Aerohive Networks HIVEAP340 802.11 a/b/g/n access point User Manual Aerohive Deployment Guide
Aerohive Networks, Inc. 802.11 a/b/g/n access point Aerohive Deployment Guide
Contents
Users Manual 1
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| Document Description | Users Manual 1 |
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| Document Type | User Manual |
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| Date Submitted | 2008-09-12 00:00:00 |
| Date Available | 2008-09-12 00:00:00 |
| Creation Date | 2008-08-15 14:44:55 |
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| Document Title | Aerohive Deployment Guide |
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| Document Author: | Aerohive Technical Publications |
Aerohive Deployment Guide Aerohive Deployment Guide For HiveAP and HiveManager Devices Aerohive Technical Publications Copyright Notice Copyright © 2008 Aerohive Networks, Inc. All rights reserved. Aerohive Networks, the Aerohive Networks logo, HiveOS, HiveAP, and HiveManager are trademarks of Aerohive Networks, Inc. All other trademarks and registered trademarks are the property of their respective companies. Information in this document is subject to change without notice. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without receiving written permission from: Aerohive Networks, Inc. 3150-C Coronado Drive Santa Clara, CA 95054 P/N 330002-06, Rev. A HiveAP Compliance Information HiveAP Compliance Information Federal Communication Commission Interference Statement This 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 reasonable protection 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 with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following 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 is connected • Consult the dealer or an experienced radio/TV technician for help FCC Caution: Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate this equipment. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. Important: FCC Radiation Exposure Statement This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with a minimum distance of 20 centimeters (8 inches) between the radiator and your body. This transmitter must not be colocated or operating in conjunction with any other antenna or transmitter. Wireless 5 GHz Band Statements High power radars are allocated as primary users (meaning they have priority) of the 5250-5350 MHz and 5650-5850 MHz bands. These radars could cause interference and/or damage to the HiveAP when used in Canada. The term "IC" before the radio certification number only signifies that Industry Canada technical specifications were met. Industry Canada - Class B This digital apparatus does not exceed the Class B limits for radio noise emissions from digital apparatus as set out in the interference-causing equipment standard entitled "Digital Apparatus," ICES-003 of Industry Canada. Cet appareil numérique respecte les limites de bruits radioélectriques applicables aux appareils numériques de Classe B prescrites dans la norme sur le matériel brouilleur: "Appareils Numériques," NMB-003 édictée par l'Industrie. Wi-Fi Certification The Wi-Fi CERTIFIED™ Logo is a certification mark of the Wi-Fi Alliance®. The Aerohive HiveAP 20 ag has been certified for WPA™, WPA2™, WMM® (Wi-Fi Multimedia™), WMM Power Save, and the following types of EAP (Extensible Authentication Protocol): • EAP-TLS • EAP-TTLS/MSCHAPv2 • PEAPv0/EAP-MSCHAPv2 • PEAPv1/EAP-GTC • EAP-SIM EC Conformance Declaration Marking by the above symbol indicates compliance with the Essential Requirements of the R&TTE Directive of the European Union (1999/5/ EC). This equipment meets the following conformance standards: • EN 60950-1 (IEC 60950-1) - Product Safety • EN 301 893 - Technical requirements for 5 GHz radio equipment • EN 300 328 - Technical requirements for 2.4 GHz radio equipment • EN 301 489-1 / EN 301 489-17 - EMC requirements for radio equipment Countries of Operation and Conditions of Use in the European Community HiveAPs are intended to be operated in all countries of the European Community. Requirements for indoor vs. outdoor operation, license requirements and allowed channels of operation apply in some countries as described below. • Before operating a HiveAP, the admin or installer must properly enter the current country of operation in the command line interface as described in "Appendix A Country Codes" on page 177. Note to U.S. model owners: To comply with U.S. FCC regulations, the country selection function has been completely removed from all U.S. models. The above function is for non-U.S. models only. • HiveAPs automatically limit the allowable channels determined by the current country of operation. Incorrectly entering the country of operation might result in illegal operation and cause harmful interference to other systems. The admin is obligated to ensure HiveAPs are operating according to the channel limitations, indoor/outdoor restrictions and license requirements for each European Community country as described in this section. • HiveAPs can be operated indoors or outdoors in all countries of the European Community using the 2.4 GHz band: Channels 1 - 13, except where noted below. – In Italy, you must apply for a license from the national spectrum authority to operate a HiveAP outdoors. – In Belgium outdoor operation is only permitted using the 2.46 2.4835 GHz band: Channel 13. – In France outdoor operation is only permitted using the 2.4 2.454 GHz band: Channels 1 - 7. • HiveAPs are restricted to indoor use when operated in the European Community using the 5.15 - 5.25 GHz band: Channels 36, 40, 44, 48. Because the frequency ranges 5.25 – 5.35 and 5.47 – 5.725 are affected by DFS (Dynamic Frequency Selection), HiveAPs block channels 52, 56, 60, 64, and 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140. Aerohive HIVEAP COMPLIANCE INFORMATION The availability of some specific channels and/or operational frequency bands are country dependent and are firmware programmed at the factory to match the intended destination. The firmware setting is not accessible by the end user. • The 5 GHz Turbo Mode feature is not allowed for operation in any European Community country. You can find the current setting for this feature in two places. In the HiveManager GUI, click Configuration > Network Objects> Radio Profiles > profile > Advanced. In the HiveAP CLI, enter this command: show radio profile profile. By default, Turbo Mode is disabled. Declaration of Conformity in Languages of the European Community English Hereby, Edgecore, declares that this Radio LAN device is in compliance with the essential requirements and other relevant provisions of Directive 1999/5/EC. Finnish Valmistaja Edgecore vakuuttaa täten että Radio LAN device tyyppinen laite on direktiivin 1999/5/EY oleellisten vaatimusten ja sitä koskevien direktiivin muiden ehtojen mukainen. Dutch Hierbij verklaart Edgecore dat het toestel Radio LAN device in overeenstemming is met de essentiële eisen en de andere relevante bepalingen van richtlijn 1999/5/EG. Bij deze Edgecore dat deze Radio LAN device voldoet aan de essentiële eisen en aan de overige relevante bepalingen van Richtlijn 1999/5/EC. French Swedish Danish German Par la présente Edgecore déclare que cet appareil Radio LAN est conforme aux exigences essentielles et aux autres dispositions relatives à la directive 1999/5/CE. Härmed intygar Edgecore att denna Radio LAN device står I överensstämmelse med de väsentliga egenskapskrav och övriga relevanta bestämmelser som framgår av direktiv 1999/5/EG. Undertegnede Edgecore erklærer herved, at følgende udstyr Radio LAN device overholder de væsentlige krav og øvrige relevante krav i direktiv 1999/5/EF. HiveAP 20 ag Safety Compliance Power Cord Safety Please