.NOTE: Dependent upon licensing, the dropdown list may include one or more commonly-used IDs.VLAN ID(Certain interfaces only)802.1ad VLAN tag for all transmitted Ethernet frames, from 1 to 4094. If unspecified, all transmitted frames are untagged. Note that:• This specification must match the requirements of the connected network; for example, a far-end port that is expecting a certain tag is likely to reject any traffic from the unit that is untagged, and vice-versa.• Some IP interfaces, such as the Admin Port, do not support VLAN tagging. In this case, the VLAN ID field does not appear.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-3IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsIf you select static assignment, the unit requires you to manually enter the IP address, subnet mask, default gateway, and DNS server. The unit will accept any information that you specify and attempt to use it for active test traffic, whether it is routable or not. Therefore, you should be sure to enter valid information, otherwise subsequent IP-based testing will fail. In addition, note the following:• Ensure that you have specified generally valid IP information. For example, the unit cannot assign an address of 0.0.0.0 because it is not valid for IP communications.• For static assignment, the DNS server address is optional. However, if you do not specify a valid server, you must know the target IP address for any IP-based tests. That is, the unit will be unable to resolve domain names such as www.spirent.com.6.1.2 Results - IP Network SetupThe results screen displays either the assigned IP information, or a failure message if the process failed. Fields include:Table 6-2 IP Network Setup - ResultsVLAN Priority(Certain interfaces only)If a VLAN ID is specified, the priority to assign with the tag.Parameter DescriptionResult DescriptionType Method used for address assignment, such as DHCP.IP AddressMaskGatewayIP information assigned to the respective interface.DNS1DNS2DNS address(es) assigned to the interface, for URL lookup. DNS2 only applies to DHCP transactions where the server returns a second DNS address. In any other case, this field shows N/A.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-4Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 6-1 Successful IP Network Setup6.1.3 DHCP troubleshooting tipsIf a DHCP operation fails, check the following:• The unit is properly connected to an active, networked device. For example, when using the 10/100/1G interface, the Ethernet cable must be properly connected. Or, for the Wi-Fi interface, the unit must be within range of an active wireless node.• The target network has an active DHCP server. In a home network, the DHCP server is normally incorporated with the home router, in which case you may need to log into the router to ensure that the DHCP server has not been disabled. See the router documentation for more information.6.2 Connection InfoThis function reports the IP information that is currently assigned to the active interface and is identical to the results screen from a successful IP Network Setup. For more information, see Results - IP Network Setup on page 6-3.6.3 PingIP Ping is a basic connectivity test that verifies whether a specific IP address can be reached. It sends a set of ICMP echo requests to an IP address and reports whether replies are successfully received. The request is sent via the active interface of the unit and requires that routable IP information is assigned to that interface. For more information, see IP Network Setup on page 6-1.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-5IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs6.3.1 Setup - PingTable 6-3 Ping - Setup parameters6.3.2 Results - PingAlong with details about each individual ping request, the unit also reports the following summary information:Table 6-4 Ping - ResultsFigure 6-2 Successful Ping resultsParameter DescriptionDestination Target address for the ping request, either a dotted IP address or a URL if a DNS is available. For example:208.22.58.142www.google.comResult DescriptionPackets Sent Number of ping requests sent to the addressPackets Received Number of ping requests reported as successfully receivedPackets Lost Percentage of ping requests that were lost (Packets Sent - Packets Received)Approximate round trip time in millisecondsAverage time for a ping requests to reach its destination and then for the unit to receive the success reportPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-6Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs6.4 TracerouteProvides a standard ICMP or UDP traceroute function that runs three concurrent traceroute processes and reports every router “hop” along the path, up to 30 hops. The results provide a topological view of the route that packets are using to reach the destination.The request is sent via the active interface and requires that routable IP information is assigned to that interface. For more information, see IP Network Setup on page 6-1.6.4.1 Setup - Traceroute testTable 6-5 Traceroute - Setup parameters6.4.2 Results - Traceroute testThe unit reports the IP address of each sequential hop along the path to the target, along with the roundtrip time required for each hop to receive the probe packet and the unit to receive acknowledgment. Because three independent traceroute processes are run, three topology sets are presented. An asterisk appears if a time cannot be determined, such as a response timeout when a router cannot or will not return a response.Figure 6-3 Successful Traceroute resultsParameters DescriptionDestination Target address for the traceroute request, either a dotted IP address or a URL if a DNS is available. For example:208.22.58.142www.google.comPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-7IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs6.5 L4 Performance TestThe L4 Performance Test is useful to verify the availability of a certain bandwidth and to determine the maximum overall throughput. According to the test setup, it can run in either the upstream or downstream direction.The test uses iPerf 3.1 as the underlying technology, based in layer 4 (TCP or UDP). Therefore, the target endpoint must be a compliant iPerf 3.1 server. The unit first establishes a “control plane” connection with the server over TCP, then negotiates the testing setup. When primary testing begins, either the unit or the server initiates the requested number of streams to the other endpoint. Both endpoints analyze the traffic and maintain an identical set of results metrics. Once the primary testing is complete, the endpoints exchange results information and then terminate all connections.iPerf 3.1 is principally developed and maintained by third-party Energy Sciences Network (ESNet) / Lawrence Berkeley National Laboratory. For more information on ESNet and iPerf, visit http://software.es.net/iperf/.6.5.1 Setup - L4 Performance TestTable 6-6 L4 Performance Test - SetupParameter DescriptionDestination IP address or URL of the target iPerf server.Duration Length of time to run the primary testing segment, in seconds.TCP or UDP Specifies whether to use TCP or UDP encapsulation for the primary test streams. Typically, TCP is the preferred option.Streams Number of parallel TCP or UDP streams to initiate and maintain during the primary testing segment. For a downstream test, traffic streams are initiated by the server and received by the client, each stream on a unique destination port. For an upstream test, the unit initiates the streams, each on a unique source port.Port TCP port on which the server listens for client communications. All activity regarding the server occurs on this port; including all control plane negotiations and test stream activity.BW Maximum throughput to attempt, in Mbps. For TCP tests only, you can specify 0 (zero) to test at the maximum throughput possible.TCP Win Sz(TCP tests only)Window size to configure on the TCP interface of each endpoint, in bytes. Specify 0 (zero) to allow the interfaces to negotiate and use a size based on default interface settings.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-8Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 6-4 L4 Performance Test - Setup6.5.2 Results - L4 Performance TestThe following table describes the basic metrics produced by the test, noting the following behavior:• If the test is set up to produce interval results, a full set of results is produced for each interval, independently for each stream. Additionally, each interval produces a full set of results that reflects the composite of all streams.• At the end of the results, the test produces a similar of group of results that reflect the entire testing period. These results are produced from the perspective of the sender and from the receiver, if available. For example, a 2-stream test might produce the following rows:–S1 - Whole-test averages/totals for stream 1, from the perspective of the sender interface.–R1 - Whole-test averages/totals for stream 1, from the perspective of the receiver interface.–S2 and R2 - Whole test results for stream 2.–S_ALL and R_ALL - Whole test results for all streams combined.Report Interval Interval at which to report interim results, in seconds. Specify 0 (zero) to produce composite results at the end of the test only.Direction Test direction; that is, the direction of traffic flow, either Upstream or Downstream.Omit Number of initial seconds to exclude from results calculations, normally used to avoid the impact of the normal TCP slow start algorithm.Parameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-9IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsNote that In some cases, “S” and/or “R” results are not available and do not display. In most cases, server compatibility is the cause.Table 6-7 L4 Performance Test - ResultsResult DescriptionStream Stream number for the respective row, or ALL to indicate a composite of all streams.Interval Test interval for which the results apply, displayed in seconds. Results that apply to the entire test show an interval that spans from zero to the test duration.Xfer Total amount of TCP or UDP payload data transferred during the interval, in MB.BW Average bandwidth seen during the interval, in Mbps.Retr(TCP upstream test only)Amount of data that required retransmission, in bytes.CWND(TCP upstream test only)Congestion window size at the end of the interval in bytes, as maintained by the sender.Pkts(UDP test only)Total number of packets transmitted during the intervalJitter(UDP download test only)Average jitter measured during the interval, in msec.Lost(UDP test only)Total number of packets that did not reach the destination.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-10Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 6-5 L4 Performance Test - Results (Downstream TCP Test)6.6 Web BrowserNOTE: The web browser is a purchasable option. Please contact Spirent for more information.The Web Browser allows you to access web pages from the internet and view them on the screen. It may be especially useful for verifying that internet access is available, beyond a simple ping test. If a residential subscriber cannot view a web page but you can with the unit, you can normally conclude that the trouble exists with the subscriber’s web browser, computer, or home network configuration. It may also be used to verify that a DNS is available.The Web Browser is similar to a browser used on a desktop computer, except that the smaller screen may require more use of the scroll bars. Furthermore, aside from basic hyperlinks, most webpage controls may not work correctly. In some cases, complex pages with extensive internal scripting may not display correctly or at all, so it is recommended that you use simple, fast-loading web pages to perform tests. In summary, the browser is intended as a testing tool, not as a fully-functional interface to the internet.To access the Web Browser, the active interface must be configured with valid, routable IP information. For more information, see IP Network Setup on page 6-1.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-11IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs6.6.1 Setup - Web BrowserTable 6-8 Web Browser - Setup parametersFigure 6-6 Web Browser, showing the Google™ website6.7 Single Device PLTThe Single Device PLT (Packet Loss Test) runs a continuous series of ping tests to a single destination, maintaining and presenting a set of cumulative results as testing progresses. These results include the number of lost ping packets since the beginning of the test.NOTE: This test is a purchasable option. Please contact Spirent for more information.Parameters DescriptionURL Target address of the web page to load, either a dotted IP address or a URL if a DNS is available. For example:208.22.58.142www.google.comNote the following:• When entering a URL, case is unimportant because all characters are converted to lower case when the browser is launched.• The unit remembers the recent addresses you entered.• The dropdown list may automatically include one or more commonly-used websites.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-12Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs6.7.1 Setup - Single Device PLTThe setup requires only the Destination for the ping tests:Figure 6-7 Single Device PLT - SetupCAUTION: You should select the destination for this test carefully. Because it effectively sends a continuous stream of packets to a single host, it could be construed as a denial-of-service attack by a third party that does not welcome such traffic.6.7.2 Results - Single Device PLTThe test runs indefinitely until manually stopped. Results are reported at approximately 1-second intervals and are as follows:Table 6-9 Single Device PLT resultsMeasurement Description# Sent Total number of ping requests sent since the beginning of the test.# Recv The total number of ping requests that successfully received a reply, as of the end of the respective reporting interval.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-13IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 6-8 Single Device PLT - Results# Lost The total number of ping requests that have not yet received a reply, calculated as:# Sent - # ReceivedNote that this number may fluctuate up and down, as a reply may be received in one interval for a request sent in a previous interval. Therefore, at any given time during ongoing testing, this number does not necessary represent a count of positively lost packets, because some may still be in transit. Once a test is terminated, it will wait a standard amount of time for any lingering requests to be acknowledged and/or time out, so the count for the final interval will be an accurate count of loss for the entire test.% Lost The percent of packets lost since the beginning of the test, calculated as:# Lost / # Sent...using the cumulative counts for the respective interval only.MinAvgMaxThe minimum, average, and maximum roundtrip times since the beginning of the test, not necessarily for the respective interval. Because these counts represent the entire test, the following notes apply:•The Min value cannot ever increase from one interval to the next, because new minimums can only reduce the value.•The Max value follows a similar logic except that it cannot decrease.•The Avg value may fluctuate based on changing conditions during the testing process. The longer the test runs, the more likely this value will stabilize as the number of data points contributing to the calculations continues to increase.Measurement DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-14Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs6.8 ThroughputThe Throughput test calculates the maximum data rate to and from a specific endpoint, designed as a basic upstream/downstream capacity measurement. The target endpoint of the test must be a computer running a webserver application that is specifically configured for this test. For more information, see Throughput server setup on page 6-16.Note the following:• While running this test, keep in mind that throughput in any direction can never be greater than the slowest segment in the path. Therefore, for proper interpretation of results, you should have some awareness of which segment is expected to have the lowest throughput under normal conditions.• This test is based on a transfer of data over a TCP connection. TCP data rates may vary dynamically during the course of transmission; therefore, results between different file sizes and different tests may be inconsistent. In particular:– Large file sizes may indicate a higher data rate than smaller sizes, because the endpoints will have more time to optimize the TCP link.– TCP involves retransmissions of lost data, which can have a varying effect depending on what stage(s) of the file transfer that the retransmission(s) occur. For example, if loss occurs later in the transfer when the TCP window size may be allowing larger units of transfer, a retransmission will be more costly to the overall data rate.In summary, while this test may be useful for determining a baseline for the user experience, it cannot provide a precise or consistent data rate measurement at the lower data link layer.6.8.1 Setup - ThroughputThe setup screen requires the following parameters:Table 6-10 Throughput setup parametersMeasurement DescriptionServer IP address of a properly-configured throughput server running on port 80 (see Throughput server setup on page 6-16). A URL is also acceptable if a valid DNS was assigned during IP Network Setup (see IP Network Setup on page 6-1).Upload Size (kB)Download Size (kB)Total amount of data to send in each direction, up to 100,000 kilobytes each direction. For each direction, the test measures the amount of time required to send the respective amount of data and uses that measurement to calculate the overall data rate. Larger amounts of data facilitate greater accuracy but increase testing time and bandwidth consumption.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-15IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 6-9 Throughput - Setup6.8.2 Results - ThroughputThe test produces the following results:Table 6-11 Throughput resultsMeasurement DescriptionUpload RateDownload RateMaximum achievable data rates in both directions, averaged across the testing period.% Complete A progress counter that increments while the test is running, until it is 100% complete.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-16Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 6-10 Throughput - Results6.8.3 Throughput server setupThe Throughput test requires a testing destination that is specifically designed to recognize and process throughput exchanges with the unit. This destination must be an HTTP (web) server running on a networked computer and installed with Spirent-specific components. The following procedure is a broad overview of server installation and setup.NOTE: To accomplish this task successfully, a basic knowledge of web server administration and python scripting is recommended. For assistance with setup and troubleshooting, please contact Spirent.1. Download and install the web server - The supported web server is the Apache HTTP Server, available at the time of this writing at:http://httpd.apache.org/download.cgiYou should select the most recent stable (alpha) release for your platform (Windows, etc.). Install it using default parameters except for the requested web administrator email address, which you may want to change to the real address of an administrator (perhaps yourself). Note the following:• The server must be set to listen on port 80 for HTTP requests.• Depending on the platform and installation type, you may need to manually start the server following installation. See the Apache documentation for more information.2. Download and install an ActiveState python package - At the time of this writing, the latest stable python packages are available at:http://www.activestate.com/activepython/downloads/Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-17IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsDefault installation settings are recommended.3. Retrieve and install the Spirent python scripts - You must place two python scripts (*.py) files in the cgi-bin directory in the Apache installation area. These files are available from Spirent, normally from the corporate/customer FTP site at the following address:ftp.sab.spirentcom.comFor login credentials, please contact your account manager.6.9 SpeedtestThe Speedtest provides a standard internet-based maximum throughput test. By exchanging data with an internet endpoint, it attempts to determine the maximum data rate supported in both the uplink and downlink directions. Note that this test may put a temporary strain on the local network, as it is attempting to exchange the maximum amount of data possible.This test is a purchasable option. Please contact Spirent for more information.6.9.1 Setup - SpeedtestThe setup screen requires the following parameters:Important note: The python scripts are currently configured for Windows usage only and require that the system path environment variable contains the path to the python executable. If you are using Windows, you should ensure that this variable is set correctly.If you are using Linux or Unix instead, you must adjust the first line of each script to point to the location of the python interpreter, for example:#!/usr/bin/pythonIf the system is unable to locate the python interpreter based on this line, throughput testing will fail. For more information, see the operating system documentation, python documentation, and/or contact Spirent.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-18Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 6-12 Speedtest setup parametersFigure 6-11 Speedtest - Setup6.9.2 Results - SpeedtestNOTE: While the test is actively sending traffic, the screen presents a “collecting data” message and does not update further until the traffic exchange is complete. It may take up to a minute to complete this exchange, after which the final results are presented graphically.The test produces a simple graphical display of the maximum speeds achieved for upload and download.Measurement DescriptionRegion General location of the target endpoint. The options in the list represent designated endpoints that are specifically provided for this test. These locations, along with the underlying IP addresses, are hardcoded with the unit firmware. Normally, you should select the geographically closest location. For more information on these locations, contact a local administrator. For more information on augmenting this list, please contact Spirent.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-19IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 6-12 Speedtest - Results6.10 All Devices Packet Loss (Device Discovery)The All Devices Packet Loss test runs a series of ping tests to one or more IP hosts on the LAN, maintaining and presenting a set of cumulative results as testing progresses. Results are focused on the number of packets that are lost; that is, for which the unit never receives a reply. Note that:• Initially, the test automatically detects all IP hosts on the LAN and presents a list of addresses, from which you can select the specific hosts you want to target with the ping testing stage. Testing to all selected hosts occurs simultaneously.• This test is effectively the same as Device Discovery, which appears in some menus instead of All Devices Packet Loss. The naming difference is due to the likely intended purpose; that is, whether the test will be used to discover devices only or to continue with packet loss testing. Regardless of the source menu or test name, you can choose whether or not to continue with packet loss testing.• For any given host, the ping testing stage is similar to the single-target Packet Loss Test (see Single Device PLT on page 6-11).6.10.1 Setup - All Devices Packet LossWhen initiated, the test behaves differently according to the active interface:•Wi-Fi or 10/100 - The host detection stage starts immediately.•MoCA - The unit prompts you to select MOCA-specific options related to the BHR. For more information, see Special MoCA BHR considerations - All Devices Packet Loss on page 6-21.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-20Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFollowing host detection, some addresses may be automatically selected and some may not. You should ensure that the selection(s) are correct for the test, as well as select the testing Duration that applies to all target hosts.NOTE: At this point, if device detection was the only original purpose, you can review the results and safely cancel the packet loss portion of the test.Figure 6-13 All Devices Packet Loss - Setup following the host detection phaseThe duration may be selected from the list or entered manually, up to 60 seconds. Alternatively, you can select Continuous for a test that runs until manually stopped.6.10.2 Results - All Devices Packet LossThe test sends ping packets to all hosts simultaneously and reports a running total of packets sent and lost:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-21IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 6-14 All Devices Packet Loss - Results (Continuous test)6.10.3 Special MoCA BHR considerations - All Devices Packet LossOn a MoCA network, the test can run on a LAN with or without an active router (BHR). To support both scenarios, you must first select one of the following options when the test is launched with the MoCA interface active:Figure 6-15 All Devices Packet Loss - MoCA test mode prompt•Replacing BHR - With this mode, the unit assumes that no router is present and serves as a basic DHCP server. During the host detection stage, any active devices should receive a short-lease IP address, suitable for completing the remainder of testing.If this option is chosen, the unit produces a subsequent prompt for the BHR IP Address and the BHR Mask. These settings allow the unit to simulate the router and distribute IP addresses that will be routable on the normal BHR-hosted LAN. If you specify values that do not represent the normal LAN, Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-22Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specsa LAN host may receive an address that is not routable once a router is connected; however, testing may still succeed.Figure 6-16 All Devices Packet Loss - BHR IP parameters•BHR Present - This mode assumes that a router is functioning normally on the LAN and no DHCP server on the unit is required.After these options are resolved, the remainder of testing follows the normal host detection and ping testing stages. Note the following:• When the Replacing BHR option is selected, the unit assumes that the IP information provided will be used to configure the MoCA IP interface. For this reason, the IP Network Setup function is not a prerequisite to launch the All Devices Packet Loss test, unlike most other IP-related tests. If it has already been run, the unit will prompt you to drop the current IP configuration before proceeding with the All Devices Packet Loss test.