Cisco Linksys WRT51AB Dual Band Wireless A+B Broadband Router User Manual WRT51AB user guide 12

Cisco-Linksys, LLC Dual Band Wireless A+B Broadband Router WRT51AB user guide 12

Contents

Manual Part 2

Dual-Band Wireless A+B Broadband Router DTIM Interval This value, between 1 and 16384, indicates the interval of theDelivery Traffic Indication Message (DTIM). A DTIM field is a countdownfield informing clients of the next window for listening to broadcast and mul-ticast messages. When the Router has buffered broadcast or multicast messagesfor associated clients, it sends the next DTIM with a DTIM Interval value. Itsclients hear the beacons and awaken to receive the broadcast and multicast mes-sages. The default value is 1.RTS Threshold Should you encounter inconsistent data flow, only minorreduction of the default value, 2346, is recommended. If a network packet issmaller than the preset RTS threshold size, the RTS/CTS mechanism will notbe enabled. The Router sends Request to Send (RTS) frames to a particularreceiving station and negotiates the sending of a data frame. After receiving anRTS, the wireless station responds with a Clear to Send (CTS) frame toacknowledge the right to begin transmission. The RTS Threshold value shouldremain at its default value of 2346. Fragmentation Threshold This value specifies the maximum size for a pack-et before data is fragmented into multiple packets. If you experience a highpacket error rate, you may slightly increase the Fragmentation Threshold.Setting the Fragmentation Threshold too low may result in poor network per-formance. Only minor reduction of the default value is recommended. In mostcases, it should remain at its default value of 2346. Transmission Rate The rate of data transmission should be set depending onthe speed of your wireless network. You can select from a range of transmissionspeeds (6, 9, 12, 18, 24, 36, 48, or 54Mbps), or you can select Best to have theRouter automatically use the fastest possible data rate and enable the Auto-Fallback feature. Auto-Fallback will negotiate the best possible connectionspeed between the Router and a wireless client. The default value is Best.Transmit Power The greater the transmit power used, the larger the area awireless network covers. To minimize the likelihood of eavesdropping by unau-thorized wireless users, do not use more transmit power than necessary to coverthe range needed for your wireless network. Try using the Router at differentlevels of transmit power, and determine how much transmit power is needed toreach the wireless client, such as a PC, or access point that is farthest from theRouter. Then select the appropriate level of transmit power (Full, Half,Quarter, Eighth, or Min) from the drop-down menu. The default value is Full.49Instant Wireless®SeriesThe Advanced Wireless screen allows you to customize data transmission set-tings and access the 802.1x Configuration screen. In most cases, the advancedwireless settings on this screen should remain at their default values.5GHz, 802.11aBeacon Interval The Beacon Interval value indicates the frequency interval ofthe beacon. Enter a value between 20 and 1000. A beacon is a packet broadcastby the Router to synchronize the wireless network. The default value is 100.48Advanced WirelessFigure 6-19
Dual-Band Wireless A+B Broadband Router 802.1x ConfigurationThe 802.1x Configuration screen allows you to alter the 802.1x settings foryour wireless network(s). Based on the Extensible Authentication Protocol(EAP), the 802.1x standard specifies an authentication framework for awireless client to access a network, so network security is enhanced.To access a network with 802.1x enabled, wireless clients, such as PCs,must use 802.1x client software or Windows XP, which supports 802.1x. 51Instant Wireless®Series2.4GHz, 802.11bBeacon Interval The Beacon Interval value indicates the frequency interval ofthe beacon. Enter a value between 20 and 1000. A beacon is a packet broadcastby the Router to synchronize the wireless network. The default value is 100.RTS Threshold Should you encounter inconsistent data flow, only minorreduction of the default value, 2346, is recommended. If a network packet issmaller than the preset RTS threshold size, the RTS/CTS mechanism will notbe enabled. The Router sends Request to Send (RTS) frames to a particularreceiving station and negotiates the sending of a data frame. After receiving anRTS, the wireless station responds with a Clear to Send (CTS) frame toacknowledge the right to begin transmission. The RTS Threshold value shouldremain at its default value of 2346. Fragmentation Threshold This value specifies the maximum size for a pack-et before data is fragmented into multiple packets. If you experience a highpacket error rate, you may slightly increase the Fragmentation Threshold.Setting the Fragmentation Threshold too low may result in poor network per-formance. Only minor reduction of this value is recommended. In most cases,it should remain at its default value of 2346. Preamble Type The preamble defines the length of the CRC block for com-munication between the Router and a roaming wireless network adapter. Selectthe appropriate preamble type for your wireless network. (High network trafficareas should use the shorter preamble type.) The default is Long Preamble.Transmission Rate The rate of data transmission should be set depending onthe speed of your wireless network. You can select from a range of transmissionspeeds (1, 2, 5.5, or 11Mbps), or you can select Best to have the Router auto-matically use the fastest possible data rate and enable the Auto-Fallback fea-ture. Auto-Fallback will negotiate the best possible connection speed betweenthe Router and a wireless client. The default setting is Best.To apply any of the settings you change on this page, click the Apply button. Tocancel any changes you’ve entered on this page, click the Cancel button. To getmore information about the features, click the Help button.802.1x Configuration802.1x Configuration Click the 802.1x Configuration button to customizethe Router’s 802.1x feature (see Figure 6-20). 50Figure 6-20Note: If your wireless network does not have a RADIUS server, the802.1x feature is not applicable to your network. (802.1x is anadvanced data security measure and not essential for router operation.)Note: For more details about 802.1x, refer to “Appendix C:Configuring Wireless Security.”
Dual-Band Wireless A+B Broadband Router 53Instant Wireless®SeriesRADIUS ServerThe Router’s 802.1x feature works with a RADIUS server. It may also workwith other types of authentication servers, depending on the specifics ofeach authentication server. RADIUS Server IP Address Enter the IP Address of the RADIUS server inthe field provided.RADIUS Server Port Enter the Port Number of the RADIUS server in thefield provided. The default is 1812.Shared Secret Enter the Shared Secret Key used by the Router andRADIUS server during the authentication process.5GHz, 802.11aDisable/EAP-MD5/EAP-TLS/TTLS Select EAP-MD5 to enable use of802.1x with MD5 authentication for the 5GHz, 802.11a network connectionbetween a wireless client and a RADIUS server (the Router acts as anauthenticator). Select EAP-TLS/TTLS to enable use of 802.1x with TLS orTTLS authentication for the 5GHz, 802.11a network connection between awireless client and a RADIUS server (the Router acts as an authenticator).To disable 802.1x authentication for your 5GHz, 802.11a network, keep thedefault setting, Disable. WEP Settings If you are using 802.1x with MD5 authentication, then youmust click the WEP Settings button and set up a static key for WEPencryption. This static key must be set on the Router’s 5GHz, 802.11a WEPSettings screen and on all 5GHz, 802.11a wireless clients. 52Dynamic WEP Key Length When 5GHz, 802.11a wireless clients are usingcertificate-based authentication (EAP-TLS or EAP-TTLS), dynamic WEPkeys are automatically generated. Select the length of the Dynamic Key (64or 128-bit) from the drop-down menu.Key Renewal Timeout If you are using dynamic WEP keys (available onlyfor EAP-TLS or EAP-TTLS authentication), enter the number of secondsthat will elapse before the Dynamic Key automatically changes. The defaultis 300 seconds.Port Inactivity Timeout After the wireless client has been authenticated, theRouter monitors activity on the port being used. In the Port InactivityTimeout field, enter the number of seconds the port can be inactive beforethe client automatically forced to reauthenticate. The default is 600 seconds.Port Connectivity Timeout After the Router requests the identity of a wire-less client, the client must respond with an identity message within a cer-tain length of time. In the Port Connectivity Timeout field, enter the numberof seconds the client has to respond within before the connection is termi-nated. The default is 300 seconds.2.4GHz, 802.11bDisable/EAP-MD5/EAP-TLS/TTLS Select EAP-MD5 to enable use of802.1x with MD5 authentication for the 2.4GHz, 802.11b network connec-tion between a wireless client and a RADIUS server (the Router acts as anauthenticator). Select EAP-TLS/TTLS to enable use of 802.1x with TLS orTTLS authentication for the 2.4GHz, 802.11b network connection betweena wireless client and a RADIUS server (the Router acts as an authenticator).To disable 802.1x authentication for your 2.4GHz, 802.11b network, keepthe default setting, DisableWEP Settings If you are using 802.1x with MD5 authentication, then youmust click the WEP Settings button and set up a static key for WEPencryption. This static key must be set on the Router’s 2.4GHz, 802.11bWEP Settings screen and on all 2.4GHz, 802.11b wireless clients. Note: Using MD5 authentication is less secure than using certificate-based authentication (TLS or TTLS), because keys are not changedautomatically.Important: The Router’s 802.1x feature works with Windows XP.It may also work with other Windows operating systems, depend-ing on the specifics of your PC’s operating system and the 802.1xclient software being used.Note: Many authentication methods work within the 802.1x frame-work. The Router supports MD5 and certificate-based (TLS or TTLS)authentication methods. Using MD5 authentication is less secure thanusing certificate-based authentication (TLS or TTLS), because keysare not changed automatically.
Dual-Band Wireless A+B Broadband Router The Filters screen allows you to block specific internal users from accessingthe Internet. You can set up filters by using MAC addresses, IP addresses, ornetwork port numbers (or a range of ports).Filtered Private Port Range To filter users by network port number, selectBoth, TCP, or UDP, depending on which protocols you want to filter. Thenenter the port numbers you want to filter into the port number fields. Usersconnected to the Router will no longer be able to access any port number list-ed there. To disable a filter, select Disable.55Instant Wireless®SeriesDynamic WEP Key Length When 2.4GHz, 802.11b wireless clients areusing certificate-based authentication (EAP-TLS or EAP-TTLS), dynamicWEP keys are automatically generated. Select the length of the DynamicKey (64 or 128-bit) from the drop-down menu.Key Renewal Timeout If you are using dynamic WEP keys (available onlyfor EAP-TLS or EAP-TTLS authentication), enter the number of secondsthat will elapse before the Dynamic Key automatically changes. The defaultis 300 seconds.Port Inactivity Timeout After the wireless client has been authenticated, theRouter monitors activity on the port being used. In the Port InactivityTimeout field, enter the number of seconds the port can be inactive beforethe client automatically forced to reauthenticate. The default is 600 seconds.Port Connectivity Timeout After the Router requests the identity of a wire-less client, the client must respond with an identity message within a cer-tain length of time. In the Port Connectivity Timeout field, enter the numberof seconds the client has to respond within before the connection is termi-nated. The default is 300 seconds.To apply any of the settings you change on this page, click the Apply button. Tocancel any changes you’ve entered on this page, click the Cancel button. To getmore information about the features, click the Help button.54FiltersFigure 6-21
Dual-Band Wireless A+B Broadband Router 57Instant Wireless®Series56If you want to enter more than ten MAC addresses, select MAC Addresses 1-10, 11-20, 21-30, 31-40, or 41-50 from the drop-down menu to enter addition-al MAC addresses, up to a maximum of 50. Then click the Apply button to savethe MAC addresses.To disable Private MAC Filtering, select Disable.Block WAN Request By enabling the Block WAN Request feature, you canprevent your network from being “pinged,” or detected, by other Internet users.The Block WAN Request feature also reinforces your network security by hid-ing network ports. Both functions of the Block WAN Request feature make itmore difficult for outside users to work their way into your network. Thedefault is Enable.IPSec Pass-Through The Router supports IPSec Pass-Through. InternetProtocol Security (IPSec) is a suite of protocols used to implement secureexchange of packets at the IP layer, and it is one of the methods used to enableVirtual Private Networking (VPN) tunnels. IPSec is more secure than PPTP.The default is Enable.PPTP Pass-Through The Router supports PPTP Pass-Through. Point-to-PointTunneling Protocol (PPTP) is one of the methods used to enable VPN tunnels.PPTP is less secure than IPSec. The default is Enable.Remote Management This feature allows you to manage the Router from aremote location, via the Internet. To enable this feature, select Enable, and usethe specified port (default is 8080) on your PC to remotely manage the Router.The default is Disable.MTU MTU is the Maximum Transmission Unit. It specifies the largest pack-et size permitted for network transmission. To use this feature, select Enable,and enter the value desired. You should leave this value in the 572 to 1492range. The default is Disable.To apply any of the settings you change on this page, click the Apply button. Tocancel any changes you’ve entered on this page, click the Cancel button. To getmore information about the features, click the Help button.Private IP Filter To set up a filterusing IP addresses, select Enable.Then select Only Allow InternetAccess for the IP Addresses on theList or Only Deny Internet Access forthe IP Addresses on the List. Click the Edit IP Filter List button.Enter the appropriate IP addresses intothe IP address fields (see Figure 6-22).Each IP address should be entered inthis format: xxx.xxx.xxx.xxx (the x’srepresent the actual digits of the IPaddress). If you want to enter more than ten IPaddresses, select IP Addresses 1-10,11-20, 21-30, 31-40, or 41-50 from thedrop-down menu to enter additional IPaddresses, up to a maximum of 50.Then click the Apply button to save theIP addresses.To disable Private IP Filtering, select Disable.Private MAC Filter To set up a filterusing MAC addresses, select Enable.Then select Only Allow InternetAccess for the MAC Addresses onthe List or Only Deny Internet Accessfor the IP Addresses on the List.Click the Edit MAC Filter List but-ton. Enter the appropriate MACaddresses into the MAC address fields(see Figure 6-23). Each MAC addressshould be entered in this format:xx:xx:xx:xx:xx:xx (the x’s representthe actual characters of the MACaddress).Figure 6-22Figure 6-23
Dual-Band Wireless A+B Broadband Router TCP Protocol Click this checkbox if you want to forward the data transmis-sions that use the TCP protocol.UDP Protocol Click this checkbox if you want to forward the data transmis-sions that use the UDP protocol.IP Address For each application, enter the IP Address of the PC running thespecific application.Enable Click the Enable checkbox to enable port forwarding for the relevantapplication.The following table shows the typical port forwarding settings for commonInternet applications.To apply any of the settings you change on this page, click the Apply button. Tocancel any changes you’ve entered on this page, click the Cancel button. To getmore information about the features, click the Help button.59Instant Wireless®Series58FTPApplications External Port TCP Protocol UDP Protocol21Telnet 23SMTP 25DNS 53TFTP 69Finger 79HTTP 80POP3 110NNTP 119SNMP 161The Port Forwarding screen sets up public services on your network, such asweb servers, ftp servers, e-mail servers, or other specialized Internet applica-tions. (Specialized Internet applications are any applications that use Internetaccess to perform functions such as videoconferencing or online gaming. SomeInternet applications may not require any forwarding.)Customized Applications In the field provided, enter the name you wish togive each application.External Port For each application, enter the number of the External Ports(the port numbers seen by users on the Internet) in the appropriate fields. (Tofind out the port range, check your application’s documentation.) If there isonly one External Port, enter its number in both External Port fields.Port ForwardingFigure 6-24Note: Any PC whose port is being forwarded should have its DHCPclient function disabled and a new static IP address assigned to itbecause its IP address may change when using the DHCP function.