read the following safety information carefully before installing a HiveAP. Warning: Installation and removal of HiveAPs must be carried out by qualified personnel only. • HiveAPs must be connected to an earthed (grounded) outlet to comply with international safety standards. • Do not connect HiveAPs to an A.C. outlet (power supply) without an earth (ground) connection. • The appliance coupler (the connector to the unit and not the wall plug) must have a configuration for mating with an EN 60320/IEC 320 appliance inlet. • The socket outlet must be near the HiveAP and easily accessible. You can only remove power from a HiveAP by disconnecting the power cord from the outlet. • HiveAPs operate under SELV (Safety Extra Low Voltage) conditions according to IEC 60950. The conditions are only maintained if the equipment to which they are connected also operates under SELV conditions. • A HiveAP receiving power through its PoE (Power over Ethernet) interface must be in the same building as the equipment from which it receives power. France and Peru only: HiveAPs cannot be powered from IT* supplies. If your supplies are of IT type, then a HiveAP must be powered by 230 V (2P+T) via an isolation transformer ratio 1:1, with the secondary connection point labelled Neutral, connected directly to earth (ground). * Impédance à la terre Important! Before making connections, make sure you have the correct cord set. Check it (read the label on the cable) against the description on the following page. Power Cord Set U.S.A. and Canada Greek Italian Con la presente Edgecore dichiara che questo Radio LAN device è conforme ai requisiti essenziali ed alle altre disposizioni pertinenti stabilite dalla direttiva 1999/5/CE. Spanish Por medio de la presente Manufacturer declara que el Radio LAN device cumple con los requisitos esenciales y cualesquiera otras disposiciones aplicables o exigibles de la Directiva 1999/5/CE. Portuguese Manufacturer declara que este Radio LAN device está conforme com os requisitos essenciais e outras disposições da Directiva 1999/5/CE. Deployment Guide Minimum specifications for the flexible cord: - No. 18 AWG not longer than 2 meters, or 16 AWG - Type SV or SJ - 3-conductor Hiermit erklärt Edgecore, dass sich dieser/diese/ dieses Radio LAN device in Übereinstimmung mit den grundlegenden Anforderungen und den anderen relevanten Vorschriften der Richtlinie 1999/5/EG befindet". (BMWi) Hiermit erklärt Edgecore die Übereinstimmung des Gerätes Radio LAN device mit den grundlegenden Anforderungen und den anderen relevanten Festlegungen der Richtlinie 1999/5/EG. (Wien) The cord set must be UL-approved and CSA certified. The cord set must have a rated current capacity of at least 10 A. The attachment plug must be an earth-grounding type with NEMA 5-15P (15 A, 125 V) or NEMA 6-15 (15 A, 250 V) configuration. Denmark The supply plug must comply with Section 107-2-D1, Standard DK2-1a or DK2-5a. Switzerland The supply plug must comply with SEV/ASE 1011. U.K. The supply plug must comply with BS1363 (3-pin 13 A) and be fitted with a 5 A fuse that complies with BS1362. The mains cord must beor marked and be of type HO3VVF3GO.75 (minimum). Europe The supply plug must comply with CEE7/7 ("SCHUKO"). The mains cord must be or marked and be of type HO3VVF3GO.75 (minimum). IEC-320 receptacle. Veuillez lire attentivement les informations de sécurité relatives à l'installation d'un point d'accès HiveAP. HiveAP Compliance Information Avertissement: L'installation et la dépose de points d'accès HiveAP doivent être effectuées uniquement par un personnel qualifié. Bitte unbedingt vor dem Einbauen des HiveAP die folgenden Sicherheitsanweisungen durchlesen. • Les points d'accès HiveAP doivent être connectés sur le secteur par une prise électrique munie de terre (masse) afin de respecter les standards internationaux de sécurité. Warnung: Die Installation und der Ausbau des Geräts darf nur durch Fachpersonal erfolgen. • Ne jamais connecter des points d'accès HiveAP à une alimentation électrique non-pourvue de terre (masse). • Le boitier d'alimentation (connecté directement au point d'accès) doit être compatible avec une entrée électrique de type EN 60320/IEC 320. • Das Gerät sollte nicht an eine ungeerdete Wechselstromsteckdose angeschlossen werden. • Das Gerät muß an eine geerdete Steckdose angeschlossen werden, welche die internationalen Sicherheitsnormen erfüllt. • Der Gerätestecker (der Anschluß an das Gerät, nicht der Wandsteckdosenstecker) muß einen gemäß EN 60320/IEC 320 konfigurierten Geräteeingang haben. • La prise secteur doit se trouver à proximité du point d'accès HiveAP et facilement accessible. Vous ne pouvez mettre hors tension un point d'accès HiveAP qu'en débranchant son alimentation électrique au niveau de cette prise. • Die Netzsteckdose muß in der Nähe des Geräts und leicht zugänglich sein. Die Stromversorgung des Geräts kann nur durch Herausziehen des Gerätenetzkabels aus der Netzsteckdose unterbrochen werden. • Pour des raisons de sécurité, le point d'accès HiveAP fonctionne à une tension extrêmement basse, conformément à la norme IEC 60950. Les conditions de sécurité sont valables uniquement si l'équipement auquel le point d'accès HiveAP est raccordé fonctionne également selon cette norme. • Der Betrieb dieses Geräts erfolgt unter den SELV-Bedingungen (Sicherheitskleinstspannung) gemäß IEC 60950. Diese Bedingungen sind nur gegeben, wenn auch die an das Gerät angeschlossenen Geräte unter SELV-Bedingungen betrieben werden. • Un point d'accès HiveAP alimenté par son interface réseau Ethernet en mode POE (Power over Ethernet) doit être physiquement dans le même bâtiment que l'équipement réseau qui lui fournit l'électricité. France et Pérou uniquement: Stromkabel. Dies muss von dem Land, in dem es benutzt wird geprüft werden: U.S.A. und Kanada - Der typ SV oder SJ - 3-Leiter Der Cord muß haben eine strombelastbarkeit aus wenigstens 10 A. Dieser Stromstecker muß hat einer erdschluss mit der typ NEMA 5-15P (15A, 125V) oder NEMA 6-15P (15A, 250V) konfiguration. Cordon électrique - Il doit être agréé dans le pays d'utilisation Le cordon doit avoir reçu l'homologation des UL et un certificat de la CSA. Danemark Dieser Stromstecker muß die ebene 107-2-D1, der standard DK2-1a oder DK2-5a Bestimmungen einhalten. Schweiz Dieser Stromstecker muß die SEV/ASE 1011Bestimmungen einhalten. Europe Europe Das Netzkabel muß vom Typ HO3VVF3GO.75 (Mindestanforderung) sein und die Aufschrift oder tragen. Les spécifications minimales pour un cable flexible - AWG No. 18, ou AWG No. 16 pour un cable de longueur inférieure à 2 mètres. - Type SV ou SJ - 3 conducteurs Le cordon doit être en mesure d'acheminer un courant nominal d'au moins 10 A. La prise femelle de branchement doit être du type à mise à la terre (mise à la masse) et respecter la configuration NEMA 5-15P (15 A, 125 V) ou NEMA 615P (15 A, 250 V). Danemark La prise mâle d'alimentation doit respecter la section 107-2 D1 de la norme DK2 1a ou DK2 5a. Suisse La prise mâle d'alimentation doit respecter la norme SEV/ASE 1011. Europe La prise secteur doit être conforme aux normes CEE 7/7 ("SCHUKO"). Das Minimum spezifikation fur der Cord sind: - Nu. 18 AWG - nicht mehr als 2 meter, oder 16 AWG. Un point d'accès HiveAP ne peut pas être alimenté par un dispositif à impédance à la terre. Si vos alimentations sont du type impédance à la terre, alors le point d'accès HiveAP doit être alimenté par une tension de 230 V (2P+T) via un transformateur d'isolement à rapport 1:1, avec le neutre connecté directement à la terre (masse). Etats-Unis et Canada Der Cord muß das UL gepruft und war das CSA beglaubigt. Der Netzstecker muß die Norm CEE 7/7 erfüllen ("SCHUKO"). LE cordon secteur doit porter la mention ou et doit être de type HO3VVF3GO.75 (minimum). Liability Disclaimer Installation of Aerohive equipment must comply with local and national electrical codes and with other regulations governing this type of installation. Aerohive Networks, its channel partners, resellers, and distributors assume no liability for personal injury, property damage, or violation of government regulations that may arise from failing to comply with the instructions in this guide and appropriate electrical codes. Aerohive Contents Chapter 1 Preparing for a WLAN Deployment ...............................................9 Assessing Your Requirements .............................................................................10 Planning ......................................................................................................10 Upgrading from Existing Wi-Fi ................................................................................... 