•If the BHR Present option is chosen but IP Network Setup has not been run yet, a DHCP-based address assignment will occur automatically.• The concept of replacing the router only applies to the MoCA interface because the unit can connect to all LAN devices via a single coax, by nature of the MoCA environment. For a 10/100/1G network, the unit would require a separate port for each device.6.11 IP Video testingIP video testing support includes:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-23IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs• Subjective quality assessment of viewer experience• Comprehensive statistics on multimedia transport streams• Video channel change timesVideo testing support includes:• “Active” testing, where the test set emulates a multicast endpoint and performs all actions necessary to start and/or join the stream. Depending on the location of the test set, this type of testing can provide the most comprehensive view of the actual subscriber experience.• “Passive” testing, where the test set is connected between two existing endpoints and passively monitors the video traffic between them. Passive testing is supported for multicast and unicast streams.Briefly, unicast vs. multicast is defined as:•Unicast - A single stream between two specific endpoints. Unicast video is similar to any conversation between distinct IP hosts, which in this case normally represent a video server and a subscriber device such as an STB.•Multicast - A system designed to transport a single video stream to multiple endpoints, reducing the demands on network bandwidth due to redundant data. For more information, see About IP multicast on page 6-43.For any given interface, note that testing support may vary according to limitations specific to that interface. Where appropriate, this documentation notes those variations.Specific video functions include:•Video QoS (Quality of Service) on page 6-23•Change Channel on page 6-51•Channel Guide Settings on page 6-536.11.1 Video QoS (Quality of Service)NOTE: Video testing is a purchasable option. Please contact Spirent for more information.This test provides subjective no-reference quality scores and MDI calculations on a specific IPTV channel stream, along with a set of network parameters, picture frame statistics, and other transport stream information.For a single-ended, active test, the unit must emulate a video endpoint and initiate/join the stream, after which it performs the quality assessment on the traffic sent directly to it. Some interfaces, such as the 10/100/1G interface, provide a bridging/mirroring mechanism where the unit can be placed between two Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-24Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specsdevices and passively monitor an existing stream. For more information on how the passive bridging process works with the Ethernet interface, see Unit setup for passive testing on page 4-4.For more details on how the quality assessment works, see How the analysis works - An overview on page 6-45.NOTE: The analysis focuses primarily on the data captured from the MPEG transport stream. For more information about MPEG transport, see the information under Digital video concepts overview on page 6-39, including About MPEG transport on page 6-41.Setup - Video QoSNote the following:• For multicast testing, if the unit has an active channel guide, the display will first present a channel selection screen when the test setup is initiated. After channel selection, the normal setup screen will appear, with the certain parameters prepopulated, such as the IP address and port. The use of a channel guide, if available, is generally recommended. For more information, see Channel Guide Settings on page 6-53.• When you run a test, the input parameters are stored as defaults for the next test and persist between reboots. The defaults are stored separately for each interface that supports Video QoS testing. For example, the settings used for testing from the 10/100/1G interface would be stored separately from those used for the modular MoCA interface.Figure 6-17 Multicast Video QoS Setup - Page 1 (with a channel guide)Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-25IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsTable 6-13 Video QoS test - Setup parametersParameter DescriptionChannel NumChannel AbbrFor multicast video only, if a channel guide was used, the channel number and abbreviation that was selected in the previous screen. If no channel guide is active, these fields do not appear. For more information on channel guides, see About channel guides on page 6-53.Multicast Stream IP-or-Destination IP AddrIP address of the video stream. For multicast video, if you selected a channel from the channel guide, this field is automatically populated.The IP address specified must reflect the destination IP address for video stream packets; that is, the first address contained in the IP packet headers. For a multicast stream, this will be a multicast IP address, not an IP address of a host on the network under test. For a unicast stream, this must be the IP address of the destination device on the network, such as an STB. For a discussion on multicast packet addressing and transport versus unicast, see About IP multicast on page 6-43.Multicast Stream Port-or-Destination IP PortThe destination UDP port associated with packets that contain the stream under test. The unit determines which packets should be included in the audio/video quality measurement based on the destination IP address and destination UDP port pair. For multicast video, if you selected a channel from the channel guide, this field is automatically populated. As an option, you can select All Ports Open from the drop-down list which indicates to ignore the port and use the IP address exclusively for identifying video stream packets. In the case of unicast streams where packets are addressed to a network device such as an STB, it can be difficult to determine the UDP port(s) in use. Therefore, this option allows traffic analysis based on IP address alone. While the STB may be receiving some data that is not part of the video stream, it is likely that most traffic will be video data that qualifies for analysis.NOTE: For the most accurate results with the All Ports Open option, run the test once to discover the precise port number, then restart the test using that specific port.In summary:• This field indicates the logical port that the unit will monitor for video traffic, for the specified IP address.•The All Ports Open option is only applicable to measuring unicast streams (for example, video-on-demand) using passive mode. The option allows the unit to determine the destination UDP port of the packets containing the stream under test dynamically.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-26Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsDuration Duration of the test in seconds, or Continuous to run the test until manually stopped.Interval Interval at which to report a full set of current measurement results, applicable to continuous tests only.Encapsulation MethodEncapsulation type of the stream(s) under test.•RTP•UDPMeasurement MethodMeasurement method to use, which determines the type of data returned by the test. For more information, see About MOS and R-factor calculations on page 6-46 and MDI measurement overview on page 6-48.•VQM - See Video quality measurement (VQM) overview and additional results descriptions on page 6-45.•MDI - See MDI measurement overview on page 6-48.Note that this selection fundamentally changes the nature of the analysis and the results that are returned. For the results from a VQM test, see Results - Video QoS (VQM test) on page 6-31. For the results from an MDI test, see Results - Video QoS (MDI test) on page 6-30.IGMP Version Version of IGMP to use for multicast join/leave requests. This must reflect an IGMP type in use on the network where the request is made.Options include:•IGMPV1 - IGMP version 1•IGMPV2 - IGMP version 2•IGMPV3 - IGMP version 3Codec Video codec used for the stream under test.•MPEG2•MPEG4•H264Parameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-27IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsJitter Mode Type of jitter buffer emulation used.Options include:•FIXED - The jitter buffer uses a constant fixed delay. The jitter buffer is bounded by a nominal and maximum delay, where the nominal delay dictates the actual delay and the maximum delay dictates the maximum number of packets that can be stored in the jitter buffer.•ADAPTIVE - The jitter buffer is bounded by a minimum, nominal and maximum delay, where the minimum delay dictates the minimal accepted jitter buffer delay, nominal delay dictates the starting delay and the maximum delay dictates the maximum delay of the jitter buffer. The maximum number of packets that can be stored in the jitter buffer is a set fraction of the maximum delay. GOP Type Video coder group of pictures (GOP) structure, representing the frame sequence in use on the stream with respect to I, P, and B frames. This value is used only as a default if the actual frame types and GOP structure cannot be dynamically detected from the stream.Options include:•A - I-frames only, for example:III…I•B - One I-frame followed by P-frames, for example:IPPP...PIPPP...•C - One I-frame followed by P- and B-frames with two B-frames between each pair of anchor frames, for example:IBBPBBP...BBIBBP...•D - All P-frames, for example:PPPP...P•E - One I-frame followed by P- and B-frames with one B-frame between each pair of anchor pictures, for example:IBPBP...BIBP...For more information about MPEG pictures, see About IP multicast on page 6-43.Parameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-28Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsGOP Length Number of frames in a group of pictures (GOP) on the stream, related to the GOP type. This is essentially the I-frame update interval; that is, the number of frames from one I-frame to the next. This value is used only as a default if the actual frame types and GOP structure cannot be dynamically detected from the stream.Range:1 - 100Loss Sensitivity This defines how much the quality assessment should be sensitive towards packet loss and discards. A higher value indicates the video stream is more sensitive to packet loss/discard. When set higher, the calculation model will respond more rapidly to packet loss on the network under test, and packet loss will have a greater impact on the calculated score. If set lower, the results will be less affected by packet loss. This setting makes the analysis tunable for different varieties of encoders and various network environment conditions.Concealment Level This parameter defines the effectiveness of the packet loss concealment algorithm use by the encoder. A higher value indicates a better PLC algorithm. This setting helps compensate for reduced packet loss due to regeneration by technologies such as forward error correction (FEC). In other words, it affects how sensitive the quality assessment is to packet loss, with some similarity to the loss sensitivity setting. A higher setting indicates that overall packet loss will affect the quality score less. A setting of zero or none indicates no concealment, meaning that packet loss will have the most impact to video quality, with respect to this parameter's influence.Valid values are:0 to 50Complexity This parameter defines the video content coding factor. A higher value indicates the video stream can be encoded using a lower bit rate to achieve a given quality.Valid values are:-50 to 50Original Quality Original picture quality. This value represents the subjective quality of the video before encoding, which is the theoretical maximum that the quality ever could be after encoding, transport, and decoding.Valid values are:256 - 1280, proportional to the 1.0 to 5.0 MOS range, scaled by a factor of 256. For example, a value of 1242 is equivalent to a MOS of 4.85.Parameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-29IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsCoder Class Video coder class, which describes the ability of the stream to tolerate packet loss with respect to perceived quality. The coder class is determined by two contributing factors:• Codec - Some codecs, particularly older codecs, are very sensitive to packet loss and degrade very quickly with small amounts of loss.• Error correction and concealment - A number of loss mitigation techniques may be employed to conceal packet loss, typically involving coordination between the video server and client where checksum and other validation methods allow missing data to be supplemented.The specified value determines how heavily the analysis weights the effects of packet loss. For example, if you specify an operation at high rates of loss, any detected loss will have less of an effect on final quality scores. This is normally a static setting on any given network that does not change between tests.Valid values are:•A - Stream can operate over networks with up to 20% packet loss•B - Operation with up to 10% loss•C - Operation with up to 5% loss•D - Operation with up to 0.5% lossInternational Code Country/continent code, used to adjust quality scores based on cultural differences in different global regions. For example, subjective human testing using the same video stream have indicated that MOS scores in Japan are typically lower than those found in Europe and North America. It should be noted that this setting is purely subjective based on existing statistical data and cannot be assured to accurately represent any particular individual.Valid values are:•NA - North America•SA - South America•EU - Europe•AF - Africa•AS - Asia•JP - Japan•AUS - AustraliaParameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-30Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsResults - Video QoS (MDI test)Figure 6-18 Video QoS results - MDI testNominal Rate Payload media rate (audio and video) in kbps, used in calculating the MDI delay factor.Valid values are:0 - 20000, where 0 indicates auto-detection of rate.Parameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-31IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsResults - Video QoS (VQM test)Test results are presented in three different screens, each of which has two different pages. Use the appropriate function key to switch between screens. Note the following:• All quantitative measurements apply to the reporting period only. No measurements are cumulative.• Unless indicated otherwise, any reference to “packets” means MPEG packets, not IP packets.Result DescriptionIP AddressPortIP address and port of the media stream, specified at test launch.Receive Rate Speed of frames received, in kbits/sec. For VQM testing, this is the receive rate of the video or audio stream, as applicable. For MDI testing, this is the receive rate of the PCR stream.MDIMedia Loss RateDelay Factor (Avg)Delay Factor (Max)Delay Factor (Min)See MDI measurement overview on page 6-48.NOTE: The MDI result is colored green or red according to the fixed pass/fail thresholds shown in the Plot tab.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-32Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 6-14 Video QoS results - Summary results, Plot tabTable 6-15 Video QoS - Summary results, MOS tabResult DescriptionMOS graph Displays graph of calculated VMos, AMos, and A/VMos, which updates regularly for continuous tests. The graph assumes a fixed score of 4.0 as passing and 3.0 as marginal with coloring as follows:•Green - Passing (above 4.0)•Yellow - Marginal (between 3.0 and 4.0)•Red - Failing (below 3.0)The standards for any given architecture may differ. For more information on MOS scoring, see About MOS and R-factor calculations on page 6-46.Figure 6-19 VQM MOS graphResult DescriptionIP AddressPortIP address and port of the media stream, specified at test launch.V MOSA MOSA/V MOSSee About MOS and R-factor calculations on page 6-46.NOTE: Results are colored green or red according to the fixed pass/fail thresholds shown in the Plot tab.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-33IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsTable 6-16 Video QoS- Summary results, Stream/Expert Analysis tabTable 6-17 Video QoS - Stream results, Stream Metrics tabResult DescriptionCodec Type Stream type, as defined in ITU Spec ISO/IEC 13818-1.For valid values, see Table 6-24, Other recognized transport streams/PID types on page 6-38.Image Size Horizontal resolution, indicating the left-right size of the image, in pixels.-and-Vertical resolution, indicating the top-bottom size of the image, in pixels.Image Type Type of the image.Valid values are:•SDTV•HDTVDegradation from LossPercentage of the overall quality degradation that can be attributed to network packet loss.Degradation from JitterPercentage of the overall quality degradation that can be attributed to jitter buffer discards.Degradation from Codec TypePercentage of the overall quality degradation that can be attributed to video encoder/decoder selection.Degradation from DelayPercentage of the overall quality degradation that can be attributed to delay.Result DescriptionFrames Total number of frames received, by type.Lost Total number of packets lost containing data for the respective frame type; for example, the total number of packets lost containing I-frame data. These results are packet counts, not frame counts.NOTE: If packets for one frame type show an inordinate amount of loss compared to others, there may be a problem with network congestion and/or configuration. For example, some NEs may be configured to discard video B-frame data during periods of heavy congestion.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-34Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 6-18 Video QoS - Stream results, Stream Description tabDiscards Total number of packets discarded by the jitter buffer emulator containing data for the respective frame type; for example, the total number of packets discarded containing I-frame data. These results are packet counts, not frame counts.Impairments Total number of frames errored, by type. A frame is considered errored if a single packet containing data for it is lost or discarded.FEC Effect Calculated effectiveness of forward error correction (FEC) if it were applied to the stream. This value represents the potential effectiveness of applied FEC, not the effectiveness of previously-applied FEC.Opt FEC Blk Size Number of packets in an FEC block which is used when calculating the FEC effectiveness.Opt FEC Crct Pkts Number of correctable packets in an FEC block which is used when calculating the FEC effectiveness.Peak/Mean Rcv RateRatio of peak packet receive rate to the mean receive rate.Result DescriptionGOP Type GOP structure type of the stream. If the structure was detected by the analysis, this value represents the detected structure. Otherwise, it represents the default specified at test launch.For details on possible values, see Setup - Video QoS on page 6-24.GOP Length GOP length on the stream; that is, the total number pictures in a single GOP. If the structure was detected by the analysis, this value represents the detected structure. Otherwise, it represents the default specified at test launch.Receive Rate Speed of frames received, in kbits/sec. For VQM testing, this is the receive rate of the video or audio stream, as applicable. For MDI testing, this is the receive rate of the PCR stream.Peak Rcv Rate Peak speed of frames received, in kbits/sec. For VQM testing, this is the peak receive rate of the video stream. For MDI testing, this is the peak receive rate of the PCR stream.Result DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-35IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsTable 6-19 Video QoS - Stream results, Video Scores tabTable 6-20 Video QoS - Transport results, Stream Metrics tabResult DescriptionVSTQ Video service transmission quality. This is a codec-independent measure related to the ability of the bearer channel to support reliable video.Valid values are:0 - 100VSPQ Video Service Picture Quality. This is a codec-dependent measure of the subjective quality of the decoded video stream. It is equivalent to a V-MOS score, using a different scoring range.0 - 100Gap VSPQ Video Service Picture Quality during gap state periods. This is a codec-dependent measure of the subjective quality of the decoded video stream. It is equivalent to a V-MOS score, using a different scoring range.Burst VSPQ Video Service Picture Quality during burst state periods. This is a codec-dependent measure of the subjective quality of the decoded video stream. It is equivalent to a V-MOS score, using a different scoring range.VSMQ Video Service Multimedia Quality. This is a codec-dependent measure of the subjective quality of the decoded audio and video stream. It is equivalent to an AV-MOS score, using a different scoring range.Valid values are:0 - 100EPSNR Estimated average peak signal-to-noise ratio value for pictures in the stream, in dB. This value is derived based on other metrics and is not measured directly.Result DescriptionPackets Discarded Number of packets discarded. Packets may be discarded by the jitter buffer emulator for the following reasons, similar to an actual jitter buffer:• The buffer is too full to handle all incoming packets• A packet arrives too late to contribute to the media presentationOOS Packets Number of video/audio stream packets that arrived out of sequence, as detected by the jitter buffer emulator.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-36Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 6-21 Video QoS - Transport results, MPEG Stats tabBurst Loss Rate Average percentage of packets lost and/or discarded during burst periods.NOTE: For further information about bursts and gaps, see About gap and burst states on page 6-47.Burst Length Average burst period length in milliseconds.Gap Loss Rate Average percentage of packets lost and/or discarded during gap periods.Gap Length Average gap period length in milliseconds.Result DescriptionMPEG Sync Loss Number of times that the sync byte of a packet header was errored or not present for two consecutive transport stream packets.MPEG Sync Byte ErrNumber of times that a transport stream sync byte did not appear following a 188-byte, 204-byte, or 208-byte transport stream packet.MPEG Cont Err Number of times that the continuity count of a received packet did not increment by one, as compared to the previous packet. The continuity count is a 4-bit field in the packet header that increments from 0 - 15 for each transmitted packet, resetting at zero as necessary. Continuity count errors are normally caused by lost or out-of-sequence packets.NOTE: This result may be reported at different granularities. When reported at the transport stream PID level, it represents errors associated with packets assigned to that PID. When reported at the elementary stream level, it represents errors associated with packets for the respective elementary stream.MPEG Trnspt Err Number of packets that indicated a transport error, by means of the transport error bit in the packet header. The transport error bit is set to "1" when at least one uncorrectable bit error exists in the packet.NOTE: This result may be reported at different granularities. When reported at the transport stream PID level, it represents errors associated with packets assigned to that PID. When reported at the elementary stream level, it represents errors associated with packets for the respective elementary stream.Result DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-37IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsTable 6-22 Video QoS - Transport results, Jitter/Delay Stats tabNOTE: Not all stream types defined in ISO/IEC 13818-1 are supported. Any packets from unsupported types are discarded and excluded from all test results.Table 6-23 Supported stream types/namesPCR Repetition Err Number of times that the interval between PCR (program clock reference) transmissions exceeded 100 ms, if the discontinuity indicator is not set. The PCR is used as a time synchronization tool between the encoder and decoder. If the discontinuity indicator is not set, the encoder expects a 100 ms or smaller interval between PCRs. Both the PCR and discontinuity indicator are part of the packet header.PTS Err Number of times that the PTS (presentation time stamp) repetition period exceeded 700 milliseconds. A PTS is a part of the PES packet header and indicates the exact moment when a video frame or an audio frame has to be presented to the user. It is important for synchronization of the audio and video streams. Note that this parameter is always reported as NA for elementary streams that do not have presentation time stamps.Result DescriptionMAPDV The true average mean-absolute packet delay variation in milliseconds. This type of measurement is sometimes referred to as jitter.For more information on MAPDV, see About packet delay variation (PDV) on page 6-47.PPDV The packet-to-packet delay variation in milliseconds, according to a calculation model defined in RFC 3550.For more information on PPDV, see About packet-to-packet delay variation (PPDV) on page 6-48.Stream type value Stream type name2 or 128 MPEG-2 VIDEO3 MPEG-1 Layer II AUDIO4 MPEG-2 AUDIOResult DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-38Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 6-24 Other recognized transport streams/PID types5 MPEG-2 Private6 (with MPEG descriptor_tag 86) Teletype6 (with MPEG descriptor_tag 106)-or-129DOLBY AC-3 AUDIO11 DSM-CC15 MPEG-2 AAC AUDIO16 MPEG-4 VIDEO (Part 2)17 MPEG-4 AAC AUDIO27 MPEG-4 VIDEO (H.264)255 UNKNOWN STREAMName/abbrev. Stream typeECM Entitlement Control Messages represent private conditional access information that specifies control words and possibly other stream-specific parameters related to scrambling and/or other facets of access control. When the Conditional Access (CA) descriptor is found in the TS_program_map_section (table_id=0x02) as specified in ISO/IEC 13818-1), the CA_PID specifies packets containing program-related access information such as ECM's. Its presence as program information indicates that it is applicable to the entire program. Its presence as extended ES (Elementary Stream) information indicates it is applicable to the associated program element.EMM Entitlement Management Messages represent private conditional access information that specifies the authorization levels or the services of specific decoders. They may be addressed to single decoders or groups of decoders. When the CA descriptor is found in the CAT section (table_id=0x01) the CA_PID points to packets containing system-wide and/or access control management information such as EMMs.Stream type value Stream type namePreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-39IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsDigital video concepts overviewAbout basic video and audio compressionCompression techniques are vital to allow modern communication networks to handle the transmission of packetized digital video. For example, without compression, a video stream with pixelized image frames would require a large amount of data, far too much for efficient transport across networks to multiple subscribers.Video compression involves multiple stages, beginning with the removal of spatial similarities from individual frames using techniques similar to JPEG (Joint Photographic Experts Group) compression. Then, similarities between adjacent frames are determined and removed from the stream, using complex algorithms to reuse identical data that was already transmitted and to “predict” data where future changes can be estimated. These processes serve to reduce the two primary forms of redundancy:•Spatial redundancy - Within any given video frame, certain data may be redundant, such as large portions of the same color or geometrical design. In this situation, compression may be employed to represent portions of the frame as smaller mathematical values, rather than expressing every single pixel individually, when many pixels are the same.