Dual-Band Wireless A+B Broadband Router 61Instant Wireless®Series602. If you selected the Gateway mode, click the Apply button. If you selectedthe Router mode, proceed to step 3.3. For Dynamic Routing, the default is Enable. The Dynamic Routing featureenables the Router to automatically adjust to physical changes in the net-work’s layout and exchange routing tables with the other router(s). TheRouter determines the network packets’ route based on the fewest numberof hops between the source and the destination. Select Disable to disablethe Dynamic Routing feature for data transmissions.4. To set up a static route between the Router and another network, select anumber from the Static Routing drop-down list. (A static route is a pre-determined pathway that network information must travel to reach a spe-cific host or network.)5. Enter the following data:• Destination LAN IP - The Destination LAN IP is the address of theremote network or host to which you want to assign a static route.• Subnet Mask - The Subnet Mask determines which portion of aDestination LAN IP address is the network portion, and which portionis the host portion. • Default Gateway - This is the IP address of the gateway device thatallows for contact between the Router and the remote network or host.6. To cancel your changes, click the Cancel button. To save your changes,click the Apply button. To get more information about the features, clickthe Help button.To delete a static route entry:1. From the Static Routing drop-down list, select the entry number of the stat-ic route.2. Click the Delete This Entry button.3. To cancel a deletion, click the Cancel button. To save a deletion, click theApply button. To get more information about the features, click the Helpbutton.On the Routing screen, you can set the routing mode of the Router. Gatewaymode is recommended for most users. To set up routing:1. Choose the correct working mode. Select Gateway if the Router is hostingyour network’s connection to the Internet (recommended for most users).Select Router if the Router exists on a network with other routers.RoutingFigure 6-25Note: The Routing screen and available features will vary dependingon which mode you select.Note: If you have more than one router on your network, you shouldselect Router for the working mode.
Dual-Band Wireless A+B Broadband Router 63Instant Wireless®Series62The DMZ Host screen lets you enable the DMZ hosting feature, which allowsone local user to be exposed to the Internet for use of a special-purpose serv-ice such as Internet gaming or videoconferencing. Whereas port forwardingcan only forward a maximum of ten port ranges, DMZ hosting forwards all theports to one PC simultaneously. It is recommended to use Port Forwardingwhenever possible because it is more secure.To expose one PC to the Internet:1. Click the Enable radio button.2. Enter the computer’s IP address in the DMZ Host IP Address field.3. To cancel your changes, click the Cancel button. To save your new settings,click the Apply button. To get more information about the features, clickthe Help button.Note: Any PC whose ports are being forwarded should have its DHCPclient function disabled and a new static IP address assigned to itbecause its IP address may change when using the DHCP client function.DMZ HostFigure 6-27Show Routing Table Click the Show Routing Table button to view all of thevalid dynamic and static route entries in use (see Figure 6-26). The DestinationLAN IP address, Subnet Mask, Gateway, and Interface information are dis-played for each entry. Click the Refresh button to display the most up-to-datedata.Figure 6-26
Dual-Band Wireless A+B Broadband Router 65Instant Wireless®Series64If you do not know your adapter’s MAC address, follow these instructions:1. Click the Start button, and select Run.2. Enter command in the field provided, and press the OK button.3. At the command prompt, enter ipconfig /all. Then press the Enter key.4. Write down your adapter’s physical address; it is the adapter’s MACaddress.On the MAC Address Clone screen, you can clone the MAC address of yourPC’s network adapter onto the Router. A MAC address is a 12-digit code assigned to a unique piece of hardware foridentification, like a social security number. Some ISPs require that you regis-ter the MAC address of your PC’s network adapter, which was connected toyour cable or DSL modem during installation. To avoid calling your ISP andchanging the MAC address that is registered with the ISP, follow these instruc-tions:1. Click the Enable radio button.2. Enter your adapter’s MAC address in the User Defined Internet MACAddress field.3. To cancel your changes, click the Cancel button. To save your new settings,click the Apply button. To get more information about the features, clickthe Help button.To disable MAC address cloning, click the Disable radio button.MAC Address CloneFigure 6-28
Dual-Band Wireless A+B Broadband Router For Windows 2000:A. Click Start, Settings, and Control Panel. Double-click Network andDial-Up Connections.B. Right-click the Local Area Connection that is associated with the Ethernetadapter you are using, and select the Properties option.C. In the Components checked are used by this connection box, highlightInternet Protocol (TCP/IP), and click the Properties button. Select Usethe following IP address option.D. Enter a unique IP address that is not used by any other computer on thenetwork connected to the Router. You can only use an IP address in theranges 192.168.1.2 to 192.168.1.99 and 192.168.1.151 to 192.168.1.254. E. Enter the Subnet Mask, 255.255.255.0.F. Enter the Default Gateway, 192.168.1.1 (Router’s default IP address).G. Toward the bottom of the window, select Use the following DNS serveraddresses, and enter the Preferred DNS server and Alternative DNSserver (provided by your ISP). Contact your ISP or go on its website to findthe information.H. Click the OK button in the Internet Protocol (TCP/IP) Properties window,and click the OK button in the Local Area Connection Properties window.I. Restart the computer if asked.For Windows NT 4.0:A. Click Start, Settings, and Control Panel. Double-click the Network icon.B. Click the Protocol tab, and double-click TCP/IP Protocol.C. When the window appears, make sure you have selected the correctAdapter for your Ethernet adapter.D. Select Specify an IP address, and enter a unique IP address that is notused by any other computer on the network connected to the Router. Youcan only use an IP address in the ranges 192.168.1.2 to 192.168.1.99 and192.168.1.151 to 192.168.1.254.E. Enter the Subnet Mask, 255.255.255.0.F. Enter the Default Gateway, 192.168.1.1 (Router’s default IP address).G. Click the DNS tab, and enter the Host and Domain names (e.g., John forHost and home for Domain). Under DNS Service Search Order, click theAdd button. Enter the DNS IP address in the DNS Server field, and clickthe Add button. Repeat this action for all DNS IP addresses given by yourISP.H. Click the OK button in the TCP/IP Protocol Properties window, and clickthe Close button in the Network window.I. Restart the computer if asked.67Instant Wireless®Series66Appendix A:TroubleshootingThis appendix consists of two parts: “Common Problems and Solutions” and“Frequently Asked Questions.” Provided are possible solutions to problems thatmay occur during the installation and operation of the Router. Read the descrip-tions below to help solve your problems. If you can’t find an answer here, checkthe Linksys website at www.linksys.com.1. I need to set a static IP address on a PC.The Router, by default, assigns an IP address range of 192.168.1.100 to192.168.1.150 using the DHCP server on the Router. To set a static IP address,you can only use the ranges 192.168.1.2 to 192.168.1.99 and 192.168.1.151 to192.168.1.254. Each PC or network device that uses TCP/IP must have aunique address to identify itself in a network. If the IP address is not unique toa network, Windows will generate an IP conflict error message. You can assigna static IP address to a PC by performing the following steps:For Windows 98 and Me:A. Click Start, Settings, and Control Panel. Double-click Network.B. In The following network components are installed box, select the TCP/IP->associated with your Ethernet adapter. If you only have one Ethernet adapterinstalled, you will only see one TCP/IP line with no association to an Ethernetadapter. Highlight it and click the Properties button.C. In the TCP/IP properties window, select the IP address tab, and selectSpecify an IP address. Enter a unique IP address that is not used by anyother computer on the network connected to the Router. You can only usean IP address in the ranges 192.168.1.2 to 192.168.1.99 and 192.168.1.151to 192.168.1.254. Make sure that each IP address is unique for each PC ornetwork device.D. Click the Gateway tab, and in the New Gateway prompt, enter 192.168.1.1,which is the default IP address of the Router. Click the Add button to acceptthe entry.E. Click the DNS tab, and make sure the DNS Enabled option is selected.Enter the Host and Domain names (e.g., John for Host and home forDomain). Enter the DNS entry provided by your ISP. If your ISP has notprovided the DNS IP address, contact your ISP to get that information or goto its website for the information.F. Click the OK button in the TCP/IP properties window, and click Close orthe OK button for the Network window.G. Restart the computer when asked.Common Problems and Solutions
Dual-Band Wireless A+B Broadband Router 69Instant Wireless®Series68B. Open a command prompt.• For Windows 98 and Me, please click Start and Run. In the Open field,type in command. Press the Enter key or click the OK button.• For Windows NT, 2000, and XP, please click Start and Run. In theOpen field, type cmd. Press the Enter key or click the OK button.C. In the command prompt, type ping 192.168.1.1 and press the Enter key. • If you get a reply, the computer is communicating with the Router.• If you do NOT get a reply, please check the cable, and make sure Obtainan IP address automatically is selected in the TCP/IP settings for yourEthernet adapter. D. In the command prompt, type ping followed by your Internet or WAN IPaddress and press the Enter key. The Internet or WAN IP Address can befound on the Status screen of the Router’s web-based utility. For example,if your Internet or WAN IP address is 1.2.3.4, you would enter ping 1.2.3.4and press the Enter key.• If you get a reply, the computer is connected to the Router.• If you do NOT get a reply, try the ping command from a different com-puter to verify that your original computer is not the cause of the problem.E. In the command prompt, type ping www.yahoo.com and press the Enterkey. • If you get a reply, the computer is connected to the Internet. If you can-not open a webpage, try the ping command from a different computer toverify that your original computer is not the cause of the problem.• If you do NOT get a reply, there may be a problem with the connection.Try the ping command from a different computer to verify that your orig-inal computer is not the cause of the problem.3. I am not getting an IP address on the Internet with my Internet connection.A. Refer to “Problem #2, I want to test my Internet connection” to verify thatyou have connectivity.B. If you need to register the MAC address of your Ethernet adapter with yourISP, please see “Appendix D: Finding the MAC address and IP Address forYour Ethernet Adapter.” If you need to clone the MAC address of yourEthernet adapter onto the Router, see the MAC Address Clone section of“Chapter 6: The Router’s Web-based Utility” for details.C. Make sure you are using the right Internet connection settings. Contact yourISP to see if your Internet connection type is DHCP, Static IP Address, orPPPoE (commonly used by DSL consumers). Please refer to the Setup sec-tion of “Chapter 6: The Router’s Web-based Utility” for details on Internetconnection settings.For Windows XP:The following instructions assume you are running Windows XP with thedefault interface. If you are using the Classic interface (where the icons andmenus look like previous Windows versions), please follow the instructions forWindows 2000.A. Click Start and Control Panel. B. Click the Network and Internet Connections icon and then the NetworkConnections icon.C. Right-click the Local Area Connection that is associated with the Ethernetadapter you are using, and select the Properties option.D. In the This connection uses the following items box, highlight InternetProtocol (TCP/IP). Click the Properties button.E. Enter a unique IP address that is not used by any other computer on the net-work connected to the Router. You can only use an IP address in the ranges192.168.1.2 to 192.168.1.99 and 192.168.1.151 to 192.168.1.254. F. Enter the Subnet Mask, 255.255.255.0.G. Enter the Default Gateway, 192.168.1.1 (Router’s default IP address).H. Toward the bottom of the window, select Use the following DNS serveraddresses, and enter the Preferred DNS server and Alternative DNSserver (provided by your ISP). Contact your ISP or go on its website to findthe information.I. Click the OK button in the Internet Protocol (TCP/IP) Properties window.Click the OK button in the Local Area Connection Properties window.2. I want to test my Internet connection.A. Check your TCP/IP settings. For Windows 98, Me, 2000, and XP:Refer to “Chapter 4: Configure the PCs” for details. Make sure Obtain IPaddress automatically is selected in the settings.For Windows NT 4.0:• Click Start, Settings, and Control Panel. Double-click the Networkicon.• Click the Protocol tab, and double-click on TCP/IP Protocol.• When the window appears, make sure you have selected the correctAdapter for your Ethernet adapter and set it for Obtain an IP addressfrom a DHCP server.• Click the OK button in the TCP/IP Protocol Properties window, andclick the Close button in the Network window.• Restart the computer if asked.