10 New WLAN Deployment ........................................................................................... 11 Site Surveys......................................................................................................... 12 Budgeting Wi-Fi: The Chicken and Egg Problem .............................................................. 13 Planning Tools ................................................................................................. 13 Associated Access Point Costs ............................................................................... 14 Bandwidth Assumptions for Wi-Fi ............................................................................... 14 Overcoming Physical Impediments.............................................................................. 15 Preparing the Wired Network for Wireless .................................................................... 17 Operational Considerations................................................................................18 Tuning ............................................................................................................... 18 Troubleshooting.................................................................................................... 18 Management ........................................................................................................ 18 Deploying with Confidence....................................................................................... 18 Basic Wi-Fi Concepts .......................................................................................19 Chapter 2 The HiveAP 20 ag Platform....................................................... 23 HiveAP 20 Product Overview ..............................................................................24 Ethernet and Console Ports ...................................................................................... 26 Status LEDs ......................................................................................................... 27 Antennas ............................................................................................................ 28 Mounting the HiveAP 20....................................................................................29 Ceiling Mount....................................................................................................... 29 Surface Mount ...................................................................................................... 30 Device, Power, and Environmental Specifications.....................................................31 Chapter 3 The HiveAP 28 Outdoor Platform ............................................... 33 HiveAP 28 Product Overview ..............................................................................34 Ethernet Port ....................................................................................................... 35 Power Connector .................................................................................................. 36 Antennas ............................................................................................................ 37 Deployment Guide Contents Mounting the HiveAP 28 and Attaching Antennas ......................................................38 Pole Mount .......................................................................................................... 39 Strand Mount ....................................................................................................... 40 Surface Mount ...................................................................................................... 41 Attaching Antennas................................................................................................ 42 Connecting Antennas Directly to the HiveAP 28.......................................................... 42 Mounting Antennas Separately .............................................................................. 42 Device, Power, and Environmental Specifications.....................................................44 Chapter 4 The HiveAP 340 Platform......................................................... 45 HiveAP 340 Product Overview.............................................................................46 Ethernet and Console Ports ...................................................................................... 48 Smart PoE ...................................................................................................... 49 Aggregate and Redundant Interfaces ...................................................................... 49 Console Port ................................................................................................... 51 Status LEDs ......................................................................................................... 52 Antennas ............................................................................................................ 52 MIMO ............................................................................................................ 53 Using MIMO with Legacy Clients............................................................................. 55 Mounting the HiveAP 340 ..................................................................................56 Ceiling Mount....................................................................................................... 56 Locking the HiveAP 340 ...................................................................................... 57 Surface Mount ...................................................................................................... 58 Device, Power, and Environmental Specifications.....................................................59 Chapter 5 The HiveManager Platform ....................................................... 61 Product Overview ...........................................................................................62 Ethernet and Console Ports ...................................................................................... 63 Status LEDs ......................................................................................................... 64 Rack Mounting the HiveManager..........................................................................65 Device, Power, and Environmental Specifications.....................................................66 Chapter 6 The High Capacity HiveManager Platform ..................................... 67 Product Overview ...........................................................................................68 Rack Mounting the High Capacity HiveManager ........................................................70 Replacing Power Supplies..................................................................................73 Replacing Hard Disk Drives ................................................................................74 Device, Power, and Environmental Specifications.....................................................75 Aerohive Chapter 7 Using HiveManager ................................................................. 