•Temporal redundancy - Adjacent video frames often have many similarities, especially with video of still or slow-moving objects. In this case, sequential frames may have redundant information expressed over time as the video is played.In the end, the encoders/decoders effectively form a system where the technology is able to interpolate redundant data, without the need to transmit it. This system allows for more efficient network capacity utilization when transporting audio/video streams over communications networks.Frame typesAs part of the reduction in redundancy, the video is compressed and reorganized into three different frame types, serving individual roles as follows:Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-40Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs•I-frames (or “Intra pictures”) - I-frames are coded without reference to other pictures. That is, they contain the full dataset required to render a video frame and do not interpolate based on references to other frames. Therefore, they may employ compression to reduce spatial redundancy, but cannot reduce temporal redundancy. I-frames are critically important for providing references to other frames and serve as access points in the bitstream where decoding can begin. Because other frame types do reduce temporal redundancy based on a dependence to the I-frames, the loss of I-frames in a video stream has the most significant impact.•P-frames (or “Predictive pictures”) - P-frames are interspersed between I-frames and allow a combination of spatial and temporal redundancy. They can use internal spatial coding like I-frames, but they can also derive data through references to previous I and P-frames. Through this referencing, a P-frame can render the picture without a full pixel-by-pixel dataset, using redundant information presented in preceding frames.•B-frames (or “Bi-directional predictive pictures”) - B-frames are a further extension of the P-frame predictive methodology, except that they may reference preceding and/or following I and/or P-frames. The use of B-frames allows the highest degree of picture quality with the most efficient compression. When a B-frame references a frame that comes after itself, the decoder must have received the referenced frame before the B-frame can be decoded, making the frame order different from the actual display order. Therefore, B-frames can cause a delay in the decoding process, because the decoder must buffer the input while reordering the frames for display. Of the three, the loss of a B-frame generally causes the least impact to picture quality.At the data level, a frame is divided into slices which represent horizontal sections of the frame. Each slice is further divided into macroblocks which represent rectangular sections of the slice. This organizational structure is the reason that digital video exhibits “rectangular” errors when data becomes corrupted, rather than the general fuzz and/or static caused by a poor analog signal. For example:• If macroblock data is missing or corrupted, the video typically shows rectangles of missing picture on the screen, amidst an otherwise clear picture. Likewise, if a whole slice can’t be rendered, a larger rectangular portion is missing.• If whole frame data is missing or corrupted, the video may freeze on certain pictures altogether, rendering the last known frame while waiting for new frame data.GOP typesFor any video stream, a set of frames is called a group of pictures or GOP, with the specific sequence known as the GOP structure. A common GOP structure would include one I-frame, followed by two B-frames, then followed by one P-frame, and so on, represented as “IBBPBBP…" The following figure represents a simplified diagram of frame reference and interpolation, using a typical GOP structure:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-41IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 6-20 Compressed video stream framesAudio compressionAudio compression has some similarity to video compression, in that techniques may be used to eliminate redundant data. Furthermore, audio exhibits the concept of “masking,” where one frequency may mask another and the human ear is unable to perceive it. Because it is unnecessary to transmit any data for sounds that will never be heard, the removal of this data from the original audio stream provides further possibilities for data reduction.Additional details of encoding, decoding, and compression algorithms are complex and beyond the scope of this document.About MPEG transportThe MPEG standards refer broadly to a set of protocols for transporting compressed audio/video programs over a communications network, such that a decoder can properly reconstruct the audio/video programs at the destination. It is overseen by the Moving Picture Experts Group (http://www.chiariglione.org/mpeg/).A fundamental concept of MPEG transport is the “program,” the higher-level entity that end users receive when they select a “channel.” Fully-decoded, an MPEG program is the entire dataset required to present a single multimedia experience to the user, such as the complete and synchronized audio/video streams required to watch a single IPTV channel.The preparation of the audio/video programs has two fundamental stages:I frames P frames B framesPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-42Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs•Elementary stream - The elementary stream is the basic compressed audio or video bitstream. In the case of a video stream, this is the original content segmented into macroblocks, slices, and frames, then packetized with header information required to reconstruct the stream at the far end. An elementary stream is a single stream of video or audio only, relying on the transport stream layer to associate it with other streams and create the concept of a program.•Transport stream - Once constructed, one or more elementary streams are packetized into a transport stream that provides all the instructions necessary to identify the data associated with a full program, synchronize with the encoder, and reconstruct and present the audio/video program properly. The transport stream includes the program clock reference or PCR, which provides the critical data required for the decoder to synchronize its internal clock with that of the encoder. Without synchronization, the decoder would be unable to recreate the video with the same timing as it was encoded. Furthermore, the transport stream includes information such as:–Packet identifiers or PIDs - Used as unique identifiers for individual elementary streams, as well as program-specific information as described below.–Program map table or PMT - Lists the elementary streams in the transport stream and identifies the respective program(s) to which they belong. A program includes one or more elementary streams, typically one video elementary stream and one or more audio elementary streams.–Program association table or PAT - Lists all the programs included in the transport stream, as a high-level list of all programs available to the decoder (or in other words, channels available to the end user). When a program is selected for decoding, the decoder uses the program identifier in the PAT to look up the required streams in the PMT.–Conditional access table or CAT - Includes pointers to the PIDs that contain the entitlement control/management messages needed to unscramble audio/video content, useful for subscription-based services where access is limited.Once completed, a transport stream is a sequence of 188-byte MPEG packets, ready for encapsulation and transport over a communications network. The header data of transport streams, as well as that of packetized elementary streams, is extremely useful for performing audio/video quality analysis, and therefore provides the great majority of data used to calculate quality scores and other metrics.With respect to degradation that may be caused during transport, the impact on audio/video quality depends heavily upon the specific portion of the transport stream that is affected. For example, at the lowest level, a loss of macroblock data may only cause a momentary anomaly in the display, perhaps not even perceptible by the viewer. At the other extreme, a loss of MPEG transport header data, such as a loss of synchronization, can cause the complete loss of the video altogether. For this reason, modern analysis techniques must carefully consider the nature of loss and its respective impact on quality.Overall, it should be noted that the descriptions here are highly-simplified, provided as a general overview only. The full architecture of a complete MPEG transport stream is multi-layered and very complex, beyond the scope of this document to describe.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-43IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsAbout IP multicastIP multicast is a set of protocols that allows a single IP packet to be sent to multiple hosts (that is, “group members”) without the need to send multiple redundant copies of the same packet from the source. It serves to alleviate network congestion when multiple hosts need to receive the same traffic, such as the case where multiple IPTV subscribers are watching the same channel and each will ultimately receive the exact same data payload.Consider the following diagram, which represents a small network without multicasting:Figure 6-21 Hypothetical network without group multicastingIn the previous figure, three subscribers are watching the same channel. The shaded packets represent the unicast IP streams required to deliver the service. The IP payload in each stream, however, is exactly the same, resulting in a redundancy that creates congestion and scalability issues.Alternatively, consider the following figure, which illustrates group multicasting:R2R3R1R4R5Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-44Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 6-22 Hypothetical multicast network with multicasting and IGMPIn this example, the routers are multicast-aware and can make intelligent decisions about packet forwarding. The routers control the forwarding of multicast packets, with those routers directly connected to multicast group members using Internet Group Management Protocol (IGMP) to manage the duplication and forwarding of packets to individual group members.In a multicast-enabled network, multicast routers interact and dynamically maintain a logical tree for routing multicast packets, in order to efficiently deliver the required packets to each subnet that requests them. If no subscribers on a particular subnet are members of a given multicast group (for example, no one on a particular subnet is viewing a particular audio/video stream), the network may automatically adjust to avoid multicasting that stream to that subnet. Similarly, when a host on a subnet successfully joins a group, the network will dynamically extend a branch of the respective multicast tree to the router serving the host. In summary, therefore, multicasting improves transport efficiency both by eliminating redundant packets from the same media source, and by eliminating the indiscriminate broadcast of any packets to branches in the network that have no hosts requesting them.Note that multicasting is a form of “selective broadcasting,” where packets from the source are simply duplicated as necessary and forwarded onto the respective links, all the way down the multicast tree to each requesting group member. IP multicast routers use specialized multicast routing protocols such as R2R3R1R4R5Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-45IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsProtocol Independent Multicast (PIM) to build logical multicast trees and forward packets efficiently between the multicast source and group members. Once multicast packets reach their destination subnets, group members "listening" for packets with the specific IP multicast (destination) address will receive and process the packets accordingly.The IP address range of 224.0.0.0 - 239.255.255.255 is reserved for multicast packets. It should be noted that these addresses are likely unroutable in a traditional sense on the destination subnets that receive the packets. Rather, it is the suite of multicasting protocols that allows packets to be properly forwarded and ultimately processed by the proper group member device(s). This is distinctly different from unicast transmission, where IP packets are addressed for a specific source/destination pair and exchanged exclusively between the two hosts.Video quality measurement (VQM) overview and additional results descriptionsThe following sections describe the quality measurement process in more detail, for the “VQM” mode of analysis. For more information on MDI, see MDI measurement overview on page 6-48.How the analysis works - An overviewThe following metrics may be used to estimate the overall subjective quality of the audio/video stream, some of which are also reported in the results:•Audio/video packet details - Comprehensive metrics describing the number of MPEG packets received, lost, and discarded.•General audio/video stream information - Stream characteristics such as audio/video codec, audio/video stream bit rate, video stream GOP size/structure, and video stream image size.•Degradation factors - Identification and quantification of the factors which have caused degradation of the video signal, such as codec, packet loss, and packets discarded due to buffer underrun and/or overrun.•General network metrics - Information on the overall packet transport network such as packet delay variation and packet loss.Quality is estimated based on general stream, packet, and frame characteristics that are known to have a predictable impact on user experience. This methodology provides reliable measurements without the need to decrypt a scrambled video signal. Packet loss is naturally the primary factor involved with audio/video quality degradation, but the following types of considerations also affect quality calculations:• Other problems related to network impairments, such as packet delay variation and out-of-sequence packets.• The inherent abilities of the codec and associated equipment to conceal network impairments such as packet loss.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-46Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs• The structure and length of GOPs (MPEG Groups of Pictures), especially with regards to the varied effects of packet loss on different frame types.• The bit rate and frame size (or resolution) used at the encoder, as smaller rates and lower resolutions can degrade the quality of the image even if transport is flawless.• The impact of recency. Recency is the trend of human viewers to judge audio/video quality to be lower immediately following a disturbance to the signal, and the subsequent trend for that perception to improve gradually if time passes with no further disturbance.• Packet loss distribution. Bursty packet loss events in which consecutive packets are dropped have a different effect on perceived audio/video quality than packet loss events in which single packets are dropped and the time (or “distance”) between the single loss events is significant.• Loss of synchronization between the audio and video signals.While it does not measure signal-to-noise directly, the analysis does use codec and packet loss/discard information to calculate an estimated peak signal/noise ratio (EPSNR). The EPSNR is then used as a key input for quality score calculations.About MOS and R-factor calculationsMOS (mean opinion score) is a numerical system used to grade the subjective perceptual quality of a multimedia (audio, video, or both) user experience. Originally based on ITU-T recommendations for the evaluation of voice quality, it uses a scale of 1 - 5 to indicate user experience with the following typical benchmarks:MOS scoring is frequently produced by software algorithms that monitor multimedia streams and attempt to “emulate” a subjective user experience. Such software is intended to produce results that are similar to MOS scores that would be recorded by actual human participants consuming and evaluating the media.Score Quality Human perception of degradation5Excellent Imperceptible. No degradation of quality can be detected by a human subject.4Good Perceptible. Degradation can detected, but does not adversely impact the user experience.3Fair Slightly annoying2Poor Annoying1Bad Very annoying or no data stream presentPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-47IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsThe R-factor is a similar concept and is actually the mathematical component by which a MOS is estimated. It is calculated using what is known as the “E-model” formula. This formula involves a subjective summation of impairment and “advantage” factors, including the typical packet network parameters such as jitter, latency, and loss. Like the MOS score, the higher the number, the better. An R-factor result is presented as a percentage, where 80% loosely corresponds with an MOS score of 4, and a factor of 50% corresponds with an MOS of 2.6.While these types of measurement may help you view a snapshot summary of network quality, you should remember that “real,” quantifiable network conditions are the only reliable means of judging network integrity. Any means of numerically calculating the quality of the human experience is necessarily subjective.About gap and burst statesThe software models the distribution of packet loss over the measurement duration, which allows for a more detailed characterization of the packet loss experienced by the audio/video stream. This is a four-state model in which two periods of loss exist, gap and burst periods, each of which has two states.The stream is considered to be in a gap condition of loss when consecutive packet loss is less than or equal to one packet. If two or more consecutive packets are lost, the stream is considered to be in a burst condition. Following the entry into a burst period, 128 consecutive packets must be received in order to return to the gap condition, a number determined though research of quality measurements. Note that the successfully received packets will be considered to have arrived during a gap period.Other test resultsAbout packet delay variation (PDV)Packet delay variation is a calculation based on the variation of a packet’s expected arrival time versus its actual arrival time. Each packet has its own PDV, which is determined by:| Expected time - Arrival time |...noting the use of absolute values. So, if a packet is expected to arrive at time1 but actually arrives at time2, it has a PDV of | time1 - time2 |. Typically, individual PDVs are used for calculating an average for multiple packets in a stream, or reporting the maximum PDV experienced during a measurement period.NOTE: Packet delay variation is sometimes referred to as jitter. However, the use of PDV terminology is preferred in this documentation due to its more specific definition.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-48Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsAbout packet-to-packet delay variation (PPDV)Packet-to-packet delay variation (PPDV) is a statistical calculation of delay variation, based on the method described by the IETF RFC 3550. It differs from basic packet delay variation (PDV) which looks at variations in arrival time overall, not necessarily variations between adjacent, sequential packets.As an example, consider four sequential packets, whose delays in arrival are 40, 42, 38, and 39 msec respectively. The delay variation of the second packet is 2 msec ( | 40 - 42 | ), the delay variation of the third packet is 4 msec, and so forth. The measurements continue for all selected packets in the measurement stream, with all measurements considered in the end for a calculation of statistical variance.Note that the usage of PDV versus PPDV is a complex subject and is beyond the scope of this document.MDI measurement overviewMedia delivery index (MDI), defined by IETF RFC 4445 (http://www.ietf.org/rfc/rfc4445.txt?number=4445), is a technique for evaluating the quality of media delivered over a packet-based network, including MPEG video. It focuses on the evaluation of delay variation and packet loss, which are the primary network impairments that impact the delivery of audio/video and other time-sensitive streaming media. In this respect, it is a packet-level, network-focused type of evaluation, different from the type of subjective quality analysis that monitors stream headers for specific transport characteristics. MDI may be used to evaluate voice, video, and other types of streaming media.An MDI result consists of two components: the Media Loss Rate (MLR) and the Delay Factor (DF), typically presented as:MLR:DFBefore analysis begins, the unit monitors the transport stream to determine the nominal media rate using the Program Clock Reference (PCR). The unit then monitors the transport stream for the entire testing interval to determine MLR and DF for that interval.The MLR is the count of lost or out-of-order media packets over the measurement interval. Every MPEG transport packet is counted, except for null packets (PID 0x1FFF) or packets with no payload. Note that a single IP packet may contain multiple media packets, so a single IP packet loss event may cause a significantly higher media loss.Because the analysis is not coordinated with the encoding source, the unit cannot know what media packets were actually sent. Therefore, it must determine lost packets using PID and continuity counter values from transport stream headers. That is, when a packet arrives, lost packets can be interpolated based on discrepancies between the current continuity counter and previous arrivals. Due to this method, Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-49IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsmeasured loss is only accurate when consecutive loss events are smaller than the capacity of the continuity counter, which is 0-15 (4 bits). In other words, the maximum amount of measurable consecutive loss is 15 packets. Also, note that a packet with an errored sync byte or a transport error indicator set will be discarded and considered lost for the purpose of this measurement.The unit also uses continuity counter values to determine out-of-order packets and the counter range of 0-15 provides a related accuracy limitation. The basic unit behavior is to consider any late packet that arrives within 7 packets of expected order as out-of-order, otherwise it is considered to be a member of the next counter “set.” This behavior is best illustrated by an example, as follows...Assume that all packets are arriving as expected, when packet 2 of a counter set goes missing (that is, packet 3 arrives after packet 1). At that point, packet 2 is initially considered lost. If packet 2 finally arrives sometime before packet 9, its status changes to out-of-order and the respective cumulative counts are adjusted accordingly. However, consider instead a scenario where packet 2 arrives after packet 10. In this case, the original packet 2 is considered permanently lost and the packet that arrives is considered to be packet 2 of the next set, at which point the originally-expected packets 11, 12, 13, 14, 15, 0, and 1 are initially considered lost. If these packets then arrive normally, their status changes to out-of-order and the respective counts are adjusted accordingly. When the “real” packet 2 arrives for the next set, the unit has two “packet 2’s” in the buffer and must assume that the original packet 2 is out-of-order for some unknown previous set, so it increments the out-of-order count again and resets the algorithm. In this scenario, a single late packet has caused the lost count to increment by one and the out-of-order count to increment by 8.The DF, presented as a quantity of time, is the maximum observed imbalance in stream flow over the measurement interval, with respect to the expected media payload rate. That is, it effectively reports how much buffering would be required to fully compensate for network delay variation at the respective node. As such, it also indicates the amount of latency that must be introduced in order to properly decode the stream. To calculate the DF, the software uses a “virtual buffer” concept, using the ingress of packets versus the expected “drain” rate (that is, the media rate) to determine the variance. In some respects, the DF provides a high-level view of the delay variation experienced by packets transiting from source to destination. It may be useful to quantify the performance of the audio/video streams and transport network over time and to adjust equipment buffers accordingly.For convenience, Spirent has implemented a proprietary algorithm to convert MLR and DF calculations into a score that resembles a mean opinion score (MOS), as defined by the ITU-T. This scoring method, referred to as “MDI-S,” uses a scale of 1 - 5 to indicate perceived viewer experience with the following typical benchmarks:Score Quality Human perception of degradation5Excellent Imperceptible. No degradation of video quality can be detected by a human viewer.