Dual-Band Wireless A+B Broadband Router of the web interface. If you assigned a static IP address to any computer or net-work device on the network, you need to change its IP address accordingly to192.168.2.Y (Y being any number from 1 to 254). Note that each IP addressmust be unique within the network.Your VPN may require port 500/UDP packets to be passed to the computer thatis connecting to the IPSec server. Refer to “Problem #7, I need to set up onlinegame hosting or use other Internet applications” for details. Check the Linksys website for more information at www.linksys.com.6. I need to set up a server behind my Router.To use a server like a web, ftp, or mail server, you need to know the respectiveport numbers they are using. For example, port 80 (HTTP) is used for web;port 21 (FTP) is used for FTP, and port 25 (SMTP outgoing) and port 110(POP3 incoming) are used for the mail server. You can get more informationby viewing the documentation provided with the server you installed. Followthese steps to set up port forwarding through the Router’s web-based utility. Wewill be setting up web, ftp, and mail servers.A. Access the Router’s web-based utility by going to http://192.168.1.1 or theIP address of the Router. Go to the Advanced => Port Forwarding tab. B. Enter any name you want to use for the Customized Application.C. Enter the External Port range of the service you are using. For example,if you have a web server, you would enter the range 80 to 80. D. Check the protocol you will be using, TCP and/or UDP. E. Enter the IP address of the PC or network device that you want the portserver to go to. For example, if the web server’s Ethernet adapter IP addressis 192.168.1.100, you would enter 100 in the field provided. Check“Appendix D: Finding the MAC Address and IP Address for Your EthernetAdapter” for details on getting an IP address.F. Check the Enable option for the port services you want to use. Consider theexample below:Customized External Port TCP UDP IP Address EnableApplicationWeb server 80 to 80 X X 192.168.1.100 XFTP server 21 to 21 X 192.168.1.101 XSMTP (outgoing) 25 to 25 X X 192.168.1.102 XPOP3 (incoming) 110 to 110 X X 192.168.1.102 XWhen you have completed the configuration, click the Apply button.71Instant Wireless®Series70D. Make sure you have the right cable. Check to see if the Internet column hasa solidly lit Link/Act LED. E. Make sure the cable connecting from your cable or DSL modem is con-nected to the Router’s Internet port. Verify that the Status page of theRouter’s web-based utility shows a valid IP address from your ISP.F. Turn off the computer, Router, and cable/DSL modem. Wait 30 seconds,and then turn on the Router, cable/DSL modem, and computer. Check theStatus tab of the Router’s web-based utility to see if you get an IP address. 4. I am not able to access the Setup page of the Router’s web-based utility.A. Refer to “Problem #2, I want to test my Internet connection” to verify thatyour computer is properly connected to the Router.B. Refer to “Appendix D: Finding the MAC Address and IP address for YourEthernet Adapter” to verify that your computer has an IP Address, SubnetMask, Gateway, and DNS.C. Set a static IP address on your system; refer to “Problem #1: I need to set astatic IP address.”D. Refer to “Problem #10: I need to remove the proxy settings or the dial-uppop-up window (for PPPoE users).”5. I can’t get my Virtual Private Network (VPN) working through the Router.Access the Router’s web interface by going to http://192.168.1.1 or the IPaddress of the Router, and go to the Advanced => Filters tab. Make sure youhave IPsec pass-through and/or PPTP pass-through enabled.VPNs that use IPSec with the ESP (Encapsulation Security Payload known asprotocol 50) authentication will work fine. At least one IPSec session will workthrough the Router; however, simultaneous IPSec sessions may be possible,depending on the specifics of your VPNs.VPNs that use IPSec and AH (Authentication Header known as protocol 51)are incompatible with the Router. AH has limitations due to occasional incom-patibility with the NAT standard. Change the IP address for the Router to another subnet to avoid a conflictbetween the VPN IP address and your local IP address. For example, if yourVPN server assigns an IP address 192.168.1.X (X is a number from 1 to 254)and your local LAN IP address is 192.168.1.X (X is the same number used inthe VPN IP address), the Router will have difficulties routing information tothe right location. If you change the Router’s IP address to 192.168.2.1, thatshould solve the problem. Change the Router’s IP address through the Setup tab
Dual-Band Wireless A+B Broadband Router 8. I can’t get the Internet game, server, or application to work.If you are having difficulties getting any Internet game, server, or applicationto function properly, consider exposing one PC to the Internet usingDeMilitarized Zone (DMZ) hosting. This option is available when an applica-tion requires too many ports or when you are not sure which port services touse. Make sure you disable all the forwarding entries if you want to success-fully use DMZ hosting, since forwarding has priority over DMZ hosting. (Inother words, data that enters the Router will be checked first by the forwardingsettings. If the port number that the data enters from does not have port for-warding, then the Router will send the data to whichever PC or network deviceyou set for DMZ hosting.) Follow these steps to set DMZ hosting:A. Access the Router’s web-based utility by going to http://192.168.1.1 or theIP address of the Router. Go to the Advanced => Port Forwarding tab.B. Disable or remove the entries you have entered for forwarding. Keep thisinformation in case you want to use it at a later time.C. Click the DMZ Host tab.D. Enter the Ethernet adapter’s IP address of the computer you want exposedto the Internet. This will bypass the NAT firewall for that computer. Pleaserefer to “Appendix D: Finding the MAC Address and IP Address for YourEthernet Adapter” for details on getting an IP address. Once completed with the configuration, click the Apply button.9. I forgot my password,or the password prompt always appears when I am sav-ing settings to the Router.Reset the Router to factory default by pressing the Reset button for 10 secondsand then releasing it. If you are still getting prompted for a password when sav-ing settings, then perform the following steps:A. Access the Router’s web-based utility by going to http://192.168.1.1 or theIP address of the Router. Enter the default password admin, and click thePassword tab. B. Enter a different password in the Router Password field, and enter thesame password in the second field to confirm the password.C. Click the Apply button.73Instant Wireless®Series7. I need to set up online game hosting or use other Internet applications.If you want to play online games or use Internet applications, most will workwithout doing any port forwarding or DMZ hosting. There may be cases whenyou want to host an online game or Internet application. This would require youto set up the Router to deliver incoming packets or data to a specific comput-er. This also applies to the Internet applications you are using. The best way toget the information on what port services to use is to go to the website of theonline game or application you want to use. Follow these steps to set up onlinegame hosting or use a certain Internet application:A. Access the Router’s web interface by going to http://192.168.1.1 or the IPaddress of the Router. Go to the Advanced => Port Forwarding tab.B. Enter any name you want to use for the Customized Application.C. Enter the External Port range of the service you are using. For example,if you want to host Unreal Tournament (UT), you would enter the range7777 to 27900.D. Check the protocol you will be using, TCP and/or UDP. E. Enter the IP address of the PC or network device that you want the portserver to go to. For example, if the web server’s Ethernet adapter IP addressis 192.168.1.100, you would enter 100 in the field provided. Check“Appendix D: Finding the MAC Address and IP Address for Your EthernetAdapter” for details on getting an IP address.F. Check the Enable option for the port services you want to use. Consider theexample below:Customized External Port TCP UDP IP Address EnableApplicationUT 7777 to 27900 X X 192.168.1.100 X Halflife 27015 to 27015 X X 192.168.1.105 XPC Anywhere 5631 to 5631 X 192.168.1.102 XVPN IPSEC 500 to 500 X 192.168.1.100 XWhen you have completed the configuration, click the Apply button.72
Dual-Band Wireless A+B Broadband Router 13. The firmware upgrade failed, and/or the Diag LED is flashing.The upgrade could have failed for a number of reasons. Follow these steps toupgrade the firmware and/or make the Diag LED stop flashing:A. If the firmware upgrade failed, use the TFTP program (it was downloadedalong with the firmware). Open the pdf that was downloaded along with thefirmware and TFTP program, and follow the pdf’s instructions.B. Set a static IP address on the PC; refer to “Problem #1, I need to set a stat-ic IP address.” Use the following IP address settings for the computer youare using:IP Address: 192.168.1.50Subnet Mask: 255.255.255.0Gateway: 192.168.1.1C. Perform the upgrade using the TFTP program or the Router’s web-basedutility through its Help tab.14. My DSL service’s PPPoE is always disconnecting.PPPoE is not actually a dedicated or always-on connection. The DSL ISP candisconnect the service after a period of inactivity, just like a normal phone dial-up connection to the Internet. There is a setup option to “keep alive” the con-nection. This may not always work, so you may need to re-establish connec-tion periodically.A. To connect to the Router, go to the web browser, and enterhttp://192.168.1.1 or the IP address of the Router.B. Enter the password, if asked. (The default password is admin.)C. On the Setup screen, select the option Keep Alive, and set the RedialPeriod option at 20 (seconds).D. Click the Apply button.E. Click the Status tab, and click the Connect button.F. You may see the login status display as Connecting. Press the F5 key torefresh the screen, until you see the login status display as Connected.G. Click the Apply button to continue.If the connection is lost again, follow steps E to G to re-establish connection.75Instant Wireless®Series10. I am a PPPoE user, and I need to remove the proxy settings or the dial-up pop-up window.If you have proxy settings, you need to disable these on your computer.Because the Router is the gateway for the Internet connection, the computerdoes not need any proxy settings to gain access. Please follow these directionsto verify that you do not have any proxy settings and that the browser you useis set to connect directly to the LAN.For Microsoft Internet Explorer 5.0 or higher:A. Click Start, Settings, and Control Panel. Double-click Internet Options. B. Click the Connections tab.C. Click the LAN settings button and remove anything that is checked.D. Click the OK button to go back to the previous screen.E. Click the option Never dial a connection. This will remove any dial-uppop-ups for PPPoE users.For Netscape 4.7 or higher:A. Start Netscape Navigator, and click Edit, Preferences, Advanced, andProxies. B. Make sure you have Direct connection to the Internet selected on thisscreen.C. Close all the windows to finish.11. To start over, I need to set the Router to factory default.Hold the Reset button for 10 seconds and then release it. This will return thepassword, forwarding, and other settings on the Router to the factory defaultsettings. In other words, the Router will revert to its original factory configu-ration.12. I need to upgrade the firmware.In order to upgrade the firmware with the latest features, you need to go to theLinksys website and download the latest firmware at www.linksys.com. Followthese steps:A. Go to the Linksys website at http://www.linksys.com and download thelatest firmware.B. To upgrade the firmware, follow the steps in the Help section found in“Chapter 6: The Router’s Web-based Utility.”74
Dual-Band Wireless A+B Broadband Router • Manually configure the TCP/IP settings with a DNS address provided byyour ISP.• Make sure that your browser is set to connect directly and that any dial-up is disabled. For Internet Explorer, click Tools, Internet Options, andthen the Connection tab. Make sure that Internet Explorer is set to Neverdial a connection. For Netscape Navigator, click Edit, Preferences,Advanced, and Proxy. Make sure that Netscape Navigator is set toDirect connection to the Internet.18. The Full/Col LED keeps flickering continuously.• Check the Category 5 Ethernet network cable and its RJ-45 connectors.• There may be interference with other network devices. Try removingother PCs or network devices to see if the problem persists. Eliminateeach network device one at a time to determine the cause.What is the maximum number of IP addresses that the Router will support? The Router will support up to 253 IP addresses.Is IPSec Pass-Through supported by the Router?Yes, it is a built-in feature that the Router automatically enables.Where is the Router installed on the network? In a typical environment, the Router is installed between the cable/DSL modemand the LAN. Plug the Router into the cable/DSL modem’s Ethernet port.Does the Router support IPX or AppleTalk? No. TCP/IP is the only protocol standard for the Internet and has become theglobal standard for communications. IPX, a NetWare communications protocolused only to route messages from one node to another, and AppleTalk, a com-munications protocol used on Apple and Macintosh networks, can be used forLAN to LAN connections, but those protocols cannot connect from the Internetto a LAN.Does the Internet connection of the Router support 100Mbps Ethernet? The Router’s current hardware design supports up to 100Mbps Ethernet on itsInternet port; however, the Internet connection speed will vary depending onthe speed of your broadband connection. The Router also supports 100Mbpsover the auto-sensing Fast Ethernet 10/100 switch on the LAN side of theRouter. 77Instant Wireless®Series15. I can’t access my e-mail, web, or VPN, or I am getting corrupted data from theInternet.The Maximum Transmission Unit (MTU) setting may need to be adjusted. Bydefault, the MTU is set at 1500. For most DSL users, it is strongly recom-mended to use MTU 1492. If you are having some difficulties, perform the fol-lowing steps:A. To connect to the Router, go to the web browser, and enterhttp://192.168.1.1 or the IP address of the Router.B. Enter the password, if asked. (The default password is admin.)C. Click the Advanced => Filters tab.D. Look for the MTU option, and select Enable. In the Size field, enter 1492. E. Click the Apply button to continue.If your difficulties continue, change the Size to different values. Try this list ofvalues, one value at a time, in this order, until your problem is solved:146214001362130016. The Diag LED stays lit continuously.• The Diag LED lights up when the device is first powered up. Meantime,the system will boot up itself and check for proper operation. After fin-ishing the checking procedure, the LED turns off to show that the systemis working fine. If the LED remains lit after this time, the device is notworking properly. Try to flash the firmware by assigning a static IPaddress to the computer, and then upgrade the firmware. Try using thefollowing settings, IP Address: 192.168.1.50 and Subnet Mask:255.255.255.0.17. When I enter a URL or IP address,I get a time-out error or am prompted to retry.• Check if other PCs work. If they do, ensure that your workstation’s IP set-tings are correct (IP Address, Subnet Mask, Default Gateway, and DNS).Restart the computer that is having a problem.• If the PCs are configured correctly, but still not working, check theRouter. Ensure that it is connected and powered on. Connect to it andcheck its settings. (If you cannot connect to it, check the LAN and powerconnections.)• If the Router is configured correctly, check your Internet connection(DSL/cable modem, etc.) to see if it is working correctly. You can removethe Router to verify a direct connection.76Frequently Asked Questions