77 Installing and Connecting to the HiveManager GUI ....................................................79 Introduction to the HiveManager GUI ....................................................................82 Cloning Configurations ............................................................................................ 83 Multiselecting ...................................................................................................... 83 Sorting Displayed Data ............................................................................................ 84 HiveManager Configuration Workflow ...................................................................85 Updating Software on HiveManager ......................................................................86 Updating HiveOS Firmware ................................................................................87 Updating HiveAPs in a Mesh Environment...................................................................... 88 Chapter 8 HiveManager Configuration Examples.......................................... 89 Example 1: Mapping Locations and Installing HiveAPs ................................................91 Setting Up Topology Maps ........................................................................................ 91 Preparing the HiveAPs ............................................................................................ 94 Using SNMP ..................................................................................................... 94 Using MAC Addresses.......................................................................................... 95 Example 2: Defining Network Objects and MAC Filters ...............................................97 Defining a MAC OUI ................................................................................................ 97 Mapping the MAC OUI and Services to Aerohive Classes ................................................ 98 Defining VLANs ................................................................................................... 100 Creating IP Addresses ........................................................................................... 101 Creating a MAC Filter ........................................................................................... 103 Example 3: Providing Guest Access .................................................................... 104 Guest Access with Preshared Keys ............................................................................ Guest Access with Captive Web Portal ....................................................................... Captive Web Portal with External DHCP and DNS Servers ............................................ Captive Web Portal with Internal DHCP and DNS Servers ............................................. Customizing the Registration Page ....................................................................... Loading Customized Captive Web Portal Files.......................................................... Defining a Captive Web Portal ............................................................................ 104 105 105 107 108 111 112 Example 4: Creating User Profiles...................................................................... 113 Example 5: Setting SSIDs................................................................................. 117 Example 6: Setting Management Service Parameters ............................................... 120 Example 7: Defining AAA RADIUS Settings............................................................. 123 Example 8: Creating Hives............................................................................... 125 Deployment Guide Contents Example 9: Creating WLAN Policies .................................................................... 126 WLANpolicy-hq1.................................................................................................. WLANpolicy-hq1 (Page 1) .................................................................................. WLANpolicy-hq1 (Page 2) .................................................................................. WLANpolicy-hq1 (Page 3) .................................................................................. 126 126 128 131 WLANpolicy-hq2.................................................................................................. 134 WLANpolicy-branch1 ............................................................................................ 134 Example 10: Assigning Configurations to HiveAPs.................................................... 135 Chapter 9 HiveOS .............................................................................. 141 Common Default Settings and Commands............................................................. 142 Configuration Overview .................................................................................. 143 Device-Level Configurations ................................................................................... 143 Policy-Level Configurations .................................................................................... 144 HiveOS Configuration File Types........................................................................ 145 Chapter 10 Deployment Examples (CLI) .................................................. 149 Example 1: Deploying a Single HiveAP................................................................. 150 Example 2: Deploying a Hive ............................................................................ 153 Example 3: Using IEEE 802.1X Authentication ........................................................ 158 Example 4: Applying QoS ................................................................................ 161 Example 5: Loading a Bootstrap Configuration....................................................... 167 CLI Commands for Examples ............................................................................ 170 Commands for Example 1 ...................................................................................... 170 Commands for Example 2 ...................................................................................... 170 Commands for Example 3 ...................................................................................... 171 Commands for Example 4 ...................................................................................... 172 Commands for Example 5 ...................................................................................... 174 Chapter 11 Traffic Types .................................................................... 175 Appendix A Country Codes .................................................................. 