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-50Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsAdditional video testing notesAbout the IP address specified for testingThe IP address specified must reflect the destination IP address for video stream packets; that is, the first address contained in the IP packet headers. For a multicast stream, this will be a multicast IP address, not an IP address of a host on the network under test. For a unicast stream, this must be the IP address of the destination device on the network, such as a set-top box (STB).About encrypted (scrambled) signals and frame type recognitionThe analysis software does not perform any decryption of scrambled signals. For monitoring a scrambled stream, this can affect the ability to recognize frame types because the type indicator data may be encrypted as well. Because perceived effect of packet loss varies widely according to the type of frame whose data was lost, the frame type is an important component when packet loss is evaluated. Therefore the software exhibits the following behavior with regards to frame type recognition:• If the signal is not scrambled, the software should be able to recognize frame types according to explicit data in the stream and precisely associate lost packets with the respective type.• If frame type data is encrypted but frame boundaries can be discerned, the software heuristically attempts to determine frame type based on relative data size and expected patterns.• If frames cannot determined at all, the software uses default GOP structure and length information specified when the analysis is launched to interpolate the probabilities of packet loss occurring within any given frame type. Over time, if the defaults accurately reflect the GOP setup of the stream, the measurements and estimations should be statistically correct.While the lack of decryption by the software may appear initially as a limitation, it actually provides much more flexibility with deployment and ease of maintenance. With the ability to interpolate encrypted frame types, users are not required to maintain and deploy decryption algorithms that require processing time, change periodically, and may be expensive and/or difficult to license.4Good Perceptible. Degradation can detected, but does not adversely impact the viewing experience.3Fair Slightly annoying2Poor Annoying1Bad Very annoying or no stream presentScore Quality Human perception of degradationPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-51IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs6.11.2 Change ChannelNOTE: Video testing is a purchasable option. Please contact Spirent for more information.The IPTV change channel test measures channel change time by measuring the time between IGMP requests and resulting changes in the packet stream. The unit accomplishes this measurement by joining a multicast stream and initiating an actual channel change, emulating the behavior of IPTV subscriber STB equipment.For more detailed information on the time calculation, see How channel change time is calculated on page 6-52.Setup - Change ChannelThe Change Channel setup differs whether or not a channel guide is active. For more information on channel guides, see About channel guides on page 6-53.With an active channel guide:The unit presents a table with which you can select the two channels for the test. All other required information is prepopulated from the channel guide, such as IP addresses and port numbers. For more information on how the channels are used, see How channel change time is calculated on page 6-52.Figure 6-23 Change Channel setup - Page 1 (with channel guide)NOTE: The screen has a small display area and can only show a limited number of channels from the guide at once. Remember to use the scroll bars on the table and/or the arrow keys on the key pad to locate the desired channels. Furthermore, be sure that the From Channel and To Channel at the bottom accurately reflect the channels you want to test.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-52Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsWithout an active channel guide:The unit requires you to manually enter the following information for each channel:•IP Address - IP address of the multicast stream•IP Port - UDP or TCP port of the stream, with respect to the Encapsulation Method•Encapsulation Method - Transport encapsulation used for the stream•Codec - Video codec typeResults - Change ChannelThe test reports the channel change time in msec, along with other parameters used in the calculation. For more information, see How channel change time is calculated on page 6-52.How channel change time is calculatedDuring a channel change test, the unit joins the first specified channel, leaves that channel, and then joins the second specified channel. During this process, four key events are used for the change time calculation, as illustrated in the following figure:Figure 6-24 Channel change calculation timelineReferring to this figure, if no time periods overlap, the basic formula for change time calculation is:Time = (LastA - ML) + (FirstB - MJ)MLMulticast join request - Ch. AFirst packet - Ch. AMulticast leave request - Ch. ALast packet - Ch. AMulticast join request - Ch. BFirst packet - Ch. BLastAMJFirstBTimeChannel A stream Channel B streamPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-53IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsIn these calculations, the individual terms are instances in time, not quantitative amounts of time. In other words, channel change time equals time it takes to leave the first stream plus the time it takes to join the second stream, measured from the respective IGMP requests.For reference, the unit indicates the following test results:•Leave to Last Time - Equals the (LastA - ML) term.•Join To First Time - Equals the (FirstB - MJ) term.6.11.3 Channel Guide SettingsThis function allows you to configure the unit for channel guide usage. It is available from multiple menus associated with active Video QoS testing, but the settings are global to all interfaces. For example, you can access and configure these settings from the 10/100/1G menu, but all changes will also apply to video testing on other interfaces, such as the modular MoCA interface. For more information about channel guides, see About channel guides on page 6-53.Table 6-25 Channel Guide Settings parametersAbout channel guidesA channel guide provides a shortcut for specifying IP video channels during video testing of multicast streams. When the unit joins and/or monitors a video stream for testing, it requires the IP address and port of that stream. If you do not have an active channel guide on the unit, you must enter the address and port manually. However, if you do have an active channel guide that includes the respective channel, it allows you to select a simple channel number or a more intuitive channel abbreviation, such as CNN or HBO. The unit then looks up the address and port in the guide instead of requiring a manual entry. A Parameters DescriptionUse Channel Guide Indicates whether a channel guide is currently active for video test setup. For more information, see About channel guides on page 6-53.Guide Name Name of the active channel guide, only applicable when Use Channel Guide=Yes. The drop-down list allows you to select from the guides currently on the unit, if any. If the list is blank, no channel guides have been imported. For more information, see About channel guides on page 6-53 and Download IPTV Channel Guide on page 5-8.Channel Format If Use Channel Guide=Yes, this setting determines how channels from the guide are initially sorted in a video test setup screen, either by number or abbreviation. In either case, the number or abbreviation comes directly from the guide.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-54Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specschannel guide also provides a series of other default testing parameters for each channel, such codec type and media stream information.NOTE: The channel guide concept does not apply to unicast video. With unicast, the destination IP address for video packets will be that of the endpoint device (such as an STB), rather than a predictable multicast address. Therefore, it is not possible to standardize unicast IP information within a channel guide.Channel guides are in XML format and must adhere exactly to the format in the following sample (except for the <!-- comments -->), with regard to tag names, case-sensitivity, and element hierarchy:<video-channel-info> <!-- Each channel is defined by a single <channel-info> element --> <channel-info> <!-- Channel number, an integer --> <channel-number>001</channel-number> <!-- Channel abbreviation, a string --> <channel-abbreviation>ESPN</channel-abbreviation> <!-- IP address of the channel stream in xxx.xxx.xxx.xxx format --> <IP-address>239.255.1.101</IP-address> <!-- UDP port of the stream, an integer --> <IP-port>3002</IP-port> <!-- Encapsulation type, UDP or RTP --> <encapsulation>UDP</encapsulation> <!-- Codec, H264, MPEG2, MPEG4, or NA --> <codec>MPEG2</codec> <!-- Jitter buffer mode, FIXED or ADAPTIVE --> <jitter-mode>FIXED</jitter-mode> <!-- GOP type, GOP_A, GOP_B, GOP_C, GOP_D, or GOP_E --> <gop-type>GOP_C</gop-type> <!-- GOP length, 1 - 100 --> <gop-length>15</gop-length> <!-- Loss sensitivity, -50 - 50 --> <loss-sensitivity>0</loss-sensitivity> <!-- Concealment level, 0 - 50 --> <packet-loss-concealment-level>2</packet-loss-concealment-level> <!-- Complexity (content coding factor), -50 - 50 --> <image-complexity>0</image-complexity> </channel-info> <!-- ...additional <channel-info> elements, one for each channel --></video-channel-info>Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-55IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsThe element names intuitively denote each respective parameter and the comments in the sample above provide some description of valid values. To ensure that a channel guide conforms to the required syntax, please contact Spirent for the latest XML schema and use it to validate your file(s).Importing channel guides to the unitSee Download IPTV Channel Guide on page 5-86.12 Packet CapturePacket Capture provides a basic packet capture utility, where traffic on an interface is recorded in PCAP format, then the PCAP file can be transferred from the unit for further analysis. This feature may be especially useful for VoD troubleshooting, as a capture can used to analyze the IGMP activity on the network.6.12.1 Packet Capture setup and launchPacket Capture requires the unit to be established as a traffic bridge, one of:•Ethernet-to-Ethernet - Two cables are connected at the 10/100/1G interface, where the internal switch is inherently bridging some traffic flow.•MoCA-to-MoCA - The unit is connected in standard MoCA “inline” mode (see Join MoCA Network In-Line (Bridging and passive testing) on page 7-19.•MoCA-to-Ethernet - The unit is connected in MoCA “ECB” mode (see About MoCA and 10/100/1G interface bridging (ECB) on page 7-23.The command to launch a capture is located in the VOD Scoring menu, which itself is located in the IP testing area for the respective interface (for example, 10/100/1G > VOD Scoring > Packet Capture.NOTE: Where applicable, capture data is retrieved from the WAN interface of the connection.The Packet Capture setup includes the following parameters:Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-56Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 6-26 Packet Capture - SetupParameter DescriptionMax Test Duration Maximum length of time to run the capture, in seconds. The actual time may be shorter if:• The maximum number of frames have been captured, or• The maximum capture file size is met (100 MBytes), or• The test is stopped while in progress.In all cases, a capture file is still produced for the length of time that the capture ran.Filter Expression Optional expression to filter traffic for the capture. The expression should use the “standard” PCAP format, described in detail at the following site:http://www.tcpdump.org/manpages/pcap-filter.7.htmlNote that this syntax may be complex and requires some expertise to apply properly.File Name Case-sensitive PCAP filename (minus the extension) that will appear in the Record Manager for upload, following the capture. The PCAP extension is appended automatically.Store pkt Length Maximum amount of each packet (Ethernet frame) to include in the capture, in bytes. Specify 0 (zero) to store every frame in its entirety. The overall valid range is 0 - 1499.Frame Count Maximum number of Ethernet frames to capture, after which the test stops automatically, where 0 indicates no limit. The overall valid range is 0 - 65535.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 6-57IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 6-25 Packet Capture - Setup6.12.2 Packet Capture results and PCAP file uploadResults include basic statistics about the amount of data captured. Afterwards, the capture file is available for upload using standard Record Manager tools (see Record Manager > Upload Files on page 5-4).Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 6-58Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-17: MoCA/RF - MoCA TestingThis section describes the MoCA-specific functions of the combined MoCA/RF module. The unit supports synchronization with MoCA standards 1.0, 1.1, and 2.0, with full backwards-compatibility behaviors as dictated by the respective standards. For a brief overview, see Overview of testing capabilities and setup on page 7-2.For more information on specific functions, see:•Join MoCA Network (Single-ended testing details) on page 7-4•Join MoCA Network In-Line (Bridging and passive testing) on page 7-19•MoCA Quick Test on page 7-23Figure 7-1 MoCA main testing menu7.1 Important notes on handling the moduleSee Handling the MoCA/RF module on page 2-30.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-2Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs7.2 Overview of testing capabilities and setupThe MoCA module allows the unit to join a MoCA network on a specified channel. After joining the network, the unit can perform functions such as:• Retrieval of statistics about itself and other nodes on the network, including the bandwidth between nodes.• IP address assignment and basic connectivity tests such as ping and traceroute.• Video testing, both by actively joining a multicast stream and by passively monitoring an existing stream.There are two basic physical setups for the unit:•Single-ended - A single cable terminated at the unit, where the unit is intended to join the network similar to any other node and perform stats retrieval and active testing functions (see Join MoCA Network (Single-ended testing details) on page 7-4)•Bridged - Two cables terminated at the unit, where the unit is “bridging” a MoCA connection and can passively monitor traffic, as well as perform active testing in either direction (see Join MoCA Network In-Line (Bridging and passive testing) on page 7-19)7.2.1 Testing scenariosThe following table describes certain issues that a technician might encounter, along with suggestions for how to use the unit for troubleshooting. Your use of the unit may vary according to field conditions and applicable protocol.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-3IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsIssue Troubleshooting suggestionsOne TV (using IPTV) in the home has a poor and/or intermittent picture, or no picture at allThe primary use of the unit is to confirm or rule out the STB as the cause. Troubleshooting might proceed as follows:1. Disconnect the cable from the STB, connect the unit directly to the STB, and attempt a single-ended MoCA synchronization on the LAN channel. This action effectively creates a small, independent MoCA network between the unit and the STB. The STB can be considered suspect if:• If the unit cannot synchronize at all• MoCA stats show poor bandwidth between the unit and STB, indicating partially functional but defective MoCA hardware within the STB2. If the previous step reveals no problems, connect the unit to the cable that originally fed the STB, then attempt a single-ended synchronization towards the home network (see Figure 7-4 on page 7-7). If synchronization is not possible or bandwidth between the unit and router is poor, consider a physical cause on the cable feeding the STB (see Common coaxial cable problems that affect MoCA on page 7-37).3. If the previous step reveals no problems, place the unit in-line with the STB and perform a passive video quality measurement while watching the poor video on the TV (see Figure 7-12 on page 7-19). If video quality measures poor, the problem is likely with the IPTV stream source upstream. If video quality measures OK, the STB may be suspect.All IP devices exhibit poor performanceIf the entire network is slow, the router, provider network terminal (NT), and/or associated coaxial cable may be suspect. A troubleshooting strategy may start with disconnecting the router and joining the LAN network at that point to check the bandwidth between nodes (see Figure 7-6 on page 7-9). If the WAN is also on the cable, it may be useful to join that network as well to check the bandwidth between the router and the NT. In all of these cases, the bandwidth reporting may help isolate problems with certain legs of the cable and perhaps splitter configurations that are causing degradation.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-4Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs7.3 Join MoCA Network (Single-ended testing details)(Select MoCA-RF > MoCA > Join MoCA Network)This command initializes the MoCA hardware and begins the process of joining the MoCA network on the specified frequency. If this command is successful, the unit has been properly admitted by the network coordinator (NC) and is prepared to conduct testing on the network.A single-ended setup allows the unit to operate on the network similar to any other single-channel MoCA device, such as an STB. The unit can be assigned an IP address, then send and receive traffic to and from other devices, as well as to and from the internet if connectivity is available.NOTE: The MoCA specifications allow five minutes for a MoCA network to stabilize and reach optimal performance. While the unit may not require a full five minutes to synchronize, the network may not be immediately ready for optimal testing.When attempting to join a network, it is important that you specify the correct frequency that corresponds to the desired MoCA channel, especially if a WAN and a LAN coexist on the same cable (see Example TVs work OK, but a wired Ethernet-connected computer in the house is slow or cannot connectIn this case, the MoCA/Ethernet bridge device or the computer itself may be cause. The first troubleshooting step is normally to replace the bridge device with the unit, configured to act as a bridge (see Figure 7-16 on page 7-23). If the computer operates properly afterwards, the bridge device is the problem, otherwise something is wrong with the computer or the cable that connects it to the bridge.Note that a misconfiguration of the bridge device can prevent it from operating correctly, such as improper MoCA channel and/or security information. To verify the MoCA channel information, the unit can be connected directly to the bridge device, then a single-ended MoCA synchronization performed to determine the channel in use.The MoCA network appears OK (that is, devices can synchronize), but no IP-based services are workingIf the network uses DHCP to assign IP addresses, synchronize with the LAN channel and do an IP Network Setup. If the unit cannot obtain an address, the router may be misconfigured or malfunctioning. If an IP address can be obtained, try to ping an internet address that you know should be available. If the ping fails, the problem may exist in the provider network upstream, not in the home.Issue Troubleshooting suggestionsPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-5IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsphysical MoCA network on page 7-32). If you intend to join the LAN network but instead join the WAN, certain testing may still work but the results may be misleading for troubleshooting efforts.Before attempting these functions, you should be familiar with the following:•Example physical MoCA network on page 7-32 - Describes the overall MoCA architecture, including information about how a LAN and WAN operate over coaxial cable.•Single-ended testing setup for STB troubleshooting on page 7-7 - Provides an illustration of connecting the unit at an STB location.•Single-ended testing setup for router troubleshooting on page 7-8 - Provides an illustration of connecting the unit at a router location.7.3.1 Join MoCA network setup parametersThe following input parameters are requested to join a network:NOTE: The unit will automatically synchronize at the MoCA version in use on the network, or if creating its own network, the highest version that the connected device will support. Therefore, no MoCA version input is required. However, different MoCA versions may use different frequencies.Table 7-1 Join MoCA Network - Input parametersParameter DescriptionFrequencyOffsetCenter frequency of the channel to join, along with an optional offset that may be applicable for some frequencies. Note that:• If you select a WAN frequency; that is, attempt to join the WAN, the unit should replace either the router or the ONT. A third WAN device on the network may cause unpredictable behavior.• Dependent upon licensing, different units may show different options in this field. For more information on why your unit(s) show any particular option, please contact Spirent.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-6Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 7-2 Join MoCA network - Input parametersSecurityPasswordSecurity information. If the network requires a password to join, enter that password and set Security to Enabled. Otherwise, set Security to Disabled and disregard the password.Dependent upon licensing, the behavior of these fields may vary, such as:• Some units may automatically disable security settings upon the selection of a certain Frequency, under the assumption that target networks will not have related security features enabled.• Under Password, some units may provide the option of Auto, allowing the unit to automatically attempt one or more preconfigured passwords. If your unit displays this option, please contact a network administrator or Spirent for more information on the password(s) that would be attempted.Bridge (ECB) modeEnables or disables ECB bridge functionality. If you plan to do video testing, specify Disabled. For more information, see About MoCA and 10/100/1G interface bridging (ECB) on page 7-23.NOTE: This feature will not function correctly if you have an active 10/100/1G Admin Port established. For more information, see Admin Port on page 5-5.Preferred NC If set to Yes, causes the unit to attempt to assume the role of network coordinator (NC) upon synchronization. Depending on network conditions and the behavior of other nodes, the unit may not be successful or may lose the NC role at some point afterwards.Parameter DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-7IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsOnce the unit has joined the MoCA network, the main statistics and testing menu becomes available:Figure 7-3 Join MoCA network - Main menuSingle-ended testing setup for STB troubleshootingWhen troubleshooting video issues, a common approach is to test at an STB location to rule out either the STB or the associated coaxial cable as the cause. Common options for connection include:•Replace the STB with the unit - In this scenario, the STB is disconnected and the unit is connected to the main coaxial network for synchronization. This type of configuration can be useful for statistics retrieval in an effort to isolate coaxial cable problems, as well as logical testing from the network perspective of the STB.•Connect directly to the STB - In this scenario, the unit and STB form a small, isolated MoCA network between themselves which allows the same statistics retrieval as any MoCA synchronization. If bandwidth between the devices is poor or synchronization cannot be achieved at all, a likely cause is defective MoCA hardware in the STB.Figure 7-4 Single-ended testing at an STB - Connection setupsTV/ STB (disconnected)Coax jack, connecting to other STBs, router, etc.- or -Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-8Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsNOTE: You must use the left port (port “A”) for all single-ended testing.Using a generalization of the example shown in Figure 7-21 on page 7-33, the leftmost configuration could effectively place the unit as follows:Figure 7-5 Emulating an STB - Network diagramSingle-ended testing setup for router troubleshootingWhen connecting at the router location, common options for connection include:Coax/MoCACoax splitterMoCA STBMoCA routerMoCA to EthernetCat 5 /EthernetPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-9IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs•Replace the router with the unit - In this scenario, the router is disconnected and the unit is connected to the coaxial network for synchronization. If both the provider WAN and residential LAN coexist on the same cable, this type of configuration may be useful for logical testing directly towards the WAN, perhaps to rule out the router as the cause for connectivity issues. Otherwise, it may be useful for general bandwidth-related troubleshooting. Note that if you disconnect the router, the LAN will be isolated from the provider network, and, if the router provides a DHCP service, no IP-based activity will be possible unless addresses are statically assigned.•Connect directly to the router - In this scenario, the unit and router form a small, isolated MoCA network between themselves which allows the same statistics retrieval as any MoCA synchronization. If bandwidth between the devices is poor or synchronization cannot be achieved at all, a likely cause is defective MoCA hardware in the router or possibly the cable used for the connection.Figure 7-6 Emulating a router - Possible connection setupsNote the following:• You must use the left port (port “A”) for all single-ended testing.• When connected directly to another MoCA node with a short cable, an attenuator may be necessary if the signal is too strong (or “hot”) for proper synchronization. Implementations may vary... please contact Spirent for recommendations.7.3.2 MoCA Network StatisticsMoCA Network Statistics provides access to a variety of statistics about the network with which the unit is synchronized, including packet counts, bandwidth, and bit-loading profiles. When initiated, the results are presented on several different pages:MoCA router (disconnected)Coax jack, connecting to STBs, possibly the NT, etc.