Dual-Band Wireless A+B Broadband Router 79Instant Wireless®Series78same CD key connect at the same time, even if on the same LAN (not a prob-lem with 1.0.1.3). As far as hosting games, the HL server does not need to bein the DMZ. Just forward port 27015 to the local IP address of the server com-puter. How can I block corrupted FTP downloads? If you are experiencing corrupted files when you download a file with your FTPclient, try using another FTP program.The web page hangs; downloads are corrupt, or nothing but junk characters arebeing displayed on the screen. What do I need to do?Force your Ethernet adapter to 10Mbps or half duplex mode, and turn off the“Auto-negotiate” feature of your Ethernet adapter as a temporary measure.(Please look at the Network Control Panel in your Ethernet adapter’s AdvancedProperties tab.) Make sure that your proxy setting is disabled in the browser.Check our website at www.linksys.com for more information.If all else fails in the installation, what can I do?Reset the Router by holding down the reset button until the Diag LED fullyturns on and off. Reset your cable or DSL modem by powering the unit off andthen on. Obtain and flash the latest firmware release that is readily availableon the Linksys website, www.linksys.com.How will I be notified of new Router firmware upgrades?All Linksys firmware upgrades are posted on the Linksys website atwww.linksys.com, where they can be downloaded for free. To upgrade theRouter’s firmware, use the Help tab of the Router’s web-based utility. If theRouter’s Internet connection is working well, there is no need to download anewer firmware version, unless that version contains new features that youwould like to use. Downloading a more current version of Router firmwarewill not enhance the quality or speed of your Internet connection, and may dis-rupt your current connection stability.Will the Router function in a Macintosh environment? Yes, but the Router’s setup pages are accessible only through Internet Explorer4.0 or Netscape Navigator 4.0 or higher for Macintosh.I am not able to get the web configuration screen for the Router. What can I do?You may have to remove the proxy settings on your Internet browser, e.g.,Netscape Navigator or Internet Explorer. Or remove the dial-up settings onyour browser. Check with your browser documentation, and make sure thatWhat is Network Address Translation and what is it used for?Network Address Translation (NAT) translates multiple IP addresses on the pri-vate LAN to one public address that is sent out to the Internet. This adds a levelof security since the address of a PC connected to the private LAN is nevertransmitted on the Internet. Furthermore, NAT allows the Router to be usedwith low cost Internet accounts, such as DSL or cable modems, when only oneTCP/IP address is provided by the ISP. The user may have many privateaddresses behind this single address provided by the ISP.Does the Router support any operating system other than Windows 95, Windows98,Windows Millennium,Windows 2000,Windows NT, or Windows XP? Yes, but Linksys does not, at this time, provide technical support for setup, con-figuration or troubleshooting of any non-Windows operating systems.Does the Router support ICQ send file?Yes, with the following fix: click ICQ menu -> preference -> connectionstab->, and check I am behind a firewall or proxy. Then set the firewall time-out to 80 seconds in the firewall setting. The Internet user can then send a fileto a user behind the Router.I set up an Unreal Tournament Server, but others on the LAN cannot join. What doI need to do? If you have a dedicated Unreal Tournament server running, you need to createa static IP for each of the LAN computers and forward ports 7777, 7778, 7779,7780, 7781, and 27900 to the IP address of the server. You can also use a portforwarding range of 7777 ~ 27900. If you want to use the UT Server Admin,forward another port. (Port 8080 usually works well but is used for remoteadmin. You may have to disable this.) Then in the [UWeb.WebServer] sectionof the server.ini file, set the ListenPort to 8080 (to match the mapped portabove) and ServerName to the IP assigned to the Router from your ISP.Can multiple gamers on the LAN get on one game server and play simultaneouslywith just one public IP address?It depends on which network game or what kind of game server you are using.For example, Unreal Tournament supports multi-login with one public IP.How do I get Half-Life:Team Fortressto work with the Router?The default client port for Half-Life is 27005. The computers on your LANneed to have “+clientport 2700x” added to the HL shortcut command line; thex would be 6, 7, 8, and on up. This lets multiple computers connect to the sameserver. One problem: Version 1.0.1.6 won’t let multiple computers with the
Dual-Band Wireless A+B Broadband Router 81Instant Wireless®Series80will work through the Router; however, simultaneous IPSec sessions may bepossible, depending on the specifics of your VPNs. How can I check whether I have static or DHCP IP Addresses?Consult your ISP to obtain this information. How do I get mIRC to work with the Router?Under the Port Forwarding tab, set port forwarding to 113 for the PC on whichyou are using mIRC.Can the Router act as my DHCP server?Yes. The Router has DHCP server software built-in.Can I run an application from a remote computer over the wireless network?This will depend on whether or not the application is designed to be used overa network. Consult the application’s documentation to determine if it supportsoperation over a network.What is the IEEE 802.11a standard?It is one of the IEEE standards for wireless networks. The 802.11a standardallows wireless networking hardware from different manufacturers to commu-nicate, provided that the hardware complies with the 802.11a standard. The802.11a standard states a maximum data transfer rate of 54Mbps and an oper-ating frequency of 5GHz.What is the IEEE 802.11b standard?It is one of the IEEE standards for wireless networks. The 802.11b standardallows wireless networking hardware from different manufacturers to commu-nicate, provided that the hardware complies with the 802.11b standard. The802.11b standard states a maximum data transfer rate of 11Mbps and an oper-ating frequency of 2.4GHz.What IEEE 802.11a features are supported?The product supports the following IEEE 802.11a functions: • OFDM protocol • Multi-Channel Roaming • Automatic Rate Selection • RTS/CTS feature • Fragmentation your browser is set to connect directly and that any dial-up is disabled. Makesure that your browser is set to connect directly and that any dial-up is disabled.For Internet Explorer, click Tools, Internet Options, and then the Connectiontab. Make sure that Internet Explorer is set to Never dial a connection. ForNetscape Navigator, click Edit, Preferences, Advanced, and Proxy. Makesure that Netscape Navigator is set to Direct connection to the Internet.What is DMZ Hosting?Demilitarized Zone (DMZ) allows one IP address (computer) to be exposed tothe Internet. Some applications require multiple TCP/IP ports to be open. It isrecommended that you set your computer with a static IP if you want to useDMZ Hosting. To get the LAN IP address, see “Appendix D: Finding the MACAddress and IP Address for Your Ethernet Adapter.”If DMZ Hosting is used,does the exposed user share the public IP with the Router?No.Does the Router pass PPTP packets or actively route PPTP sessions? The Router allows PPTP packets to pass through.Is the Router cross-platform compatible? Any platform that supports Ethernet and TCP/IP is compatible with the Router.How many ports can be simultaneously forwarded? Theoretically, the Router can establish 520 sessions at the same time, but youcan only forward 10 ranges of ports.Does the Router replace a modem? Is there a cable or DSL modem in the Router?No, the Router must work in conjunction with a cable or DSL modem.Which modems are compatible with the Router? The Router is compatible with virtually any cable or DSL modem that supportsEthernet.What are the advanced features of the Router?The Router’s advanced features include Advanced Wireless settings, Filtering,Port Forwarding, Routing, DMZ Hosting, and MAC Address Cloning.What is the maximum number of VPN sessions allowed by the Router?The maximum number depends on many factors. At least one IPSec session
Dual-Band Wireless A+B Broadband Router from its original access point, it undertakes a new search. Upon finding a newaccess point, it then re-registers, and the communication process continues.What is ISM band?The FCC and their counterparts outside of the U.S. have set aside bandwidthfor unlicensed use in the ISM (Industrial, Scientific and Medical) band.Spectrum in the vicinity of 2.4 GHz, in particular, is being made availableworldwide. This presents a truly revolutionary opportunity to place convenienthigh-speed wireless capabilities in the hands of users around the globe. What is Spread Spectrum?Spread Spectrum technology is a wideband radio frequency technique devel-oped by the military for use in reliable, secure, mission-critical communica-tions systems. It is designed to trade off bandwidth efficiency for reliability,integrity, and security. In other words, more bandwidth is consumed than in thecase of narrowband transmission, but the trade-off produces a signal that is, ineffect, louder and thus easier to detect, provided that the receiver knows theparameters of the spread-spectrum signal being broadcast. If a receiver is nottuned to the right frequency, a spread-spectrum signal looks like backgroundnoise. There are two main alternatives, Direct Sequence Spread Spectrum(DSSS) and Frequency Hopping Spread Spectrum (FHSS).What is DSSS? What is FHSS? And what are their differences?Frequency-Hopping Spread-Spectrum (FHSS) uses a narrowband carrier thatchanges frequency in a pattern that is known to both transmitter and receiver.Properly synchronized, the net effect is to maintain a single logical channel. Toan unintended receiver, FHSS appears to be short-duration impulse noise.Direct-Sequence Spread-Spectrum (DSSS) generates a redundant bit patternfor each bit to be transmitted. This bit pattern is called a chip (or chippingcode). The longer the chip, the greater the probability that the original data canbe recovered. Even if one or more bits in the chip are damaged during trans-mission, statistical techniques embedded in the radio can recover the originaldata without the need for retransmission. To an unintended receiver, DSSSappears as low power wideband noise and is rejected (ignored) by most nar-rowband receivers. Will the information be intercepted while it is being transmitted through the air?WLAN features two-fold protection in security. On the hardware side, as withDirect Sequence Spread Spectrum technology, it has the inherent security fea-ture of scrambling. On the software side, WLAN offers the encryption function(WEP) to enhance security and access control.83Instant Wireless®SeriesWhat IEEE 802.11b features are supported?The product supports the following IEEE 802.11b functions: • CSMA/CA plus Acknowledge protocol • Multi-Channel Roaming • Automatic Rate Selection • RTS/CTS feature • Fragmentation • Power Management What is ad-hoc mode?When a wireless network is set to ad-hoc mode, the wireless-equipped com-puters are configured to communicate directly with each other. The ad-hocwireless network will not communicate with any wired network. What is infrastructure mode?When a wireless network is set to infrastructure mode, the wireless network isconfigured to communicate with a wired network through a wireless accesspoint.What is roaming?Roaming is the ability of a portable computer user to communicate continu-ously while moving freely throughout an area greater than that covered by a sin-gle access point. Before using the roaming function, the workstation must makesure that it is the same channel number with the access point of dedicated cov-erage area. To achieve true seamless connectivity, the wireless LAN must incorporate anumber of different functions. Each node and access point, for example, mustalways acknowledge receipt of each message. Each node must maintain contactwith the wireless network even when not actually transmitting data. Achievingthese functions simultaneously requires a dynamic RF networking technologythat links access points and nodes. In such a system, the user’s end node under-takes a search for the best possible access to the system. First, it evaluates suchfactors as signal strength and quality, as well as the message load currentlybeing carried by each access point and the distance of each access point to thewired backbone. Based on that information, the node next selects the rightaccess point and registers its address. Communications between end node andhost computer can then be transmitted up and down the backbone.As the user moves on, the end node’s RF transmitter regularly checks the sys-tem to determine whether it is in touch with the original access point or whetherit should seek a new one. When a node no longer receives acknowledgment 82
Dual-Band Wireless A+B Broadband Router I have excellent signal strength,but I cannot see my network. WEP is probably enabled on the Router, but not on your wireless adapter (orvice versa). Verify that the same WEP keys and levels (64, 128, or 152) arebeing used on all nodes of your wireless network. How many channels/frequencies are available with the Router?Using 802.11a, there are eight available channels, ranging from 36 to 64.Using 802.11b, there are eleven available channels, ranging from 1 to 11. What is Turbo Mode?Turbo Mode allows high-speed connections, but severely limits range. Towork, Turbo Mode must be enabled on both the Router and the wireless PCs.Turbo Mode is not compatible with Windows XP and may only function withLinksys 5GHz wireless adapters.What is the difference in range between 802.11a and 802.11b products?Overall, range will be a little less in a typical environment, and while higherspeeds may be achieved with 802.11a, throughput degrades more quickly. (SeeFigure A-1.)If your questions are not addressed here, refer to the Linksys website,www.linksys.com.85Instant Wireless®Series84What is WEP?WEP is Wired Equivalent Privacy, a data privacy mechanism based on a 64-bitor 128-bit shared key algorithm, as described in the IEEE 802.11 standard.What is a MAC Address?The Media Access Control (MAC) address is a unique number assigned by themanufacturer to any Ethernet networking device, such as a network adapter,that allows the network to identify it at the hardware level. For all practical pur-poses, this number is usually permanent. Unlike IP addresses, which canchange every time a computer logs onto the network, the MAC address of adevice stays the same, making it a valuable identifier for the network.How do I avoid interference?If you are using the Router and one or more Access Points in close proximityto one another, and they are set on the same channel, interference will be gen-erated. To avoid interference, be sure to set the Router and all Access Points todifferent channels (frequencies); in other words, assign a unique channel to theRouter and each Access Point.How do I reset the Router?Press the Reset button on the back panel for about ten seconds. This will resetthe Router to its default settings.How do I resolve issues with signal loss?There is no way to know the exact range of your wireless network without test-ing. Every obstacle placed between the Router and a wireless PC will createsignal loss. Lead glass, metal, concrete floors, water and walls will inhibit thesignal and reduce range. Start with the Router and your wireless PC in thesame room and move it away in small increments to determine the maximumrange in your environment. You may also try using different channels, as this may eliminate interferenceaffecting only one channel. Also, due to FCC regulations, more power may betransmitted, using 802.11a, on channels 52, 56, 60 and 64, than on the lowerchannels. Lastly, click the Advanced tab of the web-based utility and makesure that FULL is selected in the Transmission Power field.Does the Turbo Mode work with Windows XP PCs?No. The Turbo Mode does not work with Windows XP PCs.Figure A-1
Dual-Band Wireless A+B Broadband Router 87Instant Wireless®Series86Step One: Pinging an IP AddressThe first step to determining your ISP’s web and e-mail server address is toping its IP address.1. Power on the computer and the cable or DSL modem, and restore the net-work configuration set by your ISP if you have since changed it.2. Click Start and then Run. Type command in the Open field. This willbring up the DOS window.3. At the DOS command prompt, type ping mail (assuming that the locationfor which you’re trying to find an IP address is configured as mail). Pressthe Enter key. Information such as the following data, taken from a ping ofMicrosoft Network’s e-mail server, will be displayed.C:\>ping mailPinging mail [24.53.32.4] with 32 bytes of data:Reply from 24.53.32.4: bytes=32 time<10ms TTL=128Reply from 24.53.32.4: bytes=32 time<10ms TTL=128Reply from 24.53.32.4: bytes=32 time<10ms TTL=128Reply from 24.53.32.4: bytes=32 time<10ms TTL=128Ping statistics for 24.53.32.4:Packets: Sent = 4, Received = 4, Lost = 0 (0%loss),Approximate round trip times in milli-seconds:Minimum = 0ms, Maximum = 0ms, Average = 0ms4. Write down the IP address returned by the ping command (in the exampleabove: 24.53.32.4.). This IP address is the actual IP address of the servermail, or any other word or value you have pinged.Figure B-1Appendix B:How to Ping YourISP’s E-mail &Web AddressesVirtually all Internet addresses are configured with words or characters (e.g.,www.linksys.com, www.yahoo.com, etc.) In actuality, however, these Internetaddresses are assigned to IP addresses, which are the true addresses on theInternet. For example, www.yahoo.com is 66.218.71.87 (this IP address maychange). Type it into your web browser and you will wind up at the Linksyshome page every time. There are servers that translate the URL to an IPaddress; this is called the Domain Name System (DNS).IP and web addresses, however, can sometimes be long and hard to remember.Because of this, certain ISPs will shorten their server addresses to single wordsor codes on their users’ web browser or e-mail configurations. If your ISP’s e-mail and web server addresses are configured with single words (www, e-mail,home, pop3, etc.) rather than whole Internet addresses or IP addresses, theRouter may have problems sending or receiving mail and accessing theInternet. This happens because the Router has not been configured by your ISPto accept their abbreviated server addresses.The solution is to determine the true web addresses behind your ISPs codewords. You can determine the IP and web addresses of your ISP’s servers by“pinging” them.Important: If you don’t have your ISP’s web and e-mail IPaddresses, you must either get them from your ISP or follow thesesteps prior to connecting the Router to your network.