177 Aerohive Chapter 1 Preparing for a WLAN Deployment To ensure a smooth WLAN deployment, you need to begin with a bit of planning. A straightforward review of your deployment plan before you begin will result in optimal results more quickly. The goals of this chapter are to assist you in assessing your readiness for WLAN implementation and to provide tips and tricks to resolve any issues that might arise in your environment. The chapter covers the following topics: • "Assessing Your Requirements" on page 10 • "Planning" on page 10 • • "Upgrading from Existing Wi-Fi" on page 10 • "New WLAN Deployment" on page 11 • "Site Surveys" on page 12 • "Budgeting Wi-Fi: The Chicken and Egg Problem" on page 13 • "Bandwidth Assumptions for Wi-Fi" on page 14 • "Overcoming Physical Impediments" on page 15 "Operational Considerations" on page 18 • "Preparing the Wired Network for Wireless" on page 17 • "Deploying with Confidence" on page 18 Although this guide assumes an understanding of corporate data networking, previous experience with LAN configuration and deployment, and some basic Wi-Fi understanding, the chapter concludes with a section that provides additional support for the preceding sections: "Basic Wi-Fi Concepts" on page 19. Note: This guide assumes an understanding of corporate data networking and past experience with LAN configuration and deployment. It also assumes some basic Wi-Fi understanding. Deployment Guide Chapter 1 Preparing for a WLAN Deployment ASSESSING YOUR REQUIREMENTS To get started with your Aerohive WLAN installation, examine the basic requirements of your implementation. First, consider who your stakeholders are and take the time to fully understand their access requirements. Talk to department managers within your organization and make sure everyone has documented the full complement of potential users of your network. Check if the applications are standard employee applications or if there are other requirements, such as access for guests or consultants. Next, make a complete list of the application types that your Aerohive network will need to support. Begin your list with mission-critical applications, paying special attention to those that generate high levels of traffic and those requiring deterministic behavior. Identify applications with heavy data requirements and expected service levels. Demanding applications such as voice and video will require a higher density of access points. Many enterprises are investigating the potential of VoWLAN (Voice over WLAN) in the hopes of integrating mobile phones and IP-PBX systems. Doing so requires an evaluation of other data transmission types that can disrupt the quality of voice conversations. Because voice traffic is sensitive to network jitter and latency, an inadequate number of access points can degrade quality. To the user, excessive jitter and delay can cause clipped conversations or dropped calls. Additional quality and reliability issues might arise when transmitting video, such as for training video or surveillance operations, because of the sheer size of the data stream. Other applications such as network backup and file transfers can also have an impact on the network. Therefore, take into account any bandwidth-intensive applications if you expect your mobile workforce to be accessing the WLAN while these applications or services are occurring. Considering the above issues will result in a more informed—and therefore more successful—deployment plan. PLANNING This section reviews the fundamental elements for planning your WLAN deployment. This includes conducting a site survey, both for an upgrade from an existing WLAN and for a completely fresh—or greenfield—deployment. Upgrading from Existing Wi-Fi If you are upgrading to Aerohive from an existing WLAN, you already have plenty of data about how your current network is performing. This information can lead to more informed decisions about your new implementation. To begin, perform a quick site survey with the existing access points in place. If they are less than three years old and support 802.11g, their coverage and capacity should be equivalent or slightly lower than the Aerohive 802.11g radio. If the coverage is correct and has the appropriate density for your deployment, then you simply need to replace one set of access points with a new set of HiveAPs. However, this scenario is rare because network upgrades are usually done to improve capacity and to augment the existing layout with a denser deployment of access points. Be sure to take note whether your existing network uses "fat" or "thin" APs (access points). A "fat" AP is an autonomous or standalone access point, which contains the intelligence and capability to connect to any Ethernet switch. With a "thin" AP, most of the intelligence has been removed and replaced in a centralized WAN controller. A fat upgrade to Aerohive HiveAPs is very natural. Generally, with fat APs you simply need to unplug the existing ones and plug in the new HiveAPs and provision them. With this approach, you can maintain or enhance all existing VLANs and security policies. This is a huge advantage over migrating from fat AP to controller-based solutions because you typically need to re-architect the network. 10 Aerohive PLANNING Upgrading from a thin AP solution is also easy. However, because a thin AP makes use of an overlay tunneled network, you sometimes have to add a local VLAN for access or use tunnels to replicate the overlay network. However, because using VLANs rather than tunnels provides significant performance and scalability advantages, that is clearly the recommended path. New WLAN Deployment In a new—or greenfield—WLAN deployment, you do not have the benefit of an existing network for testing and analysis, which makes your job a bit more difficult. In this case, the following key questions are critical to the proper design of your WLAN: • How many users will need wireless service and what applications will they use? Determining the scope of your WLAN deployment will have a major impact on capacity and coverage. Will only certain groups within the organization have WLAN access, or will it be rolled out across the enterprise? Will you provide guest access to visitors, consultants, and contractors? Most WLANs support just data applications, but many organizations are considering adding voice services. Voice support raises other design considerations that drive the need for denser deployments of access points and different QoS (Quality of Service) settings. • Are there any known major sources of interference? For example, is there a nearby cafeteria with microwave ovens? Commercial-grade microwaves are a particularly bad source of interference. Is there a wireless telephone or video surveillance system not using Wi-Fi? Is there a radar installation nearby? If you cannot find the answer to these questions easily, consider employing a spectrum analysis product, such as the AirMagnet Spectrum Analyzer. • Are building blueprints available? With blueprints, you can see the location of elevators, load-bearing walls, and other building characteristics that can impact signal quality. Different materials, such as concrete walls, brick walls, cubicle walls, glass, and elevator shafts impact signal quality differently. You can often load these blueprints into a planning or site survey tool to make the process easier. • What devices need to access the WLAN? Determine and document the full complement of devices that people will use to access the WLAN. The performance requirements of the WLAN will depend on both the applications and the capabilities of the client devices. For example, design engineers, architects, and doctors tend to work with bandwidth-hungry applications, so you might need to provide greater capacity. Conversely, if it is a warehouse with a low client density of mostly barcode scanners, a lower access point density might be suitable. Finally it is important to consider voice, or the future use of voice. If some or all people will use VoWLAN (Voice over WLAN) devices, that can affect how many users each access point can accommodate. Note: For some access point deployment guidelines, see "Bandwidth Assumptions for Wi-Fi" on page 14. Deployment Guide 11 Chapter 1 Preparing for a WLAN Deployment Site Surveys One of the first questions IT managers ask when they are preparing for a WLAN deployment is whether or not a site survey should be performed. In a site survey, the administrator walks around the facility with a site survey tool to measure the RF (radio frequency) coverage of a test access