- or -Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-10Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs•Bandwidth page (appears first) - Provides details on the available bandwidth between nodes on the network (see Bandwidth page (MoCA Network Statistics) on page 7-10)•MoCA Statistics page - Provides general information about the network, including details on Ethernet traffic (see MoCA Statistics page (MoCA Network Statistics) on page 7-11)•Node Stats page - Provides details on the links to every other node on the network, including bit-loading profiles (see Node Stats page (MoCA Network Statistics) on page 7-13)NOTE: When testing on a coaxial network that carries more than one MoCA network (such as a LAN and a WAN), it is very important that you have synchronized with the correct network. Otherwise, the statistics that you retrieve may be misleading. For example, WAN statistics will not show the same nodes as the LAN, because certain nodes only belong to one or the other despite the physical interconnectivity. For more information, see Example physical MoCA network on page 7-32.Bandwidth page (MoCA Network Statistics)The Bandwidth page provides a table of the bandwidths between all nodes on the network, including the unit. The table has a row and a column for each node in the network, with the “To” direction across the top. For example, consider the following table:Figure 7-7 Bandwidth pageThis table shows that the bandwidth from node 3 to node 0 is 241 Mbps, while the bandwidth from node 0 to node 3 is 204 Mbps, and so forth. While reviewing a Bandwidth page table, note the following:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-11IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs• The unit arranges the table with the worst performing link shown at the top left, with improving performance expanding towards the bottom right.• The top of the screen indicates which node represents the unit (node 9 in this example). In the table headings below, the network coordinator (NC) is indicated by an asterisk, which may or may not be the unit.• You can use the Display Version control to limit the table to nodes running a specific MoCA version.• Any result shaded in red or yellow has violated a configured threshold (see Thresholds on page 7-28).• Gray (blank) table cells appear for the following reasons:– When the cell would represent a link between a node and itself, which is not applicable.– When the cell represents a link between two external nodes (neither of which are the unit) and the network MoCA version is earlier than 1.1. Earlier versions of MoCA only support bandwidth statistic retrieval for links involving the node from which they were queried (in this case, the unit).– When the cell represents a link to or from a node that has been removed from the network, while bandwidth reporting was in progress. If a node is removed, the unit does not remove the row and column for that node; rather, it simply grays out any applicable cells.• On the touchscreen, you can press any row or column header cell to jump to the node statistics page for the respective node (see MoCA Statistics page (MoCA Network Statistics) on page 7-11).• Real-world bandwidths will vary from the theoretical maximums allowed by the MoCA standards. A lower bandwidth may indicate an issue with the physical network that is degrading performance, but may not necessarily prove that the bandwidth reduction is causing any problems itself. As long as the bandwidth is sufficient for the traffic that must traverse the respective link, a reduced bandwidth should not exhibit any visible problems with the network.Furthermore, the actual Ethernet bandwidth carried by a MoCA network is approximately 55% of the MoCA-level bandwidth. Therefore, a MoCA network must maintain nearly 200 Mbps for a fully-functional 100 Mbps Ethernet link.• The bandwidth between two nodes is typically asymmetrical, with a different rate for each direction. The difference is especially pronounced when the in/out polarity of splitters is reversed between directions.MoCA Statistics page (MoCA Network Statistics)The MoCA Statistics page provides general details of the overall network. Note that unless otherwise noted, results are cumulative since the time the unit joined the MoCA network. You can rest all counts to zero by using the Reset command (F3).Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-12Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 7-8 MoCA Statistics pageTable 7-2 MoCA Statistics descriptionsStatistic DescriptionFlex Node ID The node ID assigned to the unit by the network coordinator (NC). All devices receive a node ID from the NC upon admission.Flex MAC MAC address of the physical MoCA interface on the unit.Network CoordThe node ID of the NC device (see Example physical MoCA network on page 7-32).NOTE: On the Node Stats page, you can correlate a node ID with the MAC address of the actual device (see Node Stats page (MoCA Network Statistics) on page 7-13).RF Freq Frequency of the MoCA channel in use (see MoCA physical layer on page 7-36).Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-13IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsNode Stats page (MoCA Network Statistics)The Node Stats page provides an independent set of statistics for each node in the network, including the unit itself. Each node has its own tab, on which the Tx column represents the link from the unit to the respective node and the Rx column represents the link to the unit from the respective node. The first tab always represents the unit itself, with other tabs representing other nodes on the network. Note the following:Link ControlProbeAdmissionDetails on the count of frames received by and transmitted from the unit, according to frame type:•Tx - Frames transmitted from the unit, to any other node.•Tx Err - Frames transmitted that did not reach the destination and/or contained errors that could not be corrected by Reed-Solomon algorithms. These errors may indicate a problem with the physical cable that caused frame corruption or possibly a problem with the destination node(s).•Rx - Frames received by the unit, from any other node.•Rx Err - Frames received that contained uncorrectable errors. These errors normally indicate frame corruption that occurred during the transit over the coaxial cable.•Drop - Received frames that could not be processed due to insufficient buffer space (that is, too much traffic for the unit to handle) and/or frames that were expected to be received based on NC scheduling, but never arrived.Note the following:• For more information on how Link Control, Probe, and Admission frames operate on the network, see MoCA functional overview on page 7-35.• The mechanisms by which a MoCA network manages traffic as related to these frame counts is complex and beyond the scope of this document. See the respective MoCA specification for more details.Ethernet statisticsStatistics on the Ethernet frames received and transmitted by the unit carrying user data, such as IP video packets, as follows:•Packets - Number of frames sent to and received from any other node on the network•Dropped - Frames dropped due to insufficient buffer spaceThese measurements are taken at the Ethernet switch “behind” the MoCA interface, as frames transit from MoCA to standard Ethernet for internal processing. Note that these statistics are stored in 16-bit registers and therefore may roll over periodically.Statistic DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-14Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs• Another Tech-X Flex unit elsewhere on the network would appear as any other remote node for the purpose of these screens, except that the tab in the Node Stats page will include the prefix “FLEX”.• You can set these values to appear in red if specified thresholds are exceeded. For more information, see Thresholds on page 7-28.• Some of these results involve complex characteristics of a MoCA network which are beyond the scope of this document to describe. See the respective MoCA specification for more details.The first tab (for the unit itself) includes the following information:•MAC Vendor/Address - The vendor (Spirent) and MAC address of the unit MoCA interface.•Uptime - Amount of time since the initialization of the module. The module is initialized when a MoCA-specific function is launched, such as Join MoCA Network, not necessarily the same time that the MoCA menu is first accessed.•Link Uptime - Amount of time that the module has been synchronized on a the current network.•Reset Count - Number of times that the module has been resynchronized.•Network MoCA Version - The lowest version of the MoCA standard running on the network to which the unit is synchronized. For example, if a v1.1 node is present on the network, this field will report 1.1, even if the network includes other nodes using v2.0. For more information on multiple MoCA versions on a single network, see About multiple MoCA versions on a single network on page 7-38.•MoCA Versions Found - A list of all MoCA versions detected in use on the network.Figure 7-9 Node Stats page (Unit tab)All other tabs (for other network nodes) include the following information:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-15IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsTable 7-3 Node StatsStatistic DescriptionVendor/ MACMAC-layer address of the node’s MoCA interface and the vendor name associated with it. The unit attempts to determine the vendor by using a MAC address lookup table in the System menu area. If the vendor cannot be determined, it is reported as Unknown. For more information, see Vendor MAC Address on page 7-27.Node VersionHighest level of MoCA supported by the node, but not necessarily the version in use by the node. For more information, see About multiple MoCA versions on a single network on page 7-38.State State of the node, typically one of:•MAP Active - The node is actively participating on the network in a normal manner.•Idle - The node is recognized as a valid node but has entered a state of inactivity, such as a “sleep” mode. All bandwidth to and from the node will be reported as zero.Bit Rate The physical layer bit rates to and from the node (Tx and Rx) in Mbps, up to the theoretical MoCA maximum of the respective standard (see MoCA overview on page 7-31).CP-LEN(Cyclic Prefix Length)The size of the guard interval applied to MoCA symbols in each direction to protect the symbols from interference. Larger lengths reduce bit rates and thus reduce the bandwidth.Phase OffsetThe phase difference between the MoCA channel’s reference center frequency and the actual center frequency, in Hz. When phase offset increases, it diminishes the ability of a MoCA receiver to properly demodulate the channel subcarriers. Large values, such as 47000 or higher, lower the margin for interoperability.Log Gain MeanThe average amount of gain required to amplify the MoCA carriers received by the unit. A higher gain value corresponds with greater attenuation between the unit and the node under test. The valid range is 0-68 dB. Because this parameter applies to the behavior of the receiver, it always displays as N/A for the transmit direction.Power AdjustThe amount that the unit’s transmit power is reduced from reference power. A lower value indicates that more power is required and therefore corresponds with greater attenuation between the unit and the node under test. A larger number indicates more power reduction, therefore the larger the number, the “cooler” the signal and vice-versa. The range is 0-30 dB in multiples of 3 dB. Because this parameter applies to the behavior of the transmitter, it always displays as N/A for the receive direction.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-16Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 7-10 Node Stats page (Any node except the unit)The Node Stats page also includes links to bit-loading graphs which chart the number of bits that subcarrier frequencies are carrying (per symbol), across the MoCA channel in use. An active network continuously adjusts the number bits each symbol is expected to carry (that is, adjusts the QAM level), loading each subcarrier to the maximum amount that probe exchanges have determined is feasible for reliable transmission. Therefore, a bit-loading graph is essentially a granular view of channel bandwidth. If the coaxial cable has impairments which cause excessive attenuation, a bit-loading graph should show large trends of lower bit loading across the channel, causing a degradation of overall bandwidth.Each tab has two bit-loading graphs, one for transmitting from the unit to the respective node (Tx) and one for transmitting from that node to the unit (Rx). For the tab representing the unit itself, the graphs should be blank because transmission to itself is not applicable.A bit-loading graph presents all available subcarriers on the x-axis and plots the number of bits that each is carrying on the y-axis (8 bits maximum for 128-QAM, 10 bits for 1024-QAM, see MoCA physical layer on page 7-36). As a MoCA 1.1 example, the following graph shows an Rx link from Node 7 that is performing well. All subcarriers are carrying 6 or more bits per symbol:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-17IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 7-11 Bit-loading graphNote the following about bit-loading graphs:• The graphs indicate the center frequency of the MoCA channel with a red line. The bit-loading “notch” at this frequency is normal.• A bit-loading graph is not intended to provide information for precise troubleshooting of the MoCA physical layer. Rather, it intends to provide an overall view of trends in data capacity over the MoCA channel to help identify bandwidth issues between the applicable nodes.7.3.3 IP Network SetupIP Network Setup allows you to assign IP information to the active MoCA interface, which provides access to IP-based functions including video testing. The setup operates identically to IP Network Setup on other interfaces, such as the Wi-Fi and 10/100/1G interfaces. For more information, see IP Network Setup on page 6-1.Note that DHCP-based address assignment will only work if the unit is synchronized with a network that has an active DHCP server. In the case where the unit is in-line on a LAN network, a DCHP server is likely to be available on one side only (that is, the router side). If the unit is connected directly to an STB or similar device in a single-ended configuration, no DCHP server is likely to be available.7.3.4 IP Testing options over MoCAThe MoCA interface provides a suite of IP testing functions that are generally identical to their counterparts launched from other interfaces. The following table provides links to the central locations in this document that describe these tests in detail, along with any additional notes that may be relevant to the MoCA interface.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-18Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 7-4 IP testing options from the MoCA interface7.3.5 IP Video TestsOnce the MoCA interface is configured with valid IP information, the following IP video tests are available, assuming the availability or presence of an IP video stream:Test For more information Additional notesConnection Info Results - IP Network Setup on page 6-3This function reports the IP information that is currently assigned to the 10/100/1G interface and is identical to the results screen from any successful IP Network Setup.Device Discovery All Devices Packet Loss (Device Discovery) on page 6-19The Device Discovery test is the same test as All Devices Packet Loss, named differently because its likely purpose is to discover devices on the current subnet, which is the initial phase of the All Devices Packet Loss test. If desired, you can continue with the packet loss portion of the testing or cancel the test after the discovery phase.IP Video Tests IP Video testing on page 6-22 - - -L4 Performance Test L4 Performance Test on page 6-7- - -Packet Capture Packet Capture on page 6-55 - - -Ping Ping on page 6-4 - - -Single Device PLT Single Device PLT on page 6-11- - -Speed Test Speedtest on page 6-17 - - -Traceroute Traceroute on page 6-6 - - -Video QoS Video QoS (Quality of Service) on page 6-23- - -Web Browser Web Browser on page 6-10 - - -Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-19IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs•Video QoS (Quality of Service) - Actively joins a multicast stream and measures the subjective video quality. This test operates identically to the Video QoS test on other interfaces, such as the 10/100/1G interface. For more information, see Video QoS (Quality of Service) on page 6-23.•Change Channel - Actively joins a multicast stream and measures the time required to switch to another stream (that is, to “change the channel”). This test operates identically to the Channel Change test on other interfaces, such as the 10/100/1G interface. For more information, see Change Channel on page 6-51.•Channel Guide Settings - Allows you to configure the use of a channel guide for IP video testing, identical to other comparable functions on the unit. For more information, see Channel Guide Settings on page 6-53.7.4 Join MoCA Network In-Line (Bridging and passive testing)(Select MoCA-RF > MoCA > Join MoCA Network In-line)The MoCA module features dual MoCA interfaces which allow the unit to bridge traffic on a MoCA network and perform passive monitoring, typically for video quality measurement. For example, the unit could be placed in-line with an STB to monitor video traffic flowing across the bridge to the STB:Figure 7-12 Bridged MoCA connection setup - ExampleOnce a bridge is established, the unit can also perform the full suite of active testing in either direction.MoCA STB (connected)Coax jack, connecting to other STBs, router, etc.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-20Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs7.4.1 Join MoCA Network In-Line setup parametersThe setup parameters are functionally identical to those in the Join MoCA Network setup screen. For more information, see Join MoCA network setup parameters on page 7-5.Additionally, note the following:• Be sure that the unit is properly connected on the network before attempting the join. For more information, see Where to place the unit for bridging on page 7-21.• The specified parameters (Frequency, etc.) are used for each side, under the assumption that you are bridging two segments of the same network.• Upon successful synchronization, the main in-line testing menu appears:Figure 7-13 Main in-line testing menu• ECB functionality (if enabled) is only available for the “B” side network. For more information, see About MoCA and 10/100/1G interface bridging (ECB) on page 7-23• The in-line testing menu provides IP-related functionality for the A side of the connection, which operates identically to a single-ended connection established with the Join MoCA network command. See the respective areas of this document for more information, such as IP Network Setup on page 7-17.NOTE: The process of obtaining an IP address may temporarily disrupt video-on-demand (VOD) traffic. If you have a video stream running, you may need to restart it after address retrieval.• If passive testing is desired afterward, you may need to re-initiate the desired stream (such as a video stream), because the stream may not be present after the interruption caused by disconnecting the cable. For example, if you want to perform passive video testing, use the STB to select a channel to start the stream.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-21IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsNOTE: If you have set up the bridge properly, you should be able to view the video channel on a TV, even while testing the stream for quality. Therefore, a TV may be the best way of ensuring that the test stream has been started.7.4.2 Bridge setup and operational detailsThe following sections describe the bridging process and setup in more detail:•Where to place the unit for bridging on page 7-21•Bridging a cable with multiple networks on page 7-22Where to place the unit for bridgingThe primary reason for creating the bridge is to passively monitor traffic. Therefore, you must place the unit between the router and the device receiving the traffic, such as an STB. For example, the following setup would allow you to monitor video traffic received by STB 2:NOTE: Always connect the “A” side port in the direction of the router.Figure 7-14 Bridging example - CorrectNote that this setup provides visibility to STB 2 traffic only. To monitor STB 1 traffic, the unit would need to be placed between the router and that STB.When setting up the bridge, you should be sure that there is no external connectivity between the two MoCA ports. The unit attempts to join separate MoCA networks with the same channel on each side, which is not possible if the cable is interconnected. For example:SplitterTo routerRIGHT STB 1STB 2Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-22Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 7-15 Bridging example - IncorrectNOTE: In the case where a WAN and LAN both operate on the same cable, the unit can bridge a single channel only. See Bridging a cable with multiple networks on page 7-22 for important details on this and other operational details.Bridging a cable with multiple networksThe unit bridges a single MoCA channel only. Therefore, for architectures where a LAN and WAN both operate on the same cable, one network will be effectively blocked while the unit is synchronized with the other, at the point where the unit is connected. In most circumstances, this will have no adverse effect on the network or related testing, as most devices belong to a single network only. If the unit is configured as recommended in this documentation, no disruption of overall LAN/WAN functionality should occur.7.4.3 Passive video testingFrom the main in-line testing menu (Figure 7-13 on page 7-20) you can select Passive Tests > Unicast Video QoS or Passive Tests > Multicast Video QoS to launch a passive video quality measurement test. From the standpoint of input parameters and test results, these tests are identical to their active, single-ended counterparts except that the unit does not join a video stream. Rather, it uses the specified IP address and other identifying information to mirror an existing stream to the analysis software, leaving the original stream unaffected. For more information on general setup for passive video testing, see Bridge setup and operational details on page 7-21.7.4.4 In-line MoCA statisticsWhen you select MoCA Statistics A Side or MoCA Statistics B Side from the main in-line menu, the unit proceeds to statistics pages for the network on the respective side. All of the functions in these SplitterTo routerWRONGPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-23IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecspages are identical to their single-ended testing counterparts, except that you previously chose which side (A or B) to test. For more information, see MoCA Network Statistics on page 7-9.7.4.5 About MoCA and 10/100/1G interface bridging (ECB)Because the MoCA and 10/100/1G interfaces are logically connected by a common Ethernet switch, the unit can act as a bridge between MoCA and Cat-5 Ethernet, commonly called an ECB (Ethernet/coax bridge). For example, the unit can allow a computer to join the MoCA-based LAN or WAN through its 10/100/1G interface:Figure 7-16 Bridging a computer to the networkECB functionality must be specifically enabled when you join a MoCA network. Currently, the unit does not provide any test functions directly related to this bridge setup, but the use of a laptop on the network may be useful for isolating problems with Ethernet bridging devices and perhaps advanced functions using the computer itself.7.5 MoCA Quick Test(Select MoCA-RF > MoCA > MoCA Quick Test)-or-(MoCA-RF > MoCA > Join MoCA Network > MoCA Quick Test)Coax10/100/1G interfaceEthernetIP trafficPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-24Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsThe MoCA Quick Test is a set of existing MoCA activities, organized into a single, scripted test for a quick and comprehensive analysis of a MoCA network.7.5.1 Testing flow and results (MoCA Quick Test)The test can be run before or after the unit has joined a MoCA network. If run before, the first step is to join the network using the parameters specified in the setup screen; otherwise, that step is skipped. Once the unit is fully synchronized, the remainder of the MoCA Quick Test involves the retrieval and evaluation of a variety of network statistics. These statistics represent the same data that can be retrieved manually (see MoCA Network Statistics on page 7-9), except that the MoCA Quick Test automatically evaluates all applicable thresholds to present a simple pass/fail summary of network conditions.NOTE: The unit can apply delays during the initiation of the test that may be essential for producing meaningful results. For more information, see About intentional test delays (MoCA Quick Test) on page 7-26.While the test runs, it produces a running status of events in a Log tab. The following list describes the general stages of the test and the meaning of the results.1. Determination of network type and existing nodes - The test reports the MoCA version in use and a summary of all nodes active on the network, including the unit. All subsequent stages also include the unit as applicable.2. Bandwidth evaluation - The test analyzes the bit rates of all paths between all nodes, looking for any threshold violations. The data analyzed is the same as described under Bandwidth page (MoCA Network Statistics) on page 7-10.3. MoCA network statistics evaluation - The test analyzes general MoCA statistics, such as packet loss and error counts. A single lost or errored packet will fail this stage. The data analyzed is the same as described under MoCA Statistics page (MoCA Network Statistics) on page 7-11.4. Ethernet statistics evaluation - The test analyzes general Ethernet statistics, such as packet loss and error counts. A single lost or errored packet will fail this stage. The data analyzed is the same as described under MoCA Statistics page (MoCA Network Statistics) on page 7-11.5. Node stats evaluation - The test analyzes statistics separately for each network node (that is, the path between the unit and each node), the same data described under Node Stats page (MoCA Network Statistics) on page 7-13.6. Bit loading evaluation - Related to the general node stats, the test analyzes the bit loading for the receive and transmit links for each node, the same bit loading data as described under Node Stats page (MoCA Network Statistics) on page 7-13.7. Summary - When the test finishes, it presents a general summary, including an overall evaluation of the network labeled MoCA network. If any stage has produced a failed result, the entire test receives Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-25IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsan evaluation of FAIL. If any stage has produced a marginal result but no stages failed, the network receives an evaluation of MARGINAL.In the Log tab, stages are marked using colored icons according to thresholds that were evaluated during the process. A single failed evaluation causes the respective stage to be marked as such. In the absence of any failures, a single marginal evaluation causes the respective stage to be marked as such. Note that a failure does not mean that the testing process could not complete, only that a threshold was violated. For more information on thresholds and coloring, see View/Edit Thresholds on page 7-28.NOTE: If a stage is marked as marginal or failing, you can press the respective area on the touchscreen in the Log tab to jump to those respective results.Figure 7-17 MoCA Quick Test results - Log tabIn addition to a log of these stages, the test also produces a set of tabs that show much of the actual data that was measured and analyzed. These tabs have some similarity to the pages produced when manually retrieving network statistics, except that the MoCA Quick Test displays non-updating snapshots of the data retrieved during the test only. For any node that produced a metric violation, a separate tab is also produced showing the applicable details on that specific node:Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-26Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 7-18 MoCA Quick Test results - MoCA tab7.5.2 About intentional test delays (MoCA Quick Test)Optionally, you can introduce delays into the MoCA Quick Test process to reduce the possibility that non-applicable errors will cause the test to fail. These delays are configured in the MoCA thresholds area (see Thresholds on page 7-28). The following paragraphs explain the purpose of these delays in more detail.When a device (such as the unit) joins a MoCA network, some instability is expected as that device negotiates and forms the link. This instability may include reduced bandwidth and/or dropped packets such as MoCA admission packets. Therefore, to account for initial network instability and to prevent spurious failures of the MoCA Quick Test due to normal network behavior, the test provides two configurable delays:•“Initialize” delay - A delay between the initial network synchronization and the time when the unit begins to monitor network traffic. After the expiration of this period, all previous data is discarded and packet count registers and other results are reset as applicable.NOTE: In the Thresholds area, you can select a value of Auto for this setting. With this setting, the unit automatically selects a delay based on the total number of nodes detected on the network at the time of synchronization, with a higher number producing a longer delay. For example, 8 nodes will cause approximately 1 minute of delay, while 16 nodes will cause approximately 3 minutes. For optimal performance (especially on networks with fewer nodes), Auto is recommended.•“Settle” delay - A delay between the expiration of the “initialize delay” and the time that the primary portions of the analysis begin.Preliminary issue - Limited distribution only!
Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-27IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsIn summary, the two delays work together to allow the network to stabilize, then to allow enough traffic to arrive in order to produce meaningful results. Note that when the MoCA Quick Test is launched while the unit is currently synchronized to a network, the “initialize” delay is never used; however, packet count and result registers are always reset before proceeding with any MoCA Quick Test analysis. If a “settle” delay is configured, it is always implemented regardless of whether the unit was synchronized initially.The unit is preconfigured with defaults for these settings. If you do not know the precise settings that are applicable to your testing architecture, Spirent recommends that you maintain the defaults.7.6 System menu settings/controls (for MoCA)Under System > System/Module Settings > MoCA-RF Module > MoCA, the following areas are available that control important module settings:•Vendor MAC Address on page 7-27•Thresholds on page 7-287.6.1 Vendor MAC Address(Select System > System/Module Settings > MoCA-RF Module > MoCA > Vendor MAC Address)The Vendor MAC lookup table associates MAC addresses with equipment manufacturers/vendors, used to correlate an address with its respective vendor in the Node Stats screens (see Node Stats page (MoCA Network Statistics) on page 7-13.) That is, the unit is able to determine MAC addresses from the network, but it may need to use this table to correlate an address with a vendor name. During testing, if the unit is unable to correlate an address with a vendor in this table, it reports the vendor as Unknown.Typically, the IEEE issues MAC addresses to a specific vendor in blocks which can be identified by the first 6 octets (first 6 hexadecimal digits). As such, the lookup table should contain any 6-digit prefixes that the unit might encounter, along with the vendors to which they apply. From the factory, the table is prepopulated with a set of known values for current MoCA equipment vendors. If necessary, the screen allows you to edit and augment the table. Note that the Description is for informational purposes only within the lookup table.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-28Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 7-19 Vendor MAC Address lookup tableNOTE: The unit has an additional, internal table that it uses to look up any address not contained in the Vendor MAC Address table. This internal table contains information similar to any publicly-available address lookup on the internet. If the unit correlates an address using the internal table, it may add the corresponding entry to the Vendor MAC Address table. In this manner, you have the opportunity to edit the vendor information that appears subsequently for that address range.7.6.2 Thresholds(Select System > System/Module Settings > MoCA-RF Module > MoCA > Thresholds)This screen provides access to:•View/Edit Thresholds on page 7-28 - Allows you to view and possibly edit individual thresholds on the unit•Download Thresholds on page 7-30 - Allows you to set all thresholds as a batch by importing a threshold settings fileView/Edit Thresholds(Select System > System/Module Settings > MoCA-RF Module > MoCA > Thresholds > View/Edit Thresholds)The threshold table allows you to view and edit values that affect:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-29IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs• The coloring of results in the network statistics pages (see MoCA Network Statistics on page 7-9)• Pass/marginal/fail determinations during the MoCA Quick Test (see MoCA Quick Test on page 7-23)• Certain other behaviors of the MoCA Quick TestThresholds are specified as ranges, such as “Pass” ranges and “Fail” ranges. For coloring and evaluations related to thresholds, the unit uses:•Red/Fail for a metric that falls within the “Fail” range-or-If the respective threshold does not include a “Fail” range, a metric that falls outside the “Pass” range•Yellow/Marginal for a metric that falls within a “Marginal” range, if the respective threshold includes such a range•Green/Pass (or no coloring) for a metric that falls within the “Pass” rangeAdditionally, note the following:• When specifying thresholds, the unit enforces theoretical/technical limitations. For example, a bit rate cannot be less than zero. In general, if the inherent lower or upper range of a threshold represents a technical limit, the unit restricts the editing of the field altogether.• For thresholds with pass, marginal, and fail ranges, the unit enforces continuity between the ranges, normally by disallowing the editing of certain fields. For example, the marginal Bit Rate range is automatically determined by the lower Pass and upper Fail values and is therefore restricted from editing.• In the Enabled column, you can disable any specific threshold which causes the threshold to have no effect on coloring or pass/fail evaluations. This feature may be useful for situations where testing with the unit is required but a final determination of appropriate pass/fail criteria has not yet been made.The following table describes the supported thresholds.Bit RateCP LenPhase OffsetLog Gain MeanPower AdjustDetermine the valid range for the respective parameters in the Node Stats pages and for the corresponding stages during a MoCA Quick Test (see Node Stats page (MoCA Network Statistics) on page 7-13). Additionally, the Bit Rate ranges determine the valid ranges for the bit rates between any two devices during the retrieval of the bandwidth table (see Bandwidth page (MoCA Network Statistics) on page 7-10).Bit Loading (%)Bit Loading (bits)Together, determine when a bit loading profile is sufficiently robust, used for pass/fail evaluations during the MoCA Quick Test. If at least the specified percentage of subcarriers are carrying at least specified number of bits, the bit loading is considered passing. Otherwise, it is considered a failure.For general information on bit loading, see Node Stats page (MoCA Network Statistics) on page 7-13.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-30Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsAs an example, with the following setup, a Bit Rate value in the Node Stats screen would be colored yellow if it were between 180 and 189 Mbps and red if it were any higher:Figure 7-20 Thresholds screenDownload ThresholdsAs an alternative to editing thresholds directly on the unit, you can download a thresholds file to set all thresholds as a batch. This action completely overwrites all existing thresholds on the unit.For more information on the parameters required for the FTP transaction, see FTP connection parameters on page 2-59. The remainder of this section describes the required threshold file format.A threshold file uses a simple CSV format with lines in the following format:thld_name,from_value,to_value,enabledFor example:Q. Test Init DelayQ. Test Settle DelayIntentional delays to insert into the MoCA Quick Test process, in order to allow the network time to stabilize. These settings do not represent a range and therefore the To column is not applicable. Also, for Q. Test Init Delay, the option of Auto is provided. For more information, see About intentional test delays (MoCA Quick Test) on page 7-26.Include Admission ErrorsFor the MoCA Quick Test, allows you to prevent threshold evaluations from considering MoCA admission frame errors (by setting it to No). Admission frame errors may be normal on a network and you may want to use this setting to prevent them from causing failure indications during the test.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-31IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsPass Bit Rate(Mbps),190,300,YesIt must have the following filename:MoCAThresholds.datNote the following:• You should never change a threshold name (first field), otherwise the threshold will become unrecognizable and the unit will use a default instead.• If any value exceeds a theoretical limitation, the unit will reset it to a valid value. For example, if a percentage value exceeds 100, it will be reset to 100 upon import.• You can precede any line with an exclamation point (!) to restrict the setting from editing onboard the unit, for example:!Pass CP Len(slots),30,35,YesIn this case, the 30-35 range will be viewable on the unit, but will not be editable. Note that this condition cannot be undone except by importing another thresholds file to the unit.7.7 MoCA overviewThe following sections provide an overview of MoCA, with a focus on details applicable to testing with the MoCA module.7.7.1 About MoCAMoCA (Multimedia over Coax Alliance) is an “open, standard body promoting networking of multiple streams of high definition video and entertainment using existing coaxial cable already in the home.”1 MoCA has been formed because of the following two conditions that have recently converged:• The increasing need for packetized, IP-based protocols to deliver multimedia services, such as IPTV and video on demand (VOD), and• The historical lack of an appropriate physical medium to reliably transport high-bandwidth packetized data within the homeFor high-bandwidth packet transport, the ideal physical transport medium would be a network of fiber and/or Cat-5 copper cabling. However, most homes do not have this infrastructure and the installation of it can be costly and inconvenient. But most homes do have an existing coaxial cable network due to the prevalence of cable TV and outdoor antennas, so MoCA is intended to allow service providers to deliver next-generation, packet-based services over the existing coaxial cable found in the home. While other media typically exist such as phone lines, electrical wires, and wireless broadcast, coaxial cable is often favored for the following reasons:Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-32Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs• It is shielded.• Typically, an existing coaxial network already interconnects the video devices within the home, which are a primary target for broadband services.• Compared to wireless networks, wire-based networks are generally faster, more secure, and more reliable.The MoCA 1.1 and 2.0 standards allow up to 16 nodes per network. MoCA 1.1 allows a theoretical maximum data rate of 270 Mbps between devices and MoCA 2.0 allows a theoretical maximum of 800 Mbps, although actual data rates are normally lower due to line attenuation. For more information on how the network controls data rates, see MoCA physical layer on page 7-36.Note that the term “MoCA” may be used to describe the organization that promotes the transport technologies or the technologies themselves. For the remainder of this document, unless otherwise specified, “MoCA” is used to describe the transport standard, not the organization. For more information on MoCA as an organization, visit www.mocalliance.org.7.7.2 Example physical MoCA networkFor a brief explanation of MoCA, consider the following figure and the description that follows. This figure shows a fiber-to-the-premises (FTTP) architecture where an optical network terminal (ONT) terminates the fiber and converts network traffic to MoCA, where it is fed into the home.Figure 7-21 Example MoCA network, fed by an FTTP architectureONT (Fiber to MoCA)Provider network/ISP Fiber Coax/MoCA Coax/MoCACoax splitterMoCA STBMoCA STBMoCA routerMoCA to EthernetCat 5 /EthernetPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-33IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsMoCA operates using a hierarchical or “branching tree” physical topology with a “root” at the first coaxial splitter, with additional devices (or nodes) connected to one or more secondary splitters as “branches” distributed throughout the premises. The resulting logical network then appears as a mesh of point-to-point connections established between each of the nodes. This differs from a switched Ethernet network using twisted pair/Cat-5 copper, which typically uses a hub, switch, or similar device at a junction to manage traffic flow. In a MoCA network, all nodes are logically interconnected on a single mesh, including the router.On a MoCA network, a single node acts as the network coordinator (NC), with all other devices acting as member nodes. Using time-division multiplexing, the NC manages traffic flow by coordinating data transmission from all network nodes, including itself. In order to transmit, a node must request a time slot(s) from the NC which then periodically sends out a “schedule” of what node can transmit and when. Any MoCA-compliant device can act as the NC and typically a network is configured to automatically select the NC for optimal performance. Automatic NC selection also ensures that the network continues to operate if the current NC fails or is removed from the network.A single coaxial network can carry more than one MoCA network using different frequencies (or channels) to differentiate the two. A common use of multiple channels is to allow a WAN and a LAN to exist on the same physical cable. In the Figure 7-21 example, all nodes are interconnected by a single coaxial tree, with a single cable connected to the router. Therefore, both the provider WAN (wide area network) and the residential LAN (local area network) must operate on the same cables using different channels. Each node must be configured to request admission to the proper network, with the router configured to join both. Note that because the LAN and WAN are separate MoCA networks, they both have their own NCs, which may be the same node (the router) or may be different nodes.Despite the physical interconnectivity of this example network, the logical network concept operates identically to other networks with respect to member nodes. In the Figure 7-21 example, the WAN consists of the ONT and router only and the LAN consists of the router and all other devices except the ONT. Even though every node has both the LAN and WAN signals at its coaxial port, only the router is part of both networks. For example, the ONT will have the LAN signal available at its coaxial port, but it will be configured to join the WAN only at its respective MoCA channel.Figure 7-21 also shows an Ethernet-based connection to a computer, linked to the MoCA network by a MoCA/Ethernet bridge. While set-top boxes (STBs) and other multimedia devices are typically MoCA-ready and plug directly into the coaxial cable, home computers use twisted pair-based Ethernet or other protocols for networking. Because an IPTV provider may supply broadband internet access as well, a computer must interface with the MoCA network via the bridge (or perhaps a wireless connection) in order to reach the provider WAN.NOTE: As with any networking technology, there are a wide variety of configurations and devices available which may differ from this diagram. Consult Other MoCA network examples/scenarios on page 7-34 or a network engineer for more information about MoCA and the types of networks you may encounter.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-34Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs7.7.3 Other MoCA network examples/scenariosAside from the FTTP-based architecture shown in Figure 7-21 on page 7-33, MoCA implementations may take other forms, especially with regard to the type of network used by the provider to deliver broadband services to the premises. For example, the following figure shows a typical DSL-based MoCA architecture:Figure 7-22 Example MoCA network, fed by a DSL architectureIn this case, the residential gateway (RG) is connected directly to the telephone company twisted pair, where the DSL signal and provider WAN are terminated. The RG has a coaxial port for the residential LAN side of the network and therefore serves as an interface between DSL and MoCA. With regard to testing with the unit, the important item to note is that the cable only carries a single MoCA network (the LAN). While the unit can join a MoCA network on any channel, testing on the WAN in this type of network is not applicable, as it may be in the architecture shown in Figure 7-21 on page 7-33.For broadband service architectures delivered by a cable TV provider, the diagram might be similar to Figure 7-22 on page 7-35, except replaced by a DOCSIS network upstream from the RG. Again, this type of architecture would use MoCA to transport the LAN, but not the provider WAN.Note that other alternatives are possible, beyond those presented in this document. Consult a network engineer or administrator for more information on the type of network(s) you are likely to test with the unit.Telco NID Provider network/ISPTwisted pairCoax/MoCADSL modem / RG MoCA STBMoCA STBMoCA to EthernetCat 5 /EthernetDSLPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-35IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs7.7.4 MoCA functional overviewA MoCA network is designed for self-maintenance and dynamic adjustment for optimal performance. The following sections briefly describe the physical and media access layers (PHY and MAC, respectively), along with some details on the communications involved with network maintenance, especially as related to testing with the MoCA module. For more information, including descriptions of traffic not mentioned here, see the technical specifications related to MoCA.MoCA physical layerAt the physical layer, a MoCA network operates on one of several available RF channels between 500 and 1650 MHz, with each channel spanning 50 MHz (MoCA 1.1) or 100 MHz (MoCA 2.0) in its spectrum usage. The available channels are organized into bands, with only one channel per band permitted for use on any physical network. In some cases, though, two channels from different bands may be active on the same cable to allow the transport of two different logical networks, such as the case where a WAN and LAN are operating on the same cable. In this case, there are effectively two different MoCA networks on the same cable. For more information, see Example physical MoCA network on page 7-32.MoCA uses the adaptive constellation multi-tone (ACMT) technique to transform layer 2 (MAC) data and control frames, as well as physical layer probe frames, into QAM symbols. These symbols are modulated onto a channel's subcarrier frequencies to create a serial bitstream. The MoCA specifications allow a subcarrier to be modulated using any mode of QAM, up to 256-QAM which carries 8 bits per symbol (MoCA 1.1) or up to 1024 QAM which carries 10 bits per symbol (MoCA 2.0). The actual maximum bits per symbol that any given subcarrier can carry, however, depends upon the physical conditions which affect the ability of the line to reliably transport the subcarrier frequencies.For any coaxial network, the physical path between any two devices can vary widely due to line length, reflections, splitter configuration, and other conditions. Aside from overall attenuation, these characteristics also have a different effect on different frequencies, even subcarrier frequencies that are close on the spectrum. To account for these variances, member nodes regularly send physical-layer “probe” messages to each other to evaluate the physical network between them. Using this messaging, the nodes are able to construct an appropriate “modulation profile” for transmission to each other, which includes how many bits that each subcarrier should attempt to carry (known as the bit-loading). A profile may determine that some subcarriers can not reliably carry the maximum number of bits and mandate a lower number, or even restrict the transmission on certain subcarrier frequencies altogether. In any given network, each node has a separate profile for communication with each other node, which maximizes network performance.With its statistics-gathering features, the MoCA module can produce bit-loading graphs that plot how effectively subcarriers are carrying data to and from the unit. For more information, see Node Stats page (MoCA Network Statistics) on page 7-13.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-36Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsMoCA data link layerMoCA defines a MAC (media access control) protocol that determines how nodes may access the shared media to transmit/receive Ethernet frames. It specifies two general types of MAC layer frames:•Control frames - Frames that contain MoCA network management messaging•Data frames - Frames that contain the end-user application data (internet, IPTV, etc.)The two primary types of control frames are bandwidth requests and media access plans (MAPs). Because the meshed nature of the logical network allows only one node to transmit at any given time, the network coordinator (NC) must coordinate all transmission by all nodes. When a node wants to transmit, it sends a bandwidth request to the NC. In turn, the NC regularly broadcasts MAPs which are effectively precise schedules about which node can transmit and when. Not only does a MAP tell a node when it should transmit, it also allows the target node to know when to expect the transmission.Another type of media access control is the admission request and associated negotiations. When a new device is connected to the network, it must request admission to the network from the NC and then complete a set of qualifying steps. It finds the appropriate channel and the NC location by a mechanism known as beacons, which the NC also regularly broadcasts. Because admission control is only initiated by a new device, no admission control frames would be expected on a stable network. 7.7.5 Common coaxial cable problems that affect MoCAThe following cable-related issues can affect MoCA performance:• A fault in the cable, such as a short circuit or other condition which may affect the electrical continuity. Because a MoCA network is physically interconnected, a critical short-circuit can prevent the transport of all MoCA signaling to all devices, including the WAN and the LAN (see Example physical MoCA network on page 7-32).• A bad connection, perhaps caused by corrosion, a loose connector, or poor connector crimping.• Attenuation due to the excessive use of cable splitters or the general splitter configuration. In particular, the presence of “splitter jumps,” where two nodes communicate through the outputs of one or more splitters, can have an impact on channel characteristics. For example:Figure 7-23 Splitter jump, through a single splitterSplitter jumpIn OutPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 7-37IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs• Excessive cable length• A powered signal amplifier on the network that restricts the passage of frequencies in the MoCA spectrumUltimately, any condition that increases line attenuation will decrease the reach and performance of MoCA.7.7.6 About multiple MoCA versions on a single networkMoCA 2.0 provides backwards compatibility with MoCA 1.1, such that a MoCA 2.0-compliant node can operate at MoCA 1.1. Furthermore, if a network has both 2.0-compliant and 1.1-compliant nodes, the 2.0-compliant nodes can use 2.0 to communicate with each other, while using 1.1 for the other nodes. The following notes are applicable to this supported scenario:• Because of the time-division nature of MoCA transmissions, only a single node transmits at any given time. Therefore, at any given instant, only a single MoCA protocol is actively in use, which facilitates the use of multiple versions on a single network.