Dual-Band Wireless A+B Broadband Router 89Instant Wireless®Series88Appendix C:ConfiguringWireless SecurityThe Router offers two wireless security features. The basic feature is WiredEquivalent Privacy (WEP) encryption, an encryption method used to protectyour wireless data communications. WEP uses 64-bit, 128-bit, or 152-bit keysto provide access control to your network and encryption security for everydata transmission. To decode a data transmission, each point in a network mustuse an identical key. Higher encryption levels mean higher levels of security,but due to the complexity of the encryption, they may mean decreased networkperformance.You may also have heard the term “40-bit” used in conjunction with WEPencryption. This is simply another term for 64-bit WEP encryption. This levelof WEP encryption has been called 40-bit because it uses a 40-bit secret keyalong with a 24-bit Initialization Vector (40 + 24 = 64). Wireless vendors mayuse either name. Linksys uses the term “64-bit” when referring to this level ofencryption.The second wireless security feature is 802.1x. The IEEE 802.1x standard spec-ifies authentication methods for a wireless client, such as a PC, to access a net-work, so network security is enhanced. Based on the Extensible AuthenticationProtocol (EAP), 802.1x designates how a client accesses a network server, fre-quently a RADIUS server, with the Router acting as an authenticator. When anetwork uses 802.1x, the identity of the client is verified before the client isallowed network access. For example, a wireless user may use one of the authentication methods toaccess a wireless network protected by an authentication server. The user’s PCsends a request to the Router (an access point can be used instead). The Routersends an identification request back to the PC. After the PC sends the Router theidentification message, the Router forwards the identification message to theserver. If the server accepts the identification message, then the PC is permittedaccess to the wireless network.BackgroundNote: WEP encryption is an additional data security measure and notessential for router operation; however, Linksys recommends the useof WEP encryption. Step Two: Pinging for a Web AddressWhile the IP address returned above would work as your e-mail server address,it may not be permanent. IP addresses change all the time. Web addresses, how-ever, usually don’t. Because of this, you’re likely to have fewer problems byconfiguring your system with web addresses rather than IP addresses. Followthe instructions below to find the web address assigned to the IP address youjust pinged.1. At the DOS command prompt, type ping -a 24.53.32.4, where 24.53.32.4is the IP address you just pinged. Information such as the following datawill be displayed.C:\>ping -a 24.53.32.4Pinging mail.msnv3.occa.home.com [24.53.32.4] with32 bytes of data:Reply from 24.53.32.4: bytes=32 time<10ms TTL=127Reply from 24.53.32.4: bytes=32 time<10ms TTL=127Reply from 24.53.32.4: bytes=32 time<10ms TTL=127Reply from 24.53.32.4: bytes=32 time<10ms TTL=127Ping statistics for 24.53.32.4:Packets: Sent = 4, Received = 4, Lost = 0 (0%loss),Approximate round trip times in milli-seconds:Minimum = 0ms, Maximum = 0ms, Average = 0ms2. Write down the web address returned by the ping command. (In the exam-ple in Figure C-2, mail.msnv3.occa.home.com is the web address.) Thisweb address is the web address assigned to the IP address you just pinged.While the IP address of mail could conceivably change, it is likely that thisweb address will not.3. Replace your ISP’s abbreviated server address with this extended webaddress in the corresponding Internet application (web browser, e-mailapplication, etc.).Once you have replaced the brief server address with the true server address,the Router should have no problem accessing the Internet through that Internetapplication.Figure B-2
Dual-Band Wireless A+B Broadband Router In addition to enabling WEP, Linksys also recommends the following securityimplementations:•Change the SSID from the default “linksys”•Change the SSID on a regular basis•Change the WEP key regularly•Enable MAC address filtering (if your wireless products allow it)For instructions on how to configure the Router’s WEP settings, go to the“Setup” section of “Chapter 6: The Router’s Web-Based Utility.” For instruc-tions on how to configure the WEP settings of your PC’s wireless adapter, referto your wireless adapter’s documentation.Many authentication methods, including passwords, certificates, and smartcards (plastic cards that hold data), work within the 802.1x framework. TheRouter supports two authentication types: MD5 and certificate-based (TLS orTTLS).MD5 authentication is a type of one-way authentication method that employsuser names and passwords. TLS and TTLS authentication are two-way authen-tication methods that employ digital certificates to verify the identity of aclient. TLS, or EAP-TLS, exclusively uses digital certificates, while TTLS, orEAP-TTLS, uses a combination of certificates and another method, such aspasswords, for authentication. MD5 authentication is not as secure as eithercertificate-based authentication method, and TLS is more secure than TTLSauthentication. To use 802.1x authentication, you have to enable the 802.1x feature on theRouter as well as your wireless-equipped PCs. For instructions on how to con-figure the Router’s 802.1x settings, go to the “Advanced Wireless” section of“Chapter 6: The Router’s Web-Based Utility.” 91Instant Wireless®Series90Important: The Router’s 802.1x feature works with Windows XP.It may also work with other Windows operating systems, depend-ing on the specifics of your PC’s operating system and the 802.1xclient software being used.802.1x AuthenticationImportant: The Router’s 802.1x feature works with a RADIUSserver. It may also work with other types of authentication servers,depending on the specifics of each authentication server. There are two types of WEP encryption for 802.1x, static and dynamic. StaticWEP keys are more vulnerable and can only be changed manually on alldevices, including the Router. If you are using MD5 authentication, then youcan only use static WEP keys. Dynamic WEP keys are keys that are renewedautomatically on a periodic basis. This makes the WEP key(s) more difficult tobreak, so network security is strengthened. To enable dynamic WEP keys, youmust use 802.1x certificate-based authentication methods, such as TLS orTTLS.Make sure your wireless network is functioning before attempting to configureWEP encryption.On a wireless network, a 128-bit WEP encrypted device will NOT communi-cate with a 64-bit WEP encrypted device. Therefore, make sure that all of thewireless devices on each network are using the same encryption level. Note: 802.1x is an advanced data security measure and not essentialfor router operation. It will, however, increase network security. Note: If you are roaming between access points, you will have to gothrough the 802.1x authentication procedure each time your computerconnects to a new access point.Figure C-1Cable or DSL Modem RouterRADIUS ServerNotebook withWireless AdapterNotebook withWireless AdapterWEP Encryption
Dual-Band Wireless A+B Broadband Router 93Instant Wireless®Series922. The screen that appears will show any available wireless network. Select theappropriate network, and click the Advanced... button.3. Click the Authentication tab. Make sure the box next to Enable networkaccess control using IEEE 802.1X is checked. In the drop-down box nextto EAP type, select MD5-Challenge. Make sure the box next toAuthenticate as computer when computer information is available ischecked. Then click the OK button.Figure C-4Figure C-3Windows XP supports 802.1x with MD5 or TLS authentication. In this appen-dix, the following sections will discuss 802.1x configuration for PCs runningWindows XP. If you are using MD5 authentication, proceed to “MD5Authentication for Windows XP.” If you are using TLS authentication, go to theappropriate section, “Digital Certificate Installation” or “TLS Authenticationfor Windows XP,” depending on whether or not you have already installed adigital certificate on your PC.If your PC is not running Windows XP, then your PC must use third-party802.1x client software. For instructions on how to configure 802.1x throughthird-party software, refer to that application’s documentation. 1. Make sure you have installed the wireless adapter correctly into your PC.Click the Wireless Network Connection icon located in your computer’ssystem tray. MD5 Authentication for Windows XPImportant: Make sure you have the User name, Password, Logondomain (if applicable), and WEP key needed to access the appropriatewireless network. If you need any of this information, contact your net-work administrator beforehand. Figure C-2Note: These are the instructions and screenshots for Windows XPwithout Service Pack 1 installed. If you have already installedService Pack 1, enter the keyword 802.1x in the Windows XP searchengine for your 802.1x setup instructions.