point or the existing WLAN infrastructure. Whether or not you decide to do a site survey for your enterprise depends on the cost of the survey and the complexity of the environment. The three ways to deploy a wireless network—with and without a site survey—are explained below: • Predeployment Survey The safest approach is to perform a site survey before deployment to determine the best locations for the access points. Typically, site survey professionals temporarily place access points in different locations, take measurements, and adjust their settings and locations as necessary. After they complete the survey, they install the access points, and then perform another site survey to confirm that the goals have been achieved. This method is clearly the most reliable way to deploy a wireless network; however, it can be expensive, time consuming, and impractical if an enterprise has many sites. • Deploy and Check In this scenario, an initial site survey is not performed. Instead, wireless administrators make educated guesses on the best locations for the access points or they use a planning tool to determine the locations more reliably. After deploying the access points, the administrators do a quick site survey. If they need to provide greater coverage, they deploy additional access points. If there are areas where access points are interfering with each other, they then relocate one or more of them. With the Aerohive cooperative RF control, HiveAPs automatically adjust their channel and power to compensate for coverage gaps and areas of interference. The deploy-and-check approach is often much cheaper and faster than doing a predeployment site survey. The risk is that you might have to move some access points and CAT5 (Category 5) Ethernet cables if you do not plan properly. Aerohive provides a huge competitive advantage in the deploy-and-check approach, thanks to its flexible mesh networking capability. An administrator can deploy with mesh (before running wires) and check the performance in several layouts, determine the best layout, and then run the wires to their final location. • Deploy without Survey While it is usually advisable to do a site survey, there are many situations in which it is not feasible or even necessary. If the location is sufficiently small—for example, a deployment of only three or fewer access points—site surveys have limited value because there is virtually no opportunity for interference. If there are numerous remote locations, a site survey might be impractical because of the cost of traveling to each site. In these locations, you can use a slightly denser deployment to ensure appropriate coverage and capacity. With Aerohive Cooperative RF control, HiveAPs automatically adjust their radio power levels to ensure that there is minimal overlap from interfering channels. Usually the cost of extra access points is offset by the cost saved by not doing a site survey in a remote location. 12 Aerohive PLANNING Budgeting Wi-Fi: The Chicken and Egg Problem The hardware cost of a Wi-Fi solution is generally driven by the number of access points needed, and an Aerohive network is no exception. Unfortunately, a traditional challenge of budgeting for Wi-Fi is that it is difficult to know how many access points to plan for until you have deployed and measured them. There are methods of doing site surveys before a deployment to answer these questions. While doing so is often worthwhile, you might just need a general idea of what you would need to budget. Fortunately there are some simple guidelines that you can use to figure out how many access points you need, including the number of access points per square foot, the number of clients per access point, and the distance between access points. • Access Points per Square Foot The simplest and most common way of budgeting access points is per square foot. You simply take the square footage of a building and divide it by some number. The most common metric used today is one access point for every 4,000 to 5,000 square feet for standard offices with cubicles. However, if you need to support voice applications, you need a higher concentration of access points. In this case, the recommended formula is one access point for every 3,000 square feet, or even as low as one access point for every 2,000 square feet. In the lightest weight convenience networks, it is possible to use fewer access points, and densities as low as one access point for every 10,000 to 15,000 square feet can be successful. Keep in mind that such a deployment often has dead spots and can only support very low client densities. • Number of Clients for Each Access Point Another way to determine the number of access points needed is to consider the number of clients you want each access point to support. In a standard office environment, most enterprises plan to support an average of 5 to 15 clients per access point. While the specifications of most access points state that they can support up to about 120 clients, a significantly lower density is recommended to get an acceptable throughput for standard office applications. If you expect to support voice over Wi-Fi in the enterprise, account for those phones as well. With the addition of voice, the client density substantially increases, requiring you to plan for an average of 5 to 10 data clients and 5 to 10 voice clients for each access point. Remember that voice clients consume virtually zero bandwidth when they are not on a call. However, when they are on a call, it is imperative that the traffic goes through. • Distance Between Access Points In a standard office environment, it is a good idea to ensure that access points are between 30 and 100 feet from one another. A distance of 30 feet is needed in high-density environments and those with many walls separating access points. A distance of 100 feet is sufficient in low-density areas with plenty of open space. The three tips above can help determine how many access points to deploy in a given area. In general, the square footage estimate provides the best budgeting estimate, with client estimations and the distance between access points confirming the square footage calculations. As with all rules, there are exceptions. If certain locations in the network have a higher density of clients, such as conference rooms or lecture halls, a higher density of access points is required. Conversely if there are large open areas with few active clients, fewer access points are sufficient. Planning Tools If following general guidelines does not provide enough confidence or if the deployment environment is particularly challenging, you might consider using software planning tools like AirMagnet's Planner software. Such tools are useful in determining the placement of access points without performing a site survey. Deployment Guide 13 Chapter 1 Preparing for a WLAN Deployment Associated Access Point Costs After you determine how many access points you need, it becomes simpler to determine the other costs involved with deploying Wi-Fi because most are driven by the quantity of access points. These costs include the following: • • Installation and Wiring • CAT5 – CAT5 wiring is required for all HiveAPs acting as portals.1 One advantage of Aerohive Networks is that you can deploy HiveAPs in a mesh to avoid some of the wiring costs. • Power – Power lines are required for all HiveAPs acting as mesh points.2 Portals receive power through power lines or through Ethernet cables by using the Power-over-Ethernet (PoE) option. • Installation – HiveAPs can simply snap into standard dropped-ceiling environments. However, if the installation is in a warehouse or any environment without dropped ceilings, consider the installation costs. Infrastructure: PoE Switches You must cable