• If a 2.0 node is transmitting to a another 2.0 node, it uses the 2.0 channel bandwidth of 100 MHz, along with any other 2.0 characteristics. Otherwise, the 1.1 bandwidth of 50 MHz is used.• The NC must be a 2.0 node to allow any 2.0 communications. Otherwise, all nodes must use 1.1 at all times.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 7-38Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-18: MoCA/RF - RF TestingThis section describes the RF-specific functions of the combined MoCA/RF module. This module adds:• Signal strength measurements, for both analog and digital (QAM) video channels.• For digital signals, common measurements such as MER and BER, along with a constellation diagram analysis tool.For specific function details, see:•Channel Sweep Test on page 8-2•Single Channel Test on page 8-4•Select Channel Guide on page 8-7•View Channel Listings on page 8-7Figure 8-1 RF main testing menu8.1 Important notes on handling the moduleSee Handling the MoCA/RF module on page 2-30.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-2Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs8.2 Channel Sweep TestThe Channel Sweep Test (available from the main RF menu) provides RF measurements for up to 12 channels on the wire, serving as a batch test of a group of channels. The results produced for each channel are a subset of the information produced when a Single Channel Test is run. For a description of these results, see Channel testing measurements/results on page 8-12.8.2.1 Channel Sweep Test setupIn the test setup, each tab represents a single channel to include with the test. Tabs without data populated are ignored. Note the following:• All channels share a common Location which determines the set of thresholds to use for flagging test results. This field must be set in the first tab. For more information, see Thresholds on page 8-23.• In each tab, you can specify a channel either by channel number or by frequency/type. To select channels by number, you must have an active channel guide on the unit which allows the unit to correlate the number with a frequency and type. Otherwise, channel frequencies and types can be specified directly. In general, the use of a guide is preferred. For more information on channel guides, see View Channel Listings on page 8-7.Additionally, note the following about channel selection:– The unit will reject any frequencies that are not valid according to the current EIA channel table on the unit. – If the unit can correlate a frequency with a channel in the active channel guide (if applicable), it will automatically select the Type and disable the input field.Figure 8-2 Channel Sweep Test setupPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-3IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs8.2.2 Channel Sweep Test resultsFor the results, note the following:• See Channel testing measurements/results on page 8-12 for detailed results descriptions.• In the graphical view, the table at the bottom shows details for the selected channel only, identified by a lighter color on the bar graphs. Use the left/right arrow keys to change the selection.NOTE: The PASS/FAIL indication also applies to the selected channel only. See Channel testing measurements/results on page 8-12 for more information on pass vs. fail.• In the graphs and tables, any result that has violated a configured threshold is colored red. See Thresholds on page 8-23 for more information.• Results are presented only for channels to which the unit could successfully synchronize.• All results for all channels are measured and calculated one time only. The test does not perform repeated measurements like the Single Channel Test.• Results for out-of-band (OOB) channels include power measurements only. For more information, see About out-of-band (OOB) channel support on page 8-18.•Use the F1 key (Table / Graph) to toggle between the graphical and general tabular views. The tabular view shows signal power measurements only, for all tested channels.• While in the graphical view, use the F2 key (Audio / Video) to toggle between audio and video signal measurements.•Use the Channel shortcut (F3) to launch the Single Channel Test (see Single Channel Test on page 8-4).Figure 8-3 Channel Sweep Test results, with the second channel selectedPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-4Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs8.3 Single Channel TestThe Single Channel Test (available from the main RF menu) provides measurements on a single specified channel.8.3.1 Single Channel Test setupThe test initiates immediately with no setup parameters. All test parameters are configured in the results screen.8.3.2 Single Channel Test resultsBy default, the test runs continuously and operates based on parameters that can be configured in the results screen. See below for further information on selecting the channel for analysis and other setup parameters. For more information on the RF-related measurements in this screen, see Channel testing measurements/results on page 8-12. Figure 8-4 Single Channel Test results, with a violation related to signal powerNote the following:• While actively running, the test resamples its measurements periodically with the following effects on reported results:– For digital channels, the data used to calculate BER (Pre-FEC and Post-FEC) and MER is added to all previous data and the results are recalculated, adding to their precision. See Digital channel test results on page 8-15 for more information.– All other results reflect the instantaneous values from the most recent measurement interval.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-5IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs• If the test cannot synchronize with the channel because the power is too low, it will still produce a power level reading; however, you should be aware that the channel may not exist and the power measurement may represent noise only.• Results for analog channels include power measurements only. Additionally, note that:– The unit measures the “video” frequency only, not the audio.– The unit does not tune or lock onto the channel by any method. It simply measures power at the video frequency.• Results for out-of-band (OOB) channels include power measurements only. For more information, see About out-of-band (OOB) channel support on page 8-18.• In the graph and table, any result that has violated a configured threshold is colored red. Furthermore, if a single results parameter violates a threshold, the test status is reported as FAIL. See Channel testing measurements/results on page 8-12 for more information.The screen provides a set of important setup controls that can be operated while a test is ongoing, either by:•Using the Display menu (F1), or• Using the arrow keys on the unit keypad. When using the arrow keys, use the:– Left and right arrows to shuffle between controls– Up and down arrows to change the current settingFigure 8-5 Display menuOn the display, only a single control can have the focus at any given time. Therefore, for reliable behavior when you use the arrow keys, you should remain aware of which control has the current focus. The following table describes these controls.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-6Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 8-1 Test display controlsAdditionally:•The Tests menu (F2) provides quick access to any other top-level test supported by the module.•The Settings menu (F3) provides quick access to the module settings areas normally found under the System menu.Display control FunctionRunning (Display > Running) Pauses and restarts a continuously-running test.Channel/Frequency (Display > Channel/Frequency) Sets the channel for analysis. You should specify:A Channel number or designation, which refers to a channel in the active channel guide (see View Channel Listings on page 8-7).-or-The frequency and type of a valid EIA channel. These fields available to test channels that are not in the active channel guide and/or to run tests without a guide imported to the unit. Generally, the use of a guide is preferred, when feasible. If the unit locates the frequency in the active guide, it will automatically populate the Channel field. Additionally, note the following:• The unit will reject any frequencies that are not valid according to the current EIA channel table on the unit.• If the unit can correlate a frequency with a channel in the active channel guide (as applicable), it will automatically select the Type and disable the input field.Location (Not available in the Display menu) Specifies the threshold set to apply. The thresholds control pass/fail and coloring aspects, but otherwise do not affect how measurements are calculated. For more information, see Thresholds on page 8-23.Reference LevelDivision(Display > Reference Level and Display > Division) Control the layout of bar graphs (see Bar graph and power measurement notes on page 8-13).Bar Graph/Constellation(Display > Bar Graph and Display > Constellation) Toggles between the bar graph display and the constellation diagram., for digital channels only For more information on the constellation diagram, see About QAM and the constellation graph on page 8-18).Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-7IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs8.4 Select Channel GuideThis function allows you to select the active channel guide, if multiple guides are present on the unit. The unit uses the channel guide to verify valid frequencies and to correlate frequencies with channel numbers, in various areas of testing.Note that:• Only one guide may be active at any given time.• You can view the channel listings in the active guide at any time with the View Channel Listings function (see View Channel Listings on page 8-7).• You can download new and/or updated guides to the unit as required (see Download RF Channel Guide(s) on page 8-23).8.5 View Channel ListingsFrom the main RF menu, View Channel Listings allows you to view two channel tables on the unit:• The standard listing of TV channels and their associated frequencies (see EIA CATV tab on page 8-7)• The channel guide currently active on the unit, which should reflect the architecture under test (see Lineup tab on page 8-8)8.5.1 EIA CATV tabThis tab displays a list of channel numbers/designations and their associated frequencies supported by the module tuner, according to EIA standards[4]. Channels in the active channel guide (see Lineup tab on page 8-8) should each reference a channel from this list, which is how the unit determines the frequency(ies) for testing. The information in this tab is fixed according to the firmware package on the unit and cannot be changed by end users. For a listing of these channels, see Supported channels and frequencies on page 8-27.Column DescriptionCH Channel number or designation. Note the following:• This is not the number displayed in test setup and results screens. Rather, it is the number that should be referenced by a channel in the active channel guide (Lineup tab on page 8-8), as applicable.• Out-of-band (OOB) channels, if present, typically appear with an OOB designation rather than a number.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-8Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 8-6 EIA CATV tab8.5.2 Lineup tabThis tab displays the customer-specific channel lineup configured for the unit, as found in the active channel guide. During testing, when a channel is selected by number, the unit looks up that number in this lineup, then uses the remaining information in the channel entry to complete the testing request. Note that:• If the unit has multiple guides imported, you can select the active guide with the Select Channel Guide function (see Select Channel Guide on page 8-7).• You can download new and/or updated guides to the unit as required (see Download RF Channel Guide(s) on page 8-23).• If no channel guide is present or the active channel guide is not correctly formatted, this function will fail. For more information on the required file format, see Channel guide file format and general handling notes on page 8-23.Video Video carrier frequency, for analog channels.Audio Audio carrier frequency, for analog channels.Digital Center carrier frequency for digital channels.Column DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-9IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsFigure 8-7 Lineup tabColumn DescriptionChan Channel number or designation for the lineup. This number/designation is used in test setup and results screens, as applicable. For example, when you specify a channel for a Single Channel Test, you should specify this value.Name Channel name or abbreviation, for informational purposes within the unit testing and results screens.EIA Chan Channel number/designation from the standard list (see EIA CATV tab on page 8-7) that this lineup number references. During testing, the unit looks up frequency and channel type information for the channel using this number. It must be specified exactly as it appears in the configured EIA list.EIA Video FreqChannel frequency (or video frequency, for analog channels), drawn from the standard list based on the EIA Chan number (see EIA CATV tab on page 8-7).Type Channel type, which the unit uses to determine how testing should be conducted on the channel. Valid values include:•64QAM (digital)•256QAM (digital)•Analog•QPSK (required for out-of-band (OOB) channelsPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-10Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs8.6 Close-Out Test ScriptThe Close-Out Test Script is a tool for running a series of Channel Sweep tests at various locations within a subscriber premises, recording the results in a single file that can be transferred from the unit following the testing. The intent is to produce a composite collection of results representing the service at a single subscriber location.The specific channels to test during the sweep are specified in the System menu. For more information, see RF Script settings on page 8-26.8.6.1 General procedure for running the Close-Out ScriptThe transfer of a results file requires configuration of the Admin Port on the base unit. Because it is normally not feasible to maintain this configuration while moving between rooms to test the RF network, the following general sequence of events should be followed:• Launch the script and perform measurements in all desired locations (see Launching the Close-Out Script on page 8-10).• Exit the script. If presented with results handling options, select the option to keep or preserve results.• Connect the Admin Port to a network that is able reach the computer to which the results should be transferred. (System > Admin Port, see Admin Port on page 5-5 for more information).• Launch the script again, selecting the option to FTP results, rather than to run the script again. When untransferred results are remaining on the unit from a previous script run, the unit will produce a prompt with the FTP option the next time the script is launched.For more information on results handling and FTP, see RF Script settings on page 8-26 and Close-Out Script results management and transfer on page 8-12.8.6.2 Launching the Close-Out ScriptNOTE: Before running the script, you should be sure that the primary script settings are configured correctly (see RF Script settings on page 8-26).When the script is launched, the unit may present a screen with options for handling results from a previous script run, if it detects results from a previous run that have not been transferred yet. Until successfully transferred from the unit or otherwise purged, the results from a previous script remain on the unit and cause this prompt to appear, providing the following options:Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-11IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs•Purge - Removes all results from the previous script run and proceeds to the script page.•Keep - Proceeds to the script page to run a new Close-Out Script and appends any new results to the previous results set.•Proceed to FTP - Skips the script testing functions and proceeds directly to the FTP page (see Close-Out Script results management and transfer on page 8-12).Note that similar options are presented when you exit the script.Once the script is fully launched, the setup screen allows you to select the following:Figure 8-8 Close-Out Script setupWhen you click Start, the test runs according to the configured settings and displays a results screen similar to the Channel Sweep test (see Channel Sweep Test results on page 8-3). At this point, you can:Setting DescriptionClose-Out LocationThe room within the premises where the current iteration of testing should occur. It is assumed that the unit has been physically connected to a coaxial outlet within that location. Note that each location will display the total number of outlets tested for that location as testing progresses.Outlet The outlet number, within the selected location. This field may be useful if a room has multiple outlets which require testing. During the testing process, the unit only permits a single test run at any given outlet number for a specific room.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-12Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs•Select Next Test to return to the setup screen and run another iteration at a different location.•Select Done to exit the test and prepare for the transfer of the results (see Close-Out Script results management and transfer on page 8-12).8.6.3 Close-Out Script results management and transferThe script is designed to store results from the previous script run, ready for transfer via FTP to an external computer after testing is complete. Normally, the FTP process is performed independently following script testing. For more information on general testing flow, see General procedure for running the Close-Out Script on page 8-10Once initiated, the onscreen prompts lead you through the FTP steps, noting the following:•An Admin Port should be configured with valid, routable IP information before attempting the transfer. The FTP action requires the unit to be properly networked with the target server via this port.• If a target server is unavailable, the script allows you to exit with the option whether or not to discard saved results. If you choose to retain results, you will have the option to attempt the transfer again when the script is launched the next time.• Results files contain a complete set of measurement results for each channel measured during each interval. In a results file, each set of results is preceded by a header that indicates the location and outlet number for the respective test.• Once a results file is successfully transferred, the unit no longer produces any prompts related to those results, such as purge and transfer prompts. The next test begins a new set of results. Note that all results files remain on the unit indefinitely where they can be viewed, deleted, and/or transferred with the Record Manager. For more information on the Record Manager, see Record Manager on page 5-1.• During the FTP action, any file on the server with the same name as a file on the unit will be overwritten.• For more information on setting up an FTP server on a remote computer, see FTP server installation and setup on page 2-58.8.7 Measurement descriptions and theory8.7.1 Channel testing measurements/resultsThe following information describes the measurements that are produced by the Single Channel Test and the Channel Sweep Test. Note that these descriptions include common industry standards which may or may not be applicable to your environment.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-13IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsNOTE: Any individual result that appears in red (including a bar graph) has violated a threshold configured for the unit. For more information on configuring thresholds, see Thresholds on page 8-23.PASS/FAIL statusIf any measurement for a channel violates the respective configured threshold, the channel is reported as FAIL. For the Channel Sweep Test specifically, note that the PASS/FAIL indication refers to the selected channel only.For more information on configuring thresholds, see Thresholds on page 8-23.Bar graph and power measurement notesBar graphs are provided for a simple graphical representation of certain measurements, such as power levels. RF testing includes two basic types of bar graphs.The first type uses a chart format, with the currently-active thresholds shown as shaded areas. For example, the following graph shows a power measurement of -1.30 dBmV, slightly below the lower threshold of 0.0 dBmV and therefore shown as a violation:Figure 8-9 Bar graph notationsOther important notes about this type of bar graph include:Lower threshold(0 dBmV)Upper threshold(15 dBmV)Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-14Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs• These graphs include a configurable Reference Level, shown as Ref Lvl (dBmV) in the previous example. This value sets largest value for the y-axis and allows you to shift the range up and down to get a better view of the measurement data. In some results screens, the reference level includes the choice of Auto, with which the unit attempts to center the data automatically.• Some graphs also include a configurable Division setting, indicated by the 10 dB/div label in the previous example. This setting indicates the number of respective units in each shaded division on the graph. In the previous example, the graph contains 6 divisions of 10 dB each, allowing the graph to span 60 dB. A different Division setting would increase or reduce that span.The other type of bar graph provides a simple graphical representation of power levels. Above a bar, the measured power (in dBmV) for the respective signal is displayed. On each bar, a “bracket” provides a rough estimation of the threshold range configured for the respective power level (see Thresholds on page 8-23).Figure 8-10 Bar graph notationsNote that in all cases, the unit is designed to accurately measure power down to -30 dBmV. In some cases, if a signal below this level is detected and can be measured, the unit will display a value below -30. If this occurs, it should be noted that the measurement may not be accurate. Furthermore, for very low measurements, it is possible that the unit is measuring noise on the line, rather than a broadcast video signal.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-15IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsResults screen icons and threshold violationsIn some results screens where individual results are compared against thresholds, the unit presents icons that more precisely indicate the outcome of those comparisons. The following table describes these icons. For more information on thresholds, see Thresholds on page 8-23.Digital channel test resultsPass.Indicates a result that exceeded a maximum threshold.Indicates a result that was lower than a minimum threshold.Indicates a general failure condition, possibly but not necessarily related to a specific threshold comparison.Measurement DescriptionFrequency Center carrier frequency for the channel.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-16Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsMER(Modulation error ratio)A performance metric for a digitally-modulated signal, typically used to gauge the reliability of signal transmission. Sometimes (perhaps erroneously) referred to as a digital carrier-to-noise measurement, MER is the ratio of the carrier's average symbol power to the carrier's average error power. A higher number indicates a better quality of service (that is, less influence from noise, linear/non-linear distortions, and ingress). Actual minimums for reliable digital transport may vary according to architectures and other conditions, but suggested minimums for an equalized measurement are 23-27 dB for 64-QAM and 28-31 dB for 256-QAM.The calculation of MER is directly related to the placement of points on a constellation graph. An “ideal” symbol arrives in the center of its respective “cell” on the graph, so graphs that display plots close to their respective centers correspond with a higher MER. Symbols displayed further from the center and/or forming “fuzzy” patterns correspond with a lower MER.Because MER is calculated from sampled bits, the precision increases with the sample size. Therefore, tests that run repeated measurements can keep a cumulative data set and continue to increase the precision of the MER calculation.For more information about constellation graphs, see About QAM and the constellation graph on page 8-18.P/V Ratio or Peak/ValleyPeak-to-valley ratio, the difference between the highest and lowest power levels across the frequency band tested, in dB. It is effectively the highest versus the lowest power level detected across the bandwidth of a digital channel. On a power level spectrum graph, a perfect digital signal should appear “flat” across the frequency band in use by the channel. However, portions of the bandwidth are normally received at higher power levels than others due to distortions and impairments.Ideally, this number should be as low as possible, with 3 dB commonly recommended as a maximum. Significant differences in power levels across the band interfere with the ability of receiving equipment to decode the modulated signal.Measurement DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-17IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsPre-FECPost-FEC(Pre- and post-FEC BER - Bit error ratio)The ratio of errored bits to total bits, before and after the unit applies forward error correction (FEC) with Viterbi and Reed-Solomon algorithms. The two measurements are intended to show the signal as it exists on the wire and the signal after a typical receiver applies FEC, the latter of which more accurately represents the signal that will be decoded and processed.Because BER is calculated from sampled bits, the precision increases with the sample size. Therefore, tests that run repeated measurements can keep a cumulative data set and continue to increase the precision of the BER calculation.BER measurements may be presented in scientific notation. For example, a measurement of 1.2e-5 equals 1.2 x 10-5 or 0.000012, which is equivalent to 12 errored bits per 1,000,000 (1 million) transmitted.FEC operates using redundant information that is intentionally transmitted with a digital signal that provides two primary functions:• A means of determining when bit errors occur, similar to a checksum• A limited ability to reconstruct the original bitstream in the event of bit errorsIdeally, the post-FEC ratio should be very small, such as zero to one error per billion bits transmitted (1.0e-9). Small increases in bit errors can have a rapidly deteriorating effect on digital video quality, depending on where the errors occur.Important note about BER and configured thresholds: The “lower” a BER threshold, the longer it takes the unit to accumulate enough sample data to accurately display a BER calculation and indicate threshold violations. For example, if a BER threshold is set to 1.0e-9, the unit technically requires a sample set of at least a billion bits to properly detect a threshold violation and therefore may introduce significant delay with the presentation of the result.Measurement DescriptionPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-18Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs8.7.2 About out-of-band (OOB) channel supportThe unit supports power measurements on OOB channels using the Single Channel Test and the Channel Sweep Test. An OOB channel is a provider-specific channel typically used for the transfer of data between a set-top box (STB) and provider equipment, such as the interaction with an on-screen channel guide. An OOB channel normally uses a non-standard single frequency chosen specifically to serve the desired purpose without interfering with normal channel frequencies.To enable testing on OOB channels, you must:• Have the channel(s) configured in the main channel list (EIA, etc.). The main channel list is fixed on the unit according to the installed firmware package. For more information, see EIA CATV tab on page 8-7.