Dual-Band Wireless A+B Broadband Router 95Instant Wireless®Series946. Enter the WEP key in the Network key field. Then click the OK button.7. Make sure the network you want is selected in the Preferred networks box,and then click the OK button.Figure C-8Figure C-74. Click the Wireless Networks tab. Select the wireless network you want toconnect to, and click the Configure button. If you don’t see the wirelessnetwork you want, then click the Refresh button.5. Make sure the box next to Data encryption (WEP enabled) is checked.Uncheck the box next to The key is provided for me automatically. Figure C-6Figure C-5
Dual-Band Wireless A+B Broadband Router 97Instant Wireless®Series8. Click the Wireless Network Connection icon located in your computer’ssystem tray. 9. Complete the User name and Password fields. Complete the Logon domainfield if necessary. Then click the OK button.10. Open your PC’s web browser and test your Internet connection. If you areunable to connect to the Internet, double-check the settings you configuredthrough Windows XP and the Router’s web-based utility.For more details about wireless networking or 802.1x on a Windows XP com-puter, enter the keyword wireless or 802.1x in the Windows XP search engine.96Before accessing the wireless network, you must have a digital certificateinstalled on your PC. Proceed to step 1 for instructions on how to request a dig-ital certificate from a Windows 2000 RADIUS server through the Internet. Ifyou need to request a digital certificate using a different method, contact yournetwork administrator. If you already have a certificate installed, proceed to the“TLS Authentication for Windows XP” section.1. Open your PC’s web browser. In the Address field, enter http:\\IP addressof the RADIUS server\certsrv. For example, if the IP address of theRADIUS server is 10.10.10.2, then enter http:\\10.10.10.2\certsrv. 2. Complete the User name and Password fields. Then click the OK button.Digital Certificate InstallationImportant: Before you install the digital certificate, make sure youhave the IP address, User name, and Password for the RADIUS serverof the wireless network. If you need any of this information, contactyour network administrator beforehand. Important: To request a digital certificate from a Windows 2000RADIUS server, you must use an active Internet connection. Figure C-11Figure C-12Figure C-10Figure C-9
Dual-Band Wireless A+B Broadband Router 99Instant Wireless®Series985. Click the Submit button.6. Click Install this certificate.7. You will be asked if you want to add the certificate to the Root Store. Clickthe Yes button.Figure C-15Figure C-16Figure C-173. Click the radio button next to Request a certificate, and then click theNext button.4. Click the radio button next to User certificate request:, and make sureUser Certificate is selected. Then click the Next button.Figure C-13Figure C-14
Dual-Band Wireless A+B Broadband Router 1. Make sure you haveinstalled the wirelessadapter correctly into yourPC. Click the WirelessNetwork Connection iconlocated in your computer’ssystem tray. 2. The screen that appears will show any available wireless network. Select theappropriate network, and click the Advanced... button.101Instant Wireless®Series8. You will be informed when the certificate has been successfully installed.Then close your PC’s web browser.Proceed to the next section, “TLS Authentication for Windows XP.”100Figure C-20Figure C-19Note: These are the instructions and screenshots for Windows XPwithout Service Pack 1 installed. If you have already installedService Pack 1, enter the keyword 802.1x in the Windows XP searchengine for your 802.1x setup instructions.TLS Authentication for Windows XPImportant: Make sure you have a digital certificated installed on yourPC. If you need to request a digital certificate, go to the previous sec-tion, “Digital Certificate Installation.”Figure C-18
Dual-Band Wireless A+B Broadband Router 5. Make sure the box next to Data encryption (WEP enabled) is checked.Make sure the box next to The key is provided for me automatically ischecked. Then click the OK button.6. Make sure the appropriate network is selected, and click the OK button.103Instant Wireless®Series3. Click the Authentication tab. Make sure the box next to Enable networkaccess control using IEEE 802.1X is checked. In the drop-down box nextto EAP type, select Smart Card or other Certificate. Make sure the boxnext to Authenticate as computer when computer information is avail-able is checked. Then click the OK button.4. Click the Wireless Networks tab. Select the wireless network you want toconnect to, and click the Configure button.102Figure C-23Figure C-24Figure C-21Figure C-22
Dual-Band Wireless A+B Broadband Router Appendix D:Finding the MACAddress and IPAddress for YourEthernet AdapterThis section describes how to find the MAC address for your Ethernet adapterto do either MAC address filtering or MAC address cloning for the Router andISP. You can also find the IP address of your computer’s Ethernet adapter. TheIP address is used for filtering, forwarding, and DMZ. Follow the steps in thisappendix to find the MAC address or IP address for your adapter in Windows95, 98, Me, NT, 2000, and XP. For Windows 95, 98, and Me:1. Click on Start and Run. In the Open field, enter winipcfg. Then press theEnter key or the OK button.2. When the IP Configuration window appears, select the Ethernet adapteryou are using to connect to the Router via a Category 5 Ethernet networkcable.105Instant Wireless®Series7. Click the Wireless Network Connection icon located in your computer’ssystem tray. 8. If this is the first time you are using this 802.1x connection, you will beasked if you want to accept the wireless network connection. Click the OKbutton.9. Open your PC’s web browser and test your Internet connection. If you areunable to connect to the Internet, double-check the settings you configuredthrough Windows XP and the Router’s web-based utility.For more details about wireless networking or 802.1x on a Windows XP com-puter, enter the keyword wireless or 802.1x in the Windows XP search engine.104Figure D-1Figure D-2Figure C-25Figure C-26
Dual-Band Wireless A+B Broadband Router 2. In the command prompt, enter ipconfig /all. Then press the Enter key.3. Write down the Physical Address as shown on your computer screen; it isthe MAC address for your Ethernet adapter. This will appear as a series ofletters and numbers. The MAC address/Physical Address is what you will use for MAC addresscloning or MAC filtering. Write down the IP Address as shown on your computer screen. The exam-ple in Figure E-5 shows the IP address of your Ethernet adapter as192.168.1.100. Your computer may show something different. 107Instant Wireless®Series3. Write down the Adapter Address as shown on your computer screen (seeFigure E-3). This is the MAC address for your Ethernet adapter and willbe shown as a series of numbers and letters. The MAC address/Adapter Address is what you will use for MAC addresscloning or MAC filtering. Write down the IP Address as shown on your computer screen. The exam-ple in Figure E-3 shows the IP address of your Ethernet adapter as192.168.1.100. Your computer may show something different. For Windows NT, 2000, and XP:1. Click Start and Run. In the Open field, enter cmd. Press the Enter key orclick the OK button.106Figure D-5Note: The MAC address is also called the PhysicalAddress.Figure D-3Figure D-4Note: The MAC address is also called the AdapterAddress.
Dual-Band Wireless A+B Broadband Router (NIC) is the typical adapter that allows the PC or server to connect to theintranet and/or Internet.Ad-hoc Network - An ad-hoc network is a group of computers, each with awireless adapter, connected as an independent 802.11 wireless LAN. Ad-hocwireless computers operate on a peer-to-peer basis, communicating directlywith each other without the use of an access point. Ad-hoc mode is alsoreferred to as an Independent Basic Service Set (IBSS) or as peer-to-peermode, and is useful at a departmental scale or SOHO operation.Automatic Fall-back - A feature provided by some wireless products toincrease connection reliability. Automatic fall-back enables a device to dynam-ically shift between various data transfer rates. It works by decreasing the datatransfer rate when interference increases, distance increases, and other factorsundermine signal strength and quality.Auto-MDI/MDIX - On a network hub or switch, an auto-MDI/MDIX portautomatically senses if it needs to act as a MDI or MDIX port. The auto-MDI/MDIX capability eliminates the need for crossover cables.Auto-negotiate - To automatically determine the correct settings. The term isoften used with communications and networking. For example, Ethernet10/100 cards, hubs, and switches can determine the highest speed of the nodethey are connected to and adjust their transmission rate accordingly.Backbone – The part of a network that connects most of the systems and net-works together and handles the most data.Bandwidth - The transmission capacity of a given facility, in terms of howmuch data the facility can transmit in a fixed amount of time; expressed in bitsper second (bps).Beacon Interval - A beacon is a packet broadcast by the Access Point to keepthe network synchronized. A beacon includes the wireless LAN service area,the AP address, the Broadcast destination addresses, a time stamp, DeliveryTraffic Indicator Maps, and the Traffic Indicator Message (TIM).Bit – A binary digit. The value—0 or 1—used in the binary numbering system.Also, the smallest form of data.Boot – To cause the computer to start executing instructions. Personal comput-ers contain built-in instructions in a ROM chip that are automatically executed109Instant Wireless®Series108Appendix E: Glossary10BaseT - An Ethernet standard that uses twisted wire pairs.100BaseTX - IEEE physical layer specification for 100 Mbps over two pairs ofCategory 5 UTP or STP wire.802.11a - One of the IEEE standards for wireless networking hardware.Products that adhere to a specific IEEE standard will work with each other,even if they are manufactured by different companies. It specifies a maximumdata transfer rate of 54Mbps and an operating frequency of 5GHz. The 802.11astandard uses the Orthogonal Frequency Division Multiplexing (OFDM) trans-mission method. Additionally, the 802.11a standard supports 802.11 featuressuch as WEP encryption for security.802.11b - One of the IEEE standards for wireless networking hardware.Products that adhere to a specific IEEE standard will work with each other,even if they are manufactured by different companies. The 802.11b standardspecifies a maximum data transfer rate of 11Mbps, an operating frequency of2.4GHz, and WEP encryption for security. 802.11b networks are also referredto as Wi-Fi networks.802.1x - Based on the Extensible Authentication Protocol (EAP), the 802.1xstandard is one of the IEEE standards for network authentication and key man-agement. It establishes a framework that supports multiple authentication meth-ods. This standard can be incorporated into any type of network to enhance itssecurity. For example, a wireless user may use one of the authentication methods toaccess a wireless network protected by an authentication server. The user, alsocalled the supplicant, sends a request to an access point or wireless router, alsocalled the authenticator. The authenticator sends an identification request backto the user. After the user sends the authenticator the identification message, theauthenticator forwards the user’s identification message to the authenticationserver. If the server accepts the identification message, then the user is permit-ted access to the wireless network. The 802.1x standard can also support encryp-tion key management to strengthen wireless network encryption services.Adapter - Printed circuit board that plugs into a PC to add to capabilities orconnectivity to a PC. In a networked environment, a network interface card
Dual-Band Wireless A+B Broadband Router CSMA/CD (Carrier Sense Multiple Access/Collision Detection) - The LANaccess method used in Ethernet. When a device wants to gain access to the net-work, it checks to see if the network is quiet (senses the carrier). If it is not, itwaits a random amount of time before retrying. If the network is quiet and twodevices access the line at exactly the same time, their signals collide. When thecollision is detected, they both back off and each waits a random amount oftime before retrying. CTS (Clear To Send) - An RS-232 signal sent from the receiving station to thetransmitting station that indicates it is ready to accept data.Database - A database is a collection of data that is organized so that its con-tents can easily be accessed, managed, and updated. Data Packet - One frame in a packet-switched message. Most data communi-cations is based on dividing the transmitted message into packets. For example,an Ethernet packet can be from 64 to 1518 bytes in length.Default Gateway - The routing device used to forward all traffic that is notaddressed to a station within the local subnet.DHCP (Dynamic Host Configuration Protocol) - A protocol that lets networkadministrators centrally manage and automate the assignment of InternetProtocol (IP) addresses in an organization's network. Using the Internet’s set ofprotocol (TCP/IP), each machine that can connect to the Internet needs aunique IP address. When an organization sets up its computer users with a con-nection to the Internet, an IP address must be assigned to each machine.Without DHCP, the IP address must be entered manually at each computer and,if computers move to another location in another part of the network, a new IPaddress must be entered. DHCP lets a network administrator supervise and dis-tribute IP addresses from a central point and automatically sends a new IPaddress when a computer is plugged into a different place in the network. DHCP uses the concept of a “lease” or amount of time that a given IP addresswill be valid for a computer. The lease time can vary depending on how long auser is likely to require the Internet connection at a particular location. It’s espe-cially useful in education and other environments where users change fre-quently. Using very short leases, DHCP can dynamically reconfigure networksin which there are more computers than there are available IP addresses. DHCP supports static addresses for computers containing Web servers thatneed a permanent IP address. 111Instant Wireless®Series110on startup. These instructions search for the operating system, load it, and passcontrol to it. Bottleneck – A traffic slowdown that results when too many network nodes tryto access a single node, often a server node, at once.Bridge - A device that interconnects different networks together. Broadband - A data-transmission scheme in which multiple signals share thebandwidth of a medium. This allows the transmission of voice, data, and videosignals over a single medium. Cable television uses broadband techniques todeliver dozens of channels over one cable.Browser - A browser is an application program that provides a way to look atand interact with all the information on the World Wide Web or PC. The word“browser” seems to have originated prior to the Web as a generic term for userinterfaces that let you browse text files online. Buffer - A buffer is a shared or assigned memory area used by hardwaredevices or program processes that operate at different speeds or with differentsets of priorities. The buffer allows each device or process to operate withoutbeing held up by the other. In order for a buffer to be effective, the size of thebuffer and the algorithms for moving data into and out of the buffer need to beconsidered by the buffer designer. Like a cache, a buffer is a “midpoint hold-ing place” but exists not so much to accelerate the speed of an activity as tosupport the coordination of separate activities. Cable Modem - A device that connects a computer to the cable television net-work, which in turn connects to the Internet. Once connected, cable modemusers have a continuous connection to the Internet. Cable modems featureasymmetric transfer rates: around 36 Mbps downstream (from the Internet tothe computer), and from 200 Kbps to 2 Mbps upstream (from the computer tothe Internet).CAT 5 - ANSI/EIA (American National Standards Institute/ElectronicIndustries Association) Standard 568 is one of several standards that specify“categories” (the singular is commonly referred to as “CAT”) of twisted paircabling systems (wires, junctions, and connectors) in terms of the data ratesthat they can sustain. CAT 5 cable has a maximum throughput of 100 Mbps andis usually utilized for 100BaseTX networks.CPU (Central Processing Unit) - The computing part of the computer. Alsocalled the “processor,” it is made up of the control unit and ALU.
Dual-Band Wireless A+B Broadband Router Dynamic Routing - The ability for a router to forward data via a different routebased on the current conditions of the communications circuits. For example,it can adjust for overloaded traffic or failing lines and is much more flexiblethan static routing, which uses a fixed forwarding path.EAP (Extensible Authentication Protocol) - An IETF standard that establishesan authentication protocol for network access. Many authentication methods,including passwords, certificates, and smart cards, work within this framework.EAP-TLS - One type of mutual authentication method using the ExtensibleAuthentication Protocol (EAP) and a security protocol called the TransportLayer Security (TLS). EAP-TLS uses digital certificates and is more securethan MD5 authentication, which uses passwords. EAP-TLS authentication sup-ports dynamic WEP key management.EAP-TTLS - One type of mutual authentication method using the ExtensibleAuthentication Protocol (EAP) and Tunneled Transport Layer Security (TTLS).EAP-TTLS uses a combination of certificates and another method, such aspasswords. It is more secure than MD5 authentication, which uses passwords,and less secure than EAP-TLS authentication, which exclusively uses certifi-cates. EAP-TTLS authentication supports dynamic WEP key management.Encryption - A security method that applies a specific algorithm to data inorder to alter the data’s appearance and prevent other devices from reading theinformation. Ethernet - IEEE standard network protocol that specifies how data is placedon and retrieved from a common transmission medium. Has a transfer rate of10 Mbps. Forms the underlying transport vehicle used by several upper-levelprotocols, including TCP/IP and XNS.Fast Ethernet - A 100 Mbps technology based on the 10Base-T EthernetCSMA/CD network access method.FHSS (Frequency Hopping Spread Spectrum) - FHSS continuously changes(hops) the carrier frequency of a conventional carrier several times per secondaccording to a pseudo-random set of channels. Because a fixed frequency is notused, and only the transmitter and receiver know the hop patterns, interceptionof FHSS is extremely difficult.Firewall - A firewall is a set of related programs, located at a network gatewayserver, that protects the resources of a network from users from other networks.113Instant Wireless®Series112DMZ - (DeMilitarized Zone) allows one IP address (or computer) to beexposed to the Internet. Some applications require multiple TCP/IP ports to beopen. It is recommended that you set your computer with a static IP address ifyou want to use DMZ Hosting.DNS - The Domain Name System (DNS) is the way that Internet domainnames are located and translated into Internet Protocol (IP) addresses. Adomain name is a meaningful and easy-to-remember “handle” for an Internetaddress. Domain - A subnetwork comprised of a group of clients and servers under thecontrol of one security database. Dividing LANs into domains improves per-formance and security.Download - To receive a file transmitted over a network. In a communicationssession, download means receive, and upload means transmit. Driver - A workstation or server software module that provides an interfacebetween a network interface card and the upper-layer protocol software runningin the computer; it is designed for a specific NIC, and is installed during theinitial installation of a network-compatible client or server operating system.DSSS (Direct-Sequence Spread Spectrum) - DSSS generates a redundant bitpattern for all transmitted data. This bit pattern is called a chip (or chippingcode). Even if one or more bits in the chip are damaged during transmission,statistical techniques embedded in the receiver can recover the original datawithout the need for retransmission. To an unintended receiver, DSSS appearsas low power wideband noise and is rejected (ignored) by most narrowbandreceivers. However, to an intended receiver (i.e. another wireless LAN end-point), the DSSS signal is recognized as the only valid signal, and interferenceis inherently rejected (ignored).DTIM (Delivery Traffic Indication Message) - A DTIM field is a countdownfield informing clients of the next window for listening to broadcast and mul-ticast messages. When the AP has buffered broadcast or multicast messages forassociated clients, it sends the next DTIM with a DTIM Interval value. APClients hear the beacons and awaken to receive the broadcast and multicastmessages.Dynamic IP Address - An IP address that is automatically assigned to a clientstation in a TCP/IP network, typically by a DHCP server. Network devices thatserve multiple users, such as servers and printers, are usually assigned static IPaddresses.