every HiveAP acting as a portal to a switch port. For PoE, there are several considerations: • • 802.3af – The current PoE specification provides enough power for all 802.11a/b/g access points. • 802.3at – The emerging PoE specification supports higher power devices like 802.11n access points. This standard is expected to be ratified at the end of 2008, so products are not yet available. • PoE injectors and midspans – These save money on switch upgrades by injecting power into standard Ethernet connections. Site Survey and Debugging Software • • Professional Services • • For a sizable deployment, you probably will use site survey and debugging software. AirMagnet Laptop Analyzer and Survey are two products that pay for themselves very quickly. These products enable the validation of a deployment and allow you to troubleshoot client and access point issues. (For more information, see the section on "Operational Considerations" on page 18.) When deploying wireless LANs, professional services are often required perform site surveys. Client Software • Depending on the deployment, users can use built-in Microsoft Windows, Linux and/or Macintosh client software (supplicants). • For better services and troubleshooting, consider a third-party supplicant such as Juniper Networks Odyssey Client. Bandwidth Assumptions for Wi-Fi People frequently talk about how much coverage an access point provides; however, it is capacity—not coverage—that typically constrains an access point in an enterprise environment. The challenge is not how far the RF signal can travel (coverage), but how to deliver enough bandwidth to meet the demands of business applications (capacity). In other words, you might be able to cover an office of 50 people with one access point, but if all 50 people choose to access it at the same time, it will certainly become overloaded. Indeed, if you use the formulas provided in this paper, you should find the saturation of access points on your campus to be more than sufficient. Enterprise users are accustomed to speedy switched networks and expect similar performance from their wireless LAN connections. This is why documenting the size and type of applications that will rely on your WLAN is so critical to your planning. In short, if you plan for optimal capacity, complete coverage will follow automatically. 1. A portal is a hive member that links one or more mesh points to the wired LAN. 2. Mesh points are hive members that use a wireless backhaul connection to link through a portal to the wired LAN. 14 Aerohive PLANNING In general, the way to increase capacity is to add more access points (within reason) and tune down the radio power to avoid interference. One reason for deploying a high capacity network is to create a WLAN for voice and data applications. In such a WLAN, everyone has a VoIP handset running wirelessly all the time. In general, the following table shows the standard densities for office deployments. Office Requirements Expected Data Rate Using 802.11g for Each Access Point Access Point Density Coverage (low capacity) 12 Mbps to 24 Mbps 1 access point per 8000 square feet Standard office deployment 36 Mbps 1 access point per 5000 square feet Standard office deployment with voice 54 Mbps 1 access point per 2000 – 3000 square feet Note: Data rate is not the same as TCP throughput. Because of various headers, inter-frame gaps, and session creation, real TCP throughput usually does not exceed 22 Mbps at data rates of 54 Mbps. Overcoming Physical Impediments Not every potential deployment is a standard business campus.The following scenarios are a few that merit special consideration. • Open Space Open spaces, such as a large foyer or an outdoor area, are very easy to cover with Wi-Fi because there are few impediments to propagation and fewer opportunities for multipath interference. In such spaces, Wi-Fi signals can propagate many hundreds of feet. This is good if you want to provide coverage for just a few users. You will run into challenges if there are many users and high capacity service goals. In these situations, it is important to tune down the RF to a minimal level. If you are using Aerohive cooperative RF control, the HiveAPs do this on their own automatically. Another trick is to take advantage of obstacles that block Wi-Fi. Look for trees or walls and put neighboring access points on either side of them. Doing so limits the interference of the two access points and allows for the installation of more access points with less interference. • Warehouse and Retail Warehouse and retail environments present many challenges. One of the largest challenges is that RF characteristics often change because of varying inventory levels and, in the case of retail, seasonal displays (such as tinsel or a stack of soda cans on an end cap). Additionally, metal shelves and high ceilings can be challenges to propagation. To resolve with these issues, it is wise to put at least one access point per aisle to ensure coverage for that aisle. This usually requires a higher density of access points than would otherwise be required. • Configuring Antennas As anyone who has administered a WLAN system in the past knows, proper configuration of the access point antennas at the outset can save you lots of trouble. HiveAPs come standard with fixed omnidirectional antennas. You typically orient these antennas vertically, positioning the antennas on all HiveAPs in the same direction. Omnidirectional antennas create a coverage area that looks like a doughnut, broadcasting to the sides much more effectively than up or down (see Figure 1 on page 16). In general, this is good for most office environments because you have large flat floors. However, it can be a problem in environments with high ceilings. Deployment Guide 15 Chapter 1 Preparing for a WLAN Deployment Figure 1 Omnidirectional Antenna Radiation Pattern The HiveAP can accommodate external antennas via coaxial jacks on its chassis (see "Antennas" on page 28). The jack is a standard male RP-SMA connector. Various patch, directional, and omnidirectional antennas can be used to change the coverage pattern. The most common external antennas are patch antennas. These are directional antennas that provide coverage in a single direction. Most commonly they have a transmission pattern as shown in Figure 2. Based on the gain, the signal will be wide (like the low gain antenna shown on top) or narrow and long (like the high gain antenna shown on the bottom). Note that the coverage patterns are not perfect for these antennas and that they often broadcast slightly in other directions than the primary one. These extra "lobes" can be seen in both of the patterns shown below. Figure 2 Directional Antenna Patterns (Bird’s Eye View) Patch Antennas Lower Gain Higher Gain The following are some quick hints for deploying access points: • Standard sheetrock walls and dropped ceilings are the best locations for mounting access points. • When deploying WLANs in retail stores, doing a site survey at each store is likely to be impractical. It is more common to run detailed site surveys at a few locations and use the results to set up deployment guidelines for the remaining sites. • Be aware of metal-lined firewalls, steel pillars, and other metallic surfaces. RF signals can reflect off metal surfaces, which can cause unexpected coverage patterns. Also watch out for objects that can block or reflect signals, such as mirrors, plants, walls, steel doors, elevator shafts, and bathroom stalls. 