• Have the channel(s) configured in the active channel guide, such that they may be specified for the Single Channel Test and/or Channel Sweep Test setup. Like any channel, they must be specified exactly as shown in the active channel guide. For more information, see Lineup tab on page 8-8 and Download RF Channel Guide(s) on page 8-23.Only power level measurements are performed on OOB channels. When an OOB channel is tested, no other results will appear. Furthermore, the unit supports separate pass/fail thresholds for OOB channels, up to a maximum of two separate channels. For more information, see About out-of-band (OOB) channel support on page 8-18.8.7.3 About QAM and the constellation graphQAM (Quadrature Amplitude Modulation) is one of many methods for transporting digital data over analog waveforms such as RF sine waves. With QAM, the fundamental technique of representing digital bits is through amplitude modulation of the analog waves, where a prescribed set of amplitudes are assigned to different binary digits.As an example of amplitude modulation, consider an amplitude scheme that is segmented into four different levels. This type of scheme can present one of four digits (that is, two bits) with each wave cycle, with the following hypothetical wave modulated with a binary “10”:Figure 8-11 Hypothetical RF waveform representing a binary 10 (decimal 3)00011011Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-19IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsWith this method of modulation, the strength and consistency of the carrier frequency are critical for reliable data transmission. For any given scheme, a weaker signal forces the data points closer together, which decreases the tolerance for error if the waveform peaks do not fall exactly at the expected level. Conversely, an increase in amplitude “space” with stronger signals allows the use of schemes with a greater number of data points, increasing the amount of binary data that can be modulated on each wave cycle.QAM uses this technique of modulation with one variation: the addition of a second waveform in order to double the amount of data that can be sent with each cycle. The two waves, known as the “I” and “Q” signals, travel at a fixed 90 degrees out-of-phase. With each cycle, both waves represent amplitude-modulated binary numbers which collectively represent a larger set of bits. Continuing with the previous example of four data points per cycle, the following QAM cycle might represent a binary “1011”:Figure 8-12 16-QAM cycle showing a 1011-modulated symbolThis particular scheme is known as “16-QAM,” as each modulated cycle (also known as a symbol) transports a total of four bits, allowing one of 16 different binary numbers to be modulated (0000 - 1111). Other QAM schemes such as 64-QAM and 256-QAM operate in a similar fashion, except that they contain more amplitude data points. For example, 64-QAM defines eight data points which allows each wave to individually carry a binary number between 000 - 111 (three bits) per cycle. Collectively, then, the I and Q signals transport six bits per symbol, a binary 000000 - 111111 (0 - 63 in decimal notation).A constellation diagram is a common means of graphically representing a QAM scheme. These diagrams use a grid to indicate each potential binary number possible per symbol, using the x- and y-axes to represent the amplitude data points of the I and Q signals, respectively. For example, the following constellation diagram represents 16-QAM:00011011I-signal(10)Q-signal(11)Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-20Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 8-13 16-QAM constellation diagramAside from a basic chart of binary numbers supported by a QAM scheme, a constellation graph is also a useful means of visually presenting the quality of an actual QAM signal, especially with respect to the consistency of amplitude measurements and their intended binary representations. Using a graph in this manner, the exact center of each “square” is designated as the point where the I and Q signals fall exactly upon a prescribed data point (that is, an expected amplitude), when the symbol is sampled and demodulated. For example, the following figure shows a “perfect” symbol that would be plotted as follows in the “1011” square:Figure 8-14 The plot of a “perfectly” modulated symbolConsider, however, a symbol that appears as follows at the point of demodulation:Figure 8-15 Imperfect amplitude levels0000 0100 1100 10000001 0101 1101 10010011 0111 1111 10110010 0110 1110 1010QI00011011I-signal(10)Q-signal(11)Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-21IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsIn this case, the variation of the actual amplitudes from the expected levels for perfect modulation would cause the symbol to be plotted off-center. Because the I and Q signals both deviate from the expected amplitude, the plot is pushed away from center on both axes:Figure 8-16 Imperfect symbol plotWhen the unit draws the constellation graph, it samples a small subset of symbols on the selected channel and plots them in the respective square. In summary, then:• The more closely the symbol plots are clustered at the center of each square, the better the performance of the QAM signal overall. As real-world perfection is not possible, a tight cluster close to the center generally represents the best performance possible.• If the amplitude of one or both signals deviates so much the original binary number is misinterpreted as another, bit errors occur. A constellation diagram that shows widely dispersed points indicates a signal where this is more likely to occur. A diagram with closely-clustered points indicates the opposite, where the reliability of the signal is strong and bit errors/ambiguities are less likely.• The overall amount of deviation from the ideal is a key factor in the calculation of MER. An MER measurement, therefore, is fundamentally a numerical summarization of a constellation graph.Figure 8-17 Symbol plot examplesAny nature of impairment (such as noise) can cause degradation of an amplitude-modulated symbol and cause scattered plots on a constellation graph. Certain types of impairments tend to show a recognizable signature on the graph. The following figures show some of these common impairments:Actual plotIdeal locationSymbol cluster on a good signalSymbol cluster on a poor signalPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-22Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsFigure 8-18 Common impairment signatures on the constellation graphThe first three normally indicate outside interference on the physical medium. A phase disturbance or mismatch between the I and Q signals is usually caused by a malfunction of the modulation equipment.8.8 System menu settings/controls (for RF)Under System > System/Module Settings > MoCA-RF Module > RF, the following areas are available that control RF module settings:•Download RF Channel Guide(s) on page 8-23•Thresholds on page 8-23•RF Script settings on page 8-26Moderate noise impairment Severe noise impairmentRF interference I/Q signal phase disturbancePreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-23IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs8.8.1 Download RF Channel Guide(s)(Select System > System/Module Settings > MoCA-RF Module > RF > Download RF Channel Guide(s))This function is used to transfer channel guide files from a remote computer to the unit using FTP. For more information, see:•Channel guide file format and general handling notes on page 8-23 for file format information•FTP connection parameters on page 2-59 for general tips on preparing for the FTP transactionFor general information about channel guide functionality, see Lineup tab on page 8-8.Channel guide file format and general handling notesA channel guide file must be in text-based comma-separated values (CSV) format, with four fields on each line representing the four columns shown in the Lineup tab (see Lineup tab on page 8-8). The following example shows the four supported types of entries for analog and digital channels, including out-of-band (OOB) channels:10,ABC,35,Analog11,NBC,36,64QAM12,CBS,37,256QAMOOB1,OutOfBand,OOB,QPSKNote that:• The fourth field (channel type) is case-sensitive and must be formatted exactly as shown.• The file must have a *.txt extension.For a sample channel guide file, please contact Spirent. Additionally, note the following about channel guide transfer:• On the FTP server computer, the file(s) to transfer must be placed in the folder associated with the FTP user account that you intend to use.• The FTP operation will transfer any file in the server folder with a *.txt extension. Therefore, any file you want to transfer must use that extension. If any filename in the server folder matches a file already on the unit, the file on the unit will be overwritten.8.8.2 Thresholds(Select System > System/Module Settings > MoCA-RF Module > RF > Thresholds)This screen provides access to:Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-24Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs•View/Edit Thresholds on page 8-24 - Allows you to view and edit individual thresholds on the unit•Download Thresholds on page 8-25 - Allows you to set all thresholds as a batch by importing a threshold settings fileView/Edit Thresholds(Select System > System/Module Settings > MoCA-RF Module > RF > Thresholds > View/Edit Thresholds)The settings in the Thresholds screen control the following:•The coloring of test results - Any individual result that violates its respective threshold is colored red•The overall pass/fail evaluation for a channel - For any channel tested, if any result threshold is violated, the channel test is considered a failure overallThe Thresholds screen allows two independent set of thresholds to be configured, labeled “TV/STB” and “ONT/Modem.” These labels are intended as a convenience for the common practice of maintaining two different threshold sets for testing at the respective locations. However, you may specify any applicable thresholds for either set and test with them at any location. For more information on specifying the threshold set to use during testing, see Channel Sweep Test setup on page 8-2 and Single Channel Test setup on page 8-4.For out-of-band (OOB) channels, the unit supports thresholds for minimum and maximum power levels only. For more information on OOB channels, see About out-of-band (OOB) channel support on page 8-18.Figure 8-19 Threshold screenPreliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-25IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsSome thresholds include both a minimum and maximum setting, while others a minimum or maximum only. For example, a BER threshold requires a maximum only, as the minimum value (that is, a “perfect” condition) is always zero.NOTE: If a threshold is not editable, it has been configured as such in the threshold file imported to the unit. For more information, see Download Thresholds on page 8-25.Download ThresholdsAs an alternative to editing thresholds directly on the unit, you can download a thresholds file to set all thresholds as a batch. This action completely overwrites all existing thresholds on the unit.For more information on the parameters required for the FTP transaction, see FTP connection parameters on page 2-59. The remainder of this section describes the required threshold file format.A threshold file uses a simple CSV format with lines in the following format:thld_name,TV_STB_value,ONT_Modem_valueFor example:Max Digital Power(dBmV),13,30Min Digital Power(dBmV),-6,7It must have the following filename:RFThresholds.datNote the following:• You should never change a threshold name (first field), otherwise the threshold will become unrecognizable and the unit will use a default instead.• You can precede any line with an exclamation point (!) to restrict the setting from editing onboard the unit, for example:!Min Digital Power(dBmV),13,30In this case, the minimum digital power will be viewable on the unit, but will not be editable. Note that this condition cannot be undone except by importing another thresholds file to the unit.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-26Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsSupported threshold ranges8.8.3 RF Script settings(Select System > System/Module Settings > RF Video Module > RF Script Settings)The settings in this area apply to the Close-Out Test Script (see Close-Out Test Script on page 8-10) and include:Table 8-2 General tabThreshold RangeMax Digital PowerMin Digital Power-30 to 30 dBmVMin 64-QAM MER 24 to 29 dBMin 256-QAM MER 28 to 33 dBMax Pre-FEC BERMax Post-FEC BER0.0000000010 to 0.001Max Analog Video PowerMin Analog Video Power-30 to 30 dBmVMinimum and maximum OOB channel power levels-35 to 35 dBmVSetting DescriptionClose-Out Saved Results FormatControls the format of the results file to be transferred from the unit, as follows:•XML-1 - Produces a results file in XML format that adheres to a Spirent-provided schema.•TXT - Produces a results file in a general text format without XML markup.Close-Out Test ChannelsChannels to test during each iteration of the script. Up to five channels may be specified and each channel must match a channel configured in the active channel guide, similar to the normal Channel Sweep test (see Lineup tab on page 8-8 and Download RF Channel Guide(s) on page 8-23).Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-27IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecsTable 8-3 FTP tab8.9 Supported channels and frequenciesThe module tuner supports the following EIA cable TV channels. Note that OOB channels are not listed:Setting DescriptionSystem NameA name under which all other FTP settings will be stored when you select Save. This feature is a convenience that allows you to store the profiles of multiple target servers and retrieve them later by selecting the name. To create a new profile, select [Create New] from the list and follow the prompts.Server IPPortUser IDPswdPing Before TransferInformation about the FTP server on the target computer, to which results are transferred following a script run. For more information, see FTP connection parameters on page 2-59.Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz) Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz)255.2500 59.7500 57.0000 81 565.2500 569.7500 567.0000361.2500 65.7500 63.0000 82 571.2500 575.7500 573.0000467.2500 71.7500 69.0000 83 577.2500 581.7500 579.0000577.2500 81.7500 79.0000 84 583.2500 587.7500 585.0000683.2500 87.7500 85.0000 85 589.2500 593.7500 591.00007175.2500 179.7500 177.0000 86 595.2500 599.7500 597.00008181.2500 185.7500 183.0000 87 601.2500 605.7500 603.00009187.2500 191.7500 189.0000 88 607.2500 611.7500 609.000010 193.2500 197.7500 195.0000 89 613.2500 617.7500 615.000011 199.2500 203.7500 201.0000 90 619.2500 623.7500 621.000012 205.2500 209.7500 207.0000 91 625.2500 629.7500 627.000013 211.2500 215.7500 213.0000 92 631.2500 635.7500 633.0000Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-28Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs14 121.2625 125.7625 123.0000 93 637.2500 641.7500 639.000015 127.2625 131.7625 129.0000 94 643.2500 647.7500 645.000016 133.2625 137.7625 135.0000 95 91.2500 95.7500 93.000017 139.2500 143.7500 141.0000 96 97.2500 101.7500 99.000018 145.2500 149.7500 147.0000 97 103.2500 107.7500 105.000019 151.2500 155.7500 153.0000 98 109.2750 113.7750 111.000020 157.2500 161.7500 159.0000 99 115.2750 119.7750 117.000021 163.2500 167.7500 165.0000 100 649.2500 653.7500 651.000022 169.2500 173.7500 171.0000 101 655.2500 659.7500 657.000023 217.2500 221.7500 219.0000 102 661.2500 665.7500 663.000024 223.2500 227.7500 225.0000 103 667.2500 671.7500 669.000025 229.2625 233.7625 231.0000 104 673.2500 677.7500 675.000026 235.2625 239.7625 237.0000 105 679.2500 683.7500 681.000027 241.2625 245.7625 243.0000 106 685.2500 689.7500 687.000028 247.2625 251.7625 249.0000 107 691.2500 695.7500 693.000029 253.2625 257.7625 255.0000 108 697.2500 701.7500 699.000030 259.2625 263.7625 261.0000 109 703.2500 707.7500 705.000031 265.2625 269.7652 267.0000 110 709.2500 713.7500 711.000032 271.2625 275.7625 273.0000 111 715.2500 719.7500 717.000033 277.2625 281.7625 279.0000 112 721.2500 725.7500 723.000034 283.2625 287.7625 285.0000 113 727.2500 731.7500 729.000035 289.2625 293.7625 291.0000 114 733.2500 737.7500 735.000036 295.2625 299.7625 297.0000 115 739.2500 743.7500 741.000037 301.2625 305.7625 303.0000 116 745.2500 749.7500 747.000038 307.2625 311.7625 309.0000 117 751.2500 755.7500 753.000039 313.2625 317.7625 315.0000 118757.2500 761.7500 759.000040 319.2625 323.7625 321.0000 119 763.2500 767.7500 765.0000Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz) Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz)Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 8-29IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs41 325.2625 329.7625 327.0000 120 769.2500 773.7500 771.000042 331.2750 335.7750 333.0000 121 775.2500 779.7500 777.000043 337.2625 341.7625 339.0000 122 781.2500 785.7500 783.000044 343.2625 347.7625 345.0000 123 787.2500 791.7500 789.000045 349.2625 353.7625 351.0000 124 793.2500 797.7500 795.000046 355.2625 359.7625 357.0000 125 799.2500 803.7500 801.000047 361.2625 365.7625 363.0000 126 805.2500 809.7500 807.000048 367.2625 371.7625 369.0000 127 811.2500 815.7500 813.000049 373.2625 377.7625 375.0000 128 817.2500 821.7500 819.000050 379.2625 383.7625 381.0000 129 823.2500 827.7500 825.000051 385.2625 389.7625 387.0000 130 829.2500 833.7500 831.000052 391.2625 395.7625 393.0000 131 835.2500 839.7500 837.000053 397.2625 401.7625 399.0000 132 841.2500 845.7500 843.000054 403.2500 407.7500 405.0000 133 847.2500 851.7500 849.000055 409.2500 413.7500 411.0000 134 853.2500 857.7500 855.000056 415.2500 419.7500 417.0000 135 859.2500 863.7500 861.000057 421.2500 425.7500 423.0000 136 865.2500 869.7500 867.000058 427.2500 431.7500 429.0000 137 871.2500 875.7500 873.000059 433.2500 437.7500 435.0000 138 877.2500 881.7500 879.000060 439.2500 443.7500 441.0000 139 883.2500 887.7500 885.000061 445.2500 449.7500 447.0000 140 889.2500 893.7500 891.000062 451.2500 455.7500 453.0000 141 895.2500 899.7500 897.000063 457.2500 461.7500 459.0000 142 901.2500 905.7500 903.000064 463.2500 467.7500 465.0000 143 907.2500 911.7500 909.000065 469.2500 473.7500 471.0000 144 913.2500 917.7500 915.000066 475.2500 479.7500 477.0000 145 919.2500 923.7500 921.000067 481.2500 485.7500 483.0000 146 925.2500 929.7500 927.0000Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz) Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz)Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 8-30Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs68 487.2500 491.7500 489.0000 147 931.2500 935.7500 933.000069 493.2500 497.7500 495.0000 148 937.2500 941.7500 939.000070 499.2500 503.7500 501.0000 149 943.2500 947.7500 945.000071 505.2500 510.7500 508.0000 150 949.2500 953.7500 951.000072 511.2500 515.7500 513.0000 151 955.2500 959.7500 957.000073 517.2500 521.7500 519.0000 152 961.2500 965.7500 963.000074 523.2500 527.7500 525.0000 153 967.2500 971.7500 969.000075 529.2500 533.7500 531.0000 154 973.2500 977.7500 975.000076 535.2500 539.7500 537.0000 155 979.2500 983.7500 981.000077 541.2500 545.7500 543.0000 156 985.2500 989.7500 987.000078 547.2500 551.7500 549.0000 157 991.2500 995.7500 993.000079 553.2500 557.7500 555.0000 158 997.2500 1001.7500999.000080 559.2500 563.7500 561.0000Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz) Ch. # A. video (MHz)A. audio (Mhz)Digital (MHz)Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 9-19: SpecificationsThis section provides detailed information on physical components and specifications of the Tech-X Flex base unit and modules. Note that:• Specifications are subject to change.• If the unit produces a measurement that is beyond a range shown in these specifications, it should be considered generally valid but not necessarily within the stated accuracy.9.1 General unit specificationsTable 9-1 Physical specificationsDimensions (H x W x D) • 8.964 in x 4.208 in x 2.524 in• 22.77 cm x 10.69 cm x 6.41 cmWeight 2.0 lb. (0.91 kg) Display Color LCD with adjustable backlight. 640x480 pixels (VGA)Case material BAYBLEND FR-3000 HI ABS + PC (POLYCARBONATE)Rubber components TPU (DESMOPAN 9370A)LED indicators Sync, Data, Errors, ChargeCommunications interfaces• 10/100/1G Base-T Ethernet• IEEE 802.11b/g/n/ac (“Wireless B”, “Wireless G”, “Wireless N”, and “Wireless AC”) Wi-Fi• USB 2.0Test interfaces • 10/100/1G Base-T (x2)• 802.11b/g/n/ac (wireless)Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 9-2Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsTable 9-2 Power specificationsTable 9-3 Environmental requirements9.2 Wi-Fi functional area specificationsTable 9-4 Wi-Fi specificationsAC operations Requires external AC adapter/charger. Adapter will charge battery while unit is in use. Adapter specifications:•Input - 100 to 240 VAC, 50/60 Hz, 0.8 amps•Output - 12 VDC, 2.0 ampsBattery type Lithium-ion rechargeable, replacements available from SpirentBattery life 3-10 hours, depending on use and type of module attachedBattery recharge time 3-4 hoursMaximum power usage 24 wattsMaximum heat dissipation9 wattsOperating temperature -0.4 to 131°F (-18 to 55°C)Storage temperature -4 to 158°F (-20 to 70°C)Humidity tolerance 5 to 85% RH at +104°F (40°C)Drop IEC 60068, 68-2-32Protocol support 802.11b/g/n/ac with WEP, WPS, WPA, or WPA2 security.Antennas •T5200 - Two internal 802.11b/g/n antennas and three internal 802.11ac antennas.•T5300 - Three internal antennas for all Wi-Fi testing (b/g/n/ac), one internal antenna for Wi-Fi admin, and one internal antenna reserved for spectrum testing.Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 9-3IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs9.3 RF functional area specificationsTable 9-5 RF functional area specificationsFrequency (with latest hardware)For ATSC 6 GHz channels:•Tuning range: 50 to 1002 MHz•Tuning resolution: 62.5 kHz•Channel bandwidth: 6 MHzFor 8 GHz channels:•Tuning range: 50 to 860 MHz•Tuning resolution: 62.5 kHz•Channel bandwidth: 8 MHzAnalog measurements•Power measurement range: -30 to +30 dBmV. For additional information, see Bar graph and power measurement notes on page 8-13.•Power level accuracy (audio and video): +/-1.5 dB•Channel support: EIA/NTSC channels 2 through 135•Other supported measurements:– Carrier-to-noise ratio– Audio-to-video ratioDigital measurements•Power measurement range: -30 to +30 dBmV. For additional information, see Bar graph and power measurement notes on page 8-13.•Power level accuracy (multiplex): +/-2.0 dB•QAM support: 64-QAM and 256-QAM•MER range–64-QAM: 15 to 40 dB–256-QAM: 21 to 40 dB•MER accuracy: +/-2.0 dB•BER resolution: Up to 10e-05 (1 error per 100,000 bits) for a single measurement interval. For tests that make repeated measurements, this resolution increases indefinitely as the data from additional sample periods is added.•Other supported measurements:– Peak-to-valley ratio– Constellation diagramPreliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 9-4Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF Specs9.4 MoCA functional area specificationsTable 9-6 MoCA functional area specifications9.5 MoCA/RF module complianceUL® /CSA®61010-1 - Safety Requirements For Electrical Equipment For Measurement, Control, and Laboratory Use9.6 FCC compliance statements•RF exposure - This equipment complies with the FCC RF radiation exposure limits set forth for an uncontrolled environment. For wireless 802.11b/g/n operation, the highest specific absorption rate (SAR) value is 0.787 W/kg. Special considerations for 802.11ac transmission apply - see Important wireless 802.11ac note (T5100 models only) on page 3-2.•Co-location - This transmitter must not be co-located or operated in conjunction with any other antenna or transmitter.•Compliance - This device complies with Part 15 of FCC rules. Operation is subject to the following two conditions:1 This device may not cause harmful interference and,2 This device must accept any interference received, including interference that may cause undesired operation.•Operation and installation - This equipment has been tested and found to comply with limits defined by part 15 of FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the manufacturer documentation, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his/her own expense.•Modifications - Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.MoCA standard support MoCA 1.0, 1.1, and 2.0Preliminary issue - Limited distribution only!
Tech-X Flex® (NG2) Tech-X Flex User Guide - Firmware v06.50 9-5IntroOverviewWi-FiEthernetSystemIP/VideoMoCARFSpecs9.7 IC compliance statementsThis device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of the device.Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'exploitation est autorisée aux deux conditions suivantes : (1) l'appareil ne doit pas produire de brouillage, et (2) l'utilisateur de l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le fonctionnement.Preliminary issue - Limited distribution only!
Tech-X Flex User Guide - Firmware v06.50 Tech-X Flex® (NG2) 9-6Intro Overview Wi-Fi Ethernet System IP/Video MoCA RF SpecsPreliminary issue - Limited distribution only!
Preliminary issue - Limited distribution only!

Navigation menu