Dual-Band Wireless A+B Broadband Router Hardware - Hardware is the physical aspect of computers, telecommunica-tions, and other information technology devices. The term arose as a way to dis-tinguish the “box” and the electronic circuitry and components of a computerfrom the program you put in it to make it do things. The program came to beknown as the software.Hub - The device that serves as the central location for attaching wires fromworkstations. Can be passive, where there is no amplification of the signals; oractive, where the hubs are used like repeaters to provide an extension of thecable that connects to a workstation.HTTP (HyperText Transport Protocol) - The communications protocol usedto connect to servers on the World Wide Web. Its primary function is to estab-lish a connection with a Web server and transmit HTML pages to the clientbrowser.IEEE - The Institute of Electrical and Electronics Engineers. The IEEEdescribes itself as “the world's largest technical professional society—promot-ing the development and application of electrotechnology and allied sciencesfor the benefit of humanity, the advancement of the profession, and the well-being of our members.” The IEEE fosters the development of standards that often become national andinternational standards. The organization publishes a number of journals, hasmany local chapters, and has several large societies in special areas, such as theIEEE Computer Society. Infrastructure Network - An infrastructure network is a group of computersor other devices, each with a wireless adapter, connected as an 802.11 wirelessLAN. In infrastructure mode, the wireless devices communicate with eachother and to a wired network by first going through an access point. An infra-structure wireless network connected to a wired network is referred to as aBasic Service Set (BSS). A set of two or more BSS in a single network isreferred to as an Extended Service Set (ESS). Infrastructure mode is useful ata corporation scale, or when it is necessary to connect the wired and wirelessnetworks.IP Address - In the most widely installed level of the Internet Protocol (IP)today, an IP address is a 32-binary digit number that identifies each sender orreceiver of information that is sent in packets across the Internet. When yourequest an HTML page or send e-mail, the Internet Protocol part of TCP/IPincludes your IP address in the message (actually, in each of the packets if more115Instant Wireless®Series114(The term also implies the security policy that is used with the programs.) Anenterprise with an intranet that allows its workers access to the wider Internetinstalls a firewall to prevent outsiders from accessing its own private dataresources and for controlling what outside resources to which its own usershave access. Basically, a firewall, working closely with a router, examines each networkpacket to determine whether to forward it toward its destination.Firmware - Code that is written onto read-only memory (ROM) or program-mable read-only memory (PROM). Once firmware has been written onto theROM or PROM, it is retained even when the device is turned off.Fragmentation - Breaking a packet into smaller units when transmitting overa network medium that cannot support the original size of the packet. FTP (File Transfer Protocol) - A protocol used to transfer files over a TCP/IPnetwork (Internet, UNIX, etc.). For example, after developing the HTML pagesfor a website on a local machine, they are typically uploaded to the Web serv-er using FTP.FTP includes functions to log onto the network, list directories, and copy files.It can also convert between the ASCII and EBCDIC character codes. FTP oper-ations can be performed by typing commands at a command prompt or via anFTP utility running under a graphical interface such as Windows. FTP transferscan also be initiated from within a Web browser by entering the URL precededwith ftp://.Unlike e-mail programs in which graphics and program files have to be“attached,” FTP is designed to handle binary files directly and does not add theoverhead of encoding and decoding the data.Full Duplex - The ability of a device or line to transmit data simultaneously inboth directions.Gateway – A device that interconnects networks with different, incompatiblecommunications protocols. Half Duplex - Data transmission that can occur in two directions over a singleline, but only one direction at a time.
Dual-Band Wireless A+B Broadband Router Mbps (MegaBits Per Second) - One million bits per second; unit of measure-ment for data transmission.MD5 - A type of one-way authentication method that uses passwords. MD5authentication is not as secure as the EAP-TLS or EAP/TTLS authenticationmethods. MD5 authentication does not support dynamic WEP key manage-ment.MDI (Medium Dependent Interface) - On a network hub or switch, a MDIport, also known as an uplink port, connects to another hub or switch using astraight-through cable. To connect a MDI port to a computer, use a crossovercable.MDIX (Medium Dependent Interface Crossed) - On a network hub orswitch, a MDIX port connects to a computer using a straight-through cable.To connect a MDIX port to another hub or switch, use a crossover cable.mIRC - mIRC runs under Windows and provides a graphical interface for log-ging onto IRC servers and listing, joining, and leaving channels.Motherboard - A motherboard is the physical arrangement in a computer thatcontains the computer’s basic circuitry and components. Multicasting - Sending data to a group of nodes instead of a single destination.NAT - NAT (Network Address Translation) is the translation of an InternetProtocol address (IP address) used within one network to a different IP addressknown within another network. One network is designated the inside networkand the other is the outside. NetBEUI (NetBIOS Extended User Interface) - The transport layer forNetBIOS. NetBIOS and NetBEUI were originally part of a single protocolsuite that was later separated. NetBIOS sessions can be transported overNetBEUI, TCP/IP, and SPX/IPX protocols. NetBIOS - The native networking protocol in DOS and Windows networks.Although originally combined with its transport layer protocol (NetBEUI),NetBIOS today provides a programming interface for applications at the ses-sion layer (layer 5). NetBIOS can ride over NetBEUI, its native transport,which is not routable, or over TCP/IP and IPX/SPX, which are routable proto-cols.117Instant Wireless®Series116than one is required) and sends it to the IP address that is obtained by lookingup the domain name in the Uniform Resource Locator you requested or in thee-mail address you're sending a note to. At the other end, the recipient can seethe IP address of the Web page requestor or the e-mail sender and can respondby sending another message using the IP address it received. IPCONFIG - A utility that provides for querying, defining and managing IPaddresses within a network. A commonly used utility, under Windows NT and2000, for configuring networks with static IP addresses.IPSec (Internet Protocol Security) - A suite of protocols used to implementsecure exchange of packets at the IP layer. IPSec supports two basic modes:Transport and Tunnel. Transport encrypts the payload of each packet, leavingthe header untouched, while Tunnel mode encrypts both the header and the pay-load and is therefore more secure. IPSec must be supported on both transmit-ter and receiver and must share a public key. Tunnel mode is widely deployedin VPNs (Virtual Private Networks).IRQ (Interrupt ReQuest) - A hardware interrupt on a PC. There are 16 IRQlines used to signal the CPU that a peripheral event has started or terminated.Except for PCI devices, two devices cannot use the same line. ISM band - The FCC and their counterparts outside of the U.S. have set asidebandwidth for unlicensed use in the ISM (Industrial, Scientific and Medical)band. Spectrum in the vicinity of 2.4 GHz, in particular, is being made avail-able worldwide. This presents a truly revolutionary opportunity to place con-venient high-speed wireless capabilities in the hands of users around the globe.ISP - An ISP (Internet service provider) is a company that provides individualsand companies access to the Internet and other related services such as websitebuilding and virtual hosting. LAN - A local area network (LAN) is a group of computers and associateddevices that share a common communications line and typically share theresources of a single processor or server within a small geographic area (forexample, within an office building). Latency - The time delay between when the first bit of a packet is received andthe last bit is forwarded.MAC Address - The MAC (Media Access Control) address is a unique num-ber assigned by the manufacturer to any Ethernet networking device, such as anetwork adapter, that allows the network to identify it at the hardware level.
Dual-Band Wireless A+B Broadband Router 119Instant Wireless®Series118Packet - A unit of data routed between an origin and a destination in a network.Packet Filtering - Discarding unwanted network traffic based on its originat-ing address or range of addresses or its type (e-mail, file transfer, etc.). Partitioning - To divide a resource or application into smaller pieces. Passphrase - Used much like a password, a passphrase simplifies the WEPencryption process by automatically generating the WEP encryption keys forLinksys products.PC Card - A credit-card sized removable module that contains memory, I/O,or a hard disk. PCI (Peripheral Component Interconnect) - A peripheral bus commonly usedin PCs, Macintoshes and workstations. It was designed primarily by Intel andfirst appeared on PCs in late 1993. PCI provides a high-speed data pathbetween the CPU and peripheral devices (video, disk, network, etc.). There aretypically three or four PCI slots on the motherboard. In a Pentium PC, there isgenerally a mix of PCI and ISA slots or PCI and EISA slots. Early on, the PCIbus was known as a “local bus.”PCI provides “plug-and-play” capability, automatically configuring the PCIcards at startup. When PCI is used with the ISA bus, the only thing that is gen-erally required is to indicate in the CMOS memory which IRQs are already inuse by ISA cards. PCI takes care of the rest.PCI allows IRQs to be shared, which helps to solve the problem of limited IRQsavailable on a PC. For example, if there were only one IRQ left over after ISAdevices were given their required IRQs, all PCI devices could share it. In a PCI-only machine, there cannot be insufficient IRQs, as all can be shared.PCMCIA - The PCMCIA (Personal Computer Memory Card InternationalAssociation) is an industry group organized in 1989 to promote standards for acredit card-size memory or I/O device that would fit into a personal computer,usually a notebook or laptop computer. Ping (Packet INternet Groper) - An Internet utility used to determine whethera particular IP address is online. It is used to test and debug a network by send-ing out a packet and waiting for a response.NetBIOS computers are identified by a unique 15-character name, andWindows machines (NetBIOS machines) periodically broadcast their namesover the network so that Network Neighborhood can catalog them. For TCP/IPnetworks, NetBIOS names are turned into IP addresses via manual configura-tion in an LMHOSTS file or a WINS server.There are two NetBIOS modes. The Datagram mode is the fastest mode, butdoes not guarantee delivery. It uses a self-contained packet with send andreceive name, usually limited to 512 bytes. If the recipient device is not listen-ing for messages, the datagram is lost. The Session mode establishes a connec-tion until broken. It guarantees delivery of messages up to 64KB long. Network - A system that transmits any combination of voice, video, and/ordata between users. Network Mask - Also known as the “Subnet Mask.”NIC (Network Interface Card) - A board installed in a computer system, usu-ally a PC, to provide network communication capabilities to and from thatcomputer system. Also called an adapter.Node - A network junction or connection point, typically a computer or workstation.Notebook (PC) - A notebook computer is a battery-powered personal comput-er generally smaller than a briefcase that can easily be transported and conve-niently used in temporary spaces such as on airplanes, in libraries, at temporaryoffices, and at meetings. A notebook computer, sometimes called a laptop com-puter, typically weighs less than five pounds and is three inches or less in thick-ness. OFDM - Developed for wireless applications, Orthogonal Frequency DivisionMultiplexing (OFDM) technology offers superior performance-increased datarates and more reliable transmissions-than previous technologies, such asDSSS. OFDM is a scheme in which numerous signals of different frequenciesare combined to form a single signal for transmission on the medium. OFDM works by breaking one high-speed data stream into a number of lower-speed data streams, which are then transmitted in parallel. Each lower speedstream is used to modulate a subcarrier. Essentially, this creates a multi-carriertransmission by dividing a wide frequency band or channel into a number ofnarrower frequency bands or sub-channels. OFDM is also used for other appli-cations, including powerline networking.
Dual-Band Wireless A+B Broadband Router RADIUS (Remote Authentication Dial-In User Service) - A protocol used tocontrol network access. RADIUS enables servers to authenticate users, so onlylegitimate users are granted network access. RADIUS servers are frequentlyused in 802.1x implementations; however, they are not specified by the 802.1xstandard.RIP (Routing Information Protocol) - A simple routing protocol that is part ofthe TCP/IP protocol suite. It determines a route based on the smallest hop countbetween source and destination. RIP is a distance vector protocol that routine-ly broadcasts routing information to its neighboring routers.RJ-11 (Registered Jack-11) - A telephone connector that holds up to six wires.The RJ-11 is the common connector used to plug a telephone into a wall. RJ-45 - A connector similar to a telephone connector that holds up to eightwires, used for connecting Ethernet devices.Roaming - In an infrastructure mode wireless network, this refers to the abil-ity to move out of one access point's range and into another and transparentlyreassociate and reauthenticate to the new access point. This reassociation andreauthentication should occur without user intervention and ideally withoutinterruption to network connectivity. A typical scenario would be a locationwith multiple access points, where users can physically relocate from one area to another and easily maintain connectivity.Router - Protocol-dependent device that connects subnetworks together.Routers are useful in breaking down a very large network into smaller subnet-works; they introduce longer delays and typically have much lower throughputrates than bridges. RTS (Request To Send) - An RS-232 signal sent from the transmitting stationto the receiving station requesting permission to transmit. Server - Any computer whose function in a network is to provide user accessto files, printing, communications, and other services. SMTP (Simple Mail Transfer Protocol) - The standard e-mail protocol on theInternet. It is a TCP/IP protocol that defines the message format and the mes-sage transfer agent (MTA), which stores and forwards the mail.SNMP (Simple Network Management Protocol) - A widely used networkmonitoring and control protocol. Data is passed from SNMP agents, which are121Instant Wireless®Series120Plug-and-Play - The ability of a computer system to configure expansionboards and other devices automatically without requiring the user to turn offthe system during installation.POP3 (Post Office Protocol 3) - A standard mail server commonly used on theInternet. It provides a message store that holds incoming e-mail until users logon and download it. POP3 is a simple system with little selectivity. All pendingmessages and attachments are downloaded at the same time. POP3 uses theSMTP messaging protocol.Port - A pathway into and out of the computer or a network device such as aswitch or router. For example, the serial and parallel ports on a personal com-puter are external sockets for plugging in communications lines, modems, andprinters. Port Mirroring - Port mirroring, also known as a roving analysis port, is amethod of monitoring network traffic that forwards a copy of each incomingand outgoing packet from one port of a network switch to another port wherethe packet can be studied. A network administrator uses port mirroring as adiagnostic tool or debugging feature, especially when fending off an attack. Itenables the administrator to keep close track of switch performance and alter itif necessary. Port mirroring can be managed locally or remotely. PPPoE (Point to Point Protocol over Ethernet) - PPPoE is a method for theencapsulation of PPP packets over Ethernet frames from the user to the ISPover the Internet. One reason PPPoE is preferred by ISPs is because it providesauthentication (username and password) in addition to data transport. A PPPoEsession can be initiated by either a client application residing on a PC, or byclient firmware residing on a modem or router.PPTP (Point-to-Point Tunneling Protocol) - A protocol which allows thePoint to Point Protocol (PPP) to be tunneled through an IP network. PPTP doesnot specify any changes to the PPP protocol but rather describes a “tunnelingservice” for carrying PPP (a tunneling service is any network service enabledby tunneling protocols such as PPTP, L2F, L2TP, and IPSEC tunnel mode). One example of a tunneling service is secure access from a remote small office net-work to a headquarters corporate intranet via a Virtual Private Network (VPN)that traverses the Internet. However, tunneling services are not restricted tocorporate environments and may also be used for personal (i.e., non-business)applications.
Dual-Band Wireless A+B Broadband Router Subnet Mask - The method used for splitting IP networks into a series of sub-groups, or subnets. The mask is a binary pattern that is matched up with the IPaddress to turn part of the host ID address field into a field for subnets. Swapping - Replacing one segment of a program in memory with another andrestoring it back to the original when required. Switch – 1. A data switch connects computing devices to host computers,allowing a large number of devices to share a limited number of ports. 2. Adevice for making, breaking, or changing the connections in an electrical cir-cuit.TCP (Transmission Control Protocol) - A method (protocol) used along withthe IP (Internet Protocol) to send data in the form of message units (datagram)between network devices over a LAN or WAN. While IP takes care of handlingthe actual delivery of the data (routing), TCP takes care of keeping track of the individual units of data (called packets) that a message is divided into for effi-cient delivery over the network. TCP is known as a “connection oriented” pro-tocol due to requiring the receiver of a packet to return an acknowledgment ofreceipt to the sender of the packet resulting in transmission control.TCP/IP (Transmission Control Protocol/Internet Protocol) - The basic com-munication language or set of protocols for communications over a network(developed specifically for the Internet). TCP/IP defines a suite or group ofprotocols and not only TCP and IP.Telnet - A terminal emulation protocol commonly used on the Internet andTCP/IP-based networks. It allows a user at a terminal or computer to log ontoa remote device and run a program.TFTP (Trivial File Transfer Protocol) - A version of the TCP/IP FTP protocolthat has no directory or password capability.Throughput - The amount of data moved successfully from one place to anoth-er in a given time period.Topology - A network’s topology is a logical characterization of how thedevices on the network are connected and the distances between them. Themost common network devices include hubs, switches, routers, and gateways.Most large networks contain several levels of interconnection, the most impor-tant of which include edge connections, backbone connections, and wide-areaconnections.123Instant Wireless®Serieshardware and/or software processes reporting activity in each network device(hub, router, bridge, etc.) to the workstation console used to oversee the net-work. The agents return information contained in a MIB (ManagementInformation Base), which is a data structure that defines what is obtainablefrom the device and what can be controlled (turned off, on, etc.).Software - Instructions for the computer. A series of instructions that performsa particular task is called a “program.” The two major categories of software are“system software” and “application software.” System software is made up of control programs such as the operating system and database management sys-tem (DBMS). Application software is any program that processes data for theuser.A common misconception is that software is data. It is not. Software tells thehardware how to process the data.SOHO (Small Office/Home Office) - Market segment of professionals whowork at home or in small offices.Spread Spectrum - Spread Spectrum technology is a wideband radio frequen-cy technique developed by the military for use in reliable, secure, mission-crit-ical communications systems. It is designed to trade off bandwidth efficiencyfor reliability, integrity, and security. In other words, more bandwidth is con-sumed than in the case of narrowband transmission, but the trade off producesa signal that is, in effect, louder and thus easier to detect, provided that thereceiver knows the parameters of the spread-spectrum signal being broadcast.If a receiver is not tuned to the right frequency, a spread-spectrum signal lookslike background noise. There are two main alternatives, Direct SequenceSpread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).Static IP Address - A permanent IP address that is assigned to a node in aTCP/IP network. Static Routing - Forwarding data in a network via a fixed path. Static routingcannot adjust to changing line conditions as can dynamic routing. Storage - The semi-permanent or permanent holding place for digital data. STP (Shielded Twisted Pair) - Telephone wire that is wrapped in a metalsheath to eliminate external interference.122
Dual-Band Wireless A+B Broadband Router WAN (Wide Area Network) - A communications network that covers a rela-tively large geographic area, consisting of two or more LANs. Broadband com-munication over the WAN is often through public networks such as thetelephone (DSL) or cable systems, or through leased lines or satellites. In itsmost basic definition, the Internet could be considered a WAN.WEP (Wired Equivalent Privacy) - A data privacy mechanism based on a 64-bit or 128-bi shared key algorithm, as described in the IEEE 802.11 standard. WINIPCFG - Configuration utility based on the Win32 API for querying,defining, and managing IP addresses within a network. A commonly used util-ity for configuring networks with static IP addresses.WLAN (Wireless Local Area Network) - A group of computers and associat-ed devices that communicate with each other wirelessly.Workgroup - Two or more individuals that share files and databases. 125Instant Wireless®SeriesTX Rate – Transmission Rate.UDP (User Datagram Protocol) - A method (protocol) used along with the IP(Internet Protocol) to send data in the form of message units (datagram)between network devices over a LAN or WAN. While IP takes care of handlingthe actual delivery of the data (routing), UDP takes care of keeping track of theindividual units of data (called packets) that a message is divided into for effi-cient delivery over the network. UDP is known as a “connection-less” protocoldue to NOT requiring the receiver of a packet to return an acknowledgment ofreceipt to the sender of the packet (as opposed to TCP).Upgrade - To replace existing software or firmware with a newer version. Upload - To send a file transmitted over a network. In a communications ses-sion, upload means transmit, and download means receive. URL (Uniform Resource Locator) - The address that defines the route to a fileon the Web or any other Internet facility. URLs are typed into the browser toaccess Web pages, and URLs are embedded within the pages themselves to pro-vide the hypertext links to other pages.UTP - Unshielded twisted pair is the most common kind of copper telephonewiring. Twisted pair is the ordinary copper wire that connects home and manybusiness computers to the telephone company. To reduce crosstalk or electro-magnetic induction between pairs of wires, two insulated copper wires aretwisted around each other. Each signal on twisted pair requires both wires.Since some telephone sets or desktop locations require multiple connections,twisted pair is sometimes installed in two or more pairs, all within a singlecable. VPN (Virtual Private Network) - A technique that allows two or more LANs tobe extended over public communication channels by creating private commu-nication subchannels (tunnels). Effectively, these LANs can use a WAN as asingle large “virtually private” LAN. This removes the need to use leased linesfor WAN communications through secure use of a publicly available WAN(such as the Internet). Examples of VPN technology are: PPTP (Point to PointTunneling Protocol), L2TP (Layer 2 Tunneling Protocol), and IPSec (InternetProtocol Security).124
Dual-Band Wireless A+B Broadband Router Network Protocols802.11a: TCP/IP, NetBEUI, IPX/SPX802.11b: TCP/IP, NetBEUI, IPX/SPXLED Indicators Power, DiagInternet: Link/Act, 100LAN: Link/Act, Full/Col, 100802.11a: Act, Link802.11b: Act, LinkDimensions 7.32" x 1.89" x 6.89"(186 mm x 48 mm x 175 mm)Unit Weight 14.1 oz. (0.4 kg)Power External, 5V DC, 2.5 ACertifications FCC Class B, CE MarkOperating Temp. 0°C to 40°C (32°F to 104°F)Storage Temp. -20°C to 70°C (-4°F to 158°F)Operating Humidity 10% to 85%, Non-CondensingStorage Humidity 5% to 90%, Non-Condensing127Instant Wireless®Series126EnvironmentalAppendix F:SpecificationsStandards IEEE 802.3,IEEE 802.3u, IEEE 802.11a,IEEE 802.11bPortsInternet: One 10/100 RJ-45 Port for Cable/DSL ModemLAN: Four 10/100 RJ-45 Switched PortsOne Power PortButton One Reset ButtonCabling Type Category 5 Ethernet Network Cable or betterTransmit Power 802.11a:15 dBm802.11b:12 dBmReceive Sensitivity 802.11a: 1 Mbps: -93 dBm2 Mbps: -91 dBm5.5 Mbps: -88 dBm11 Mbps: -84 dBm802.11b: 6 Mbps: -86dBm9 Mbps: -85dBm12 Mbps:-84dBm18 Mbps:-82dBm24 Mbps: -80dBm36 Mbps: -75dBm48 Mbps: -68dBm54 Mbps: -67dBmModulation802.11a: BPSK, QPSK, 16-QAM, 64-QAM802.11b: CCK, QPSK, BPSK
Dual-Band Wireless A+B Broadband Router Appendix H:Contact InformationFor help with the installation or operation of the Dual-Band Wireless A+BBroadband Router, contact Linksys Technical Support at one of the phone num-bers or Internet addresses below.Sales Information 800-546-5797 (1-800-LINKSYS)Technical Support 800-326-7114RMA Issues 949-271-5461Fax 949-265-6655Email support@linksys.comWeb site http://www.linksys.comFTP site ftp://ftp.linksys.com129Instant Wireless®Series128Appendix G:WarrantyInformationBE SURE TO HAVE YOUR PROOF OF PURCHASE AND A BARCODEFROM THE PRODUCT'S PACKAGING ON HAND WHEN CALLING.RETURN REQUESTS CANNOT BE PROCESSED WITHOUT PROOF OFPURCHASE. IN NO EVENT SHALL LINKSYS’S LIABILITY EXCEED THE PRICEPAID FOR THE PRODUCT FROM DIRECT, INDIRECT, SPECIAL, INCI-DENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM THEUSE OF THE PRODUCT, ITS ACCOMPANYING SOFTWARE, OR ITSDOCUMENTATION. LINKSYS DOES NOT OFFER REFUNDS FOR ANYPRODUCT. LINKSYS OFFERS CROSS SHIPMENTS, A FASTER PROCESS FOR PRO-CESSING AND RECEIVING YOUR REPLACEMENT. LINKSYS PAYSFOR UPS GROUND ONLY. ALL CUSTOMERS LOCATED OUTSIDE OFTHE UNITED STATES OF AMERICA AND CANADA SHALL BE HELDRESPONSIBLE FOR SHIPPING AND HANDLING CHARGES. PLEASECALL LINKSYS FOR MORE DETAILS.
Federal Communication Commission Interference StatementThis equipment has been tested and found to comply with the limits for a Class B digital device,pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonableprotection against harmful interference in a residential installation. This equipment generates,uses and can radiate radio frequency energy and, if not installed and used in accordance withthe instructions, may cause harmful interference to radio communications. However, there is noguarantee that interference will not occur in a particular installation. If this equipment does causeharmful interference to radio or television reception, which can be determined by turning theequipment off and on, the user is encouraged to try to correct the interference by one of thefollowing measures:- Reorient or relocate the receiving antenna.- Increase the separation between the equipment and receiver.- Connect the equipment into an outlet on a circuit different from that to which the receiver isconnected.- Consult the dealer or an experienced radio/TV technician for help.FCC Caution: To assure continued compliance, (example - use only shielded interface cableswhen connecting to computer or peripheral devices) any changes or modifications not expresslyapproved by the party responsible for compliance could void the user's authority to operate thisequipment.This device complies with Part 15 of the FCC Rules. Operation is subject to the following twoconditions: (1) This device may not cause harmful interference, and (2) this device must acceptany interference received, including interference that may cause undesired operation.IMPORTANT NOTE:FCC Radiation Exposure Statement:This equipment complies with FCC radiation exposure limits set forth for an uncontrolledenvironment. This equipment should be installed and operated with minimum distance 20cmbetween the radiator & your body.The use of this device is restricted to indoor operations, and that outdoor operations are prohibited under FCC rules and regulations.
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