16 Aerohive PLANNING • The quality and performance of a Wi-Fi network is a function of the signal-to-noise ratio. To avoid noise issues, check the area for common noise generators such as industrial microwave ovens, wireless video cameras, cordless phones and headsets, and Bluetooth devices. Such devices especially cause interference in the 2.4 GHz spectrum. • Plan appropriately for high ceilings. With an omnidirectional antenna, the downward coverage is not great. In normal office space, the ceilings rarely exceed 15 feet, so this issue does not come up very often. In environments such as warehouses, where ceilings can be up to 50 feet high, ceiling-mounted access points are not optimal. It is best to deploy them on non-metallic walls about 10 feet to 15 feet above the floor. If this is not feasible, using patch antennas can help direct the RF energy downward. • In high-density or high-capacity environments, placing access points on exterior walls allows for a greater number of cells inside the building and more capacity. In other deployments, it is recommended that the outer access points be no farther than 30 feet from the exterior walls to ensure coverage. Preparing the Wired Network for Wireless One of the advantages of moving to an Aerohive WLAN is that you do not have to make changes to the underlying network, such as putting controllers into wiring closets. This can save you considerable time and effort during installation. However, some network changes might make sense for some deployments. For example, you might want to add additional VLANs or security settings. This section covers a few of the more common considerations that IT departments are handling. • 802.1Q VLANs HiveAPs can segment users into VLANs if an administrator wants. This decision can be made by a returned RADIUS attribute or it can be configured as part of a user profile or SSID. Enterprises often set up separate VLANs for wireless and guest access, so that this traffic is segmented from the rest of the network; however, it is possible to set up any number of other VLANs for further segmentation. (For an example, see "Example 9: Creating WLAN Policies" on page 126.) • Firewalls Depending on the environment, enterprises might use firewalls to segment wired and wireless data. This can be implemented as a discrete firewall enforcing traffic between VLANs or between ports, or you might use the stateful firewall that is integrated in HiveOS (the HiveAP operating system). • RADIUS Authentication If RADIUS authentication is required, then a RADIUS server must be in place and be able to support the necessary protocols for wireless—often called 802.1X EAP types: PEAP, EAP-TLS, EAP-TTLS, WEP 8021.x (dynamic WEP), LEAP, EAP-FAST, and captive web portal authentication using CHAP. • DNS and DHCP Configuration If you use the Aerohive HiveManager (see the section on "Operational Considerations" on page 18), it is possible to install HiveAPs without any extra configuration and they will be able to contact HiveManager for management. If the HiveAPs are linked to a different subnet than the one to which HiveManager is connected, then you can set either a DHCP option or DNS entry to give the location of HiveManager (see "How HiveAPs Connect to HiveManager" on page 95). Deployment Guide 17 Chapter 1 Preparing for a WLAN Deployment OPERATIONAL CONSIDERATIONS To make your WLAN deployment process as smooth as possible, you should consider more than just the distribution and installation of access points. You should also consider how you will manage, optimize, and troubleshoot your WLAN after deployment. Tuning Approach building an enterprise WLAN with the same life-cycle approach you would apply to a wired network. After you deploy the WLAN, revisit key network engineering processes to account for changes in the environment. Watch for access points that are overloaded or are under utilized, and check for potential dead spots. Furthermore, be aware that the likely points of failure can change as the environment changes. For example, a neighboring business might install access points that cause RF interference on your network. You should schedule and perform periodic walkthroughs to ensure that the design goals of the wireless network continue to be met. The Aerohive HiveManager provides quick views into how the network is behaving, which HiveAPs are the most heavily loaded, and which have the most clients. Troubleshooting Some of the most common issues that arise after deploying a new wireless network are RF interference, RADIUS issues, and desktop client issues. The first step in troubleshooting is to look at logs and use debug commands. Aerohive offers an extensive set of event monitoring and debug tools that you can use through HiveManager, the Aerohive network management system. For additional troubleshooting, particularly of clients or neighboring networks, Aerohive recommends two tools: Ethereal Warehouser (http://www.wireshark.org/) and AirMagnet Laptop Analyzer (http://www.airmagnet.com/products/laptop.htm). Management Current Wi-Fi networks typically span an entire company and have complex security policies. Fortunately, the HiveManager Network Management System makes it simple to manage large networks from a central location. It provides a single centralized management instance for the entire wireless network. While managed HiveAPs can operate without HiveManager, it simplifies the provisioning of global policy management and centralized configuration and monitoring. HiveManager lowers operating costs by speeding deployment, configuration, and monitoring of the wireless network. Managing faults and alarms is critical to maintaining uptime. You can view and manage events through HiveManager logging. Optionally, you can use a third-party tool such as HP OpenView. HiveManager makes it easy to monitor and troubleshoot HiveAPs within a WLAN infrastructure. HiveManager can import hierarchical map views that represent the physical location of the network, from the perspective of the entire world down to the floor level. Deploying with Confidence Moving a large enterprise—or even a small one—to a WLAN for the very first time need not be daunting. If you have moderate experience with LAN deployments of other types and you have taken time to get answers to the important questions that will affect the network data load, you have every prerequisite for success. The bottom line is to remember to take stock of your project before you begin to ward against unforeseen costs and performance bottlenecks. If you have considered the issues and guidelines presented here, you are not far away from a successful Aerohive WLAN deployment. 18 Aerohive BASIC WI-FI CONCEPTS BASIC WI-FI CONCEPTS The goal of this section is to provide some background on Wi-Fi propagation and how to lay out a wireless network. While RF (radio frequency) engineering is a rather complicated science, this section provides a simple overview on the basics of Wi-Fi propagation and channel layout that you need to be able to install an enterprise WLAN. The first thing to know is that Wi-Fi is forgiving. Wi-Fi tends to transmit a bit farther than you expect, and even in cases of interference, it tends to just work. This can be both a blessing and a curse. It is a blessing because people will likely have access to the network, and it is a curse because your overall performance might be suboptimal without obvious symptoms, like lack of connectivity. Understanding the basics presented in this section will help ensure a high performance layout. The first concept to understand is signal strength and how it relates to throughput. Radio power is measured in dBm (decibels relative to one milliwatt) where 0 dBm = 1 milliwatt, but decibels increase using a log10 math function. Rather than dusting off your old math books and pulling out your calculator, look at the dBm-to-milliwatt converter that appears below. Often in Wi-Fi, dBm and milliwatts (mW)—and microwatts (μW)—are used interchangeably. The following table converts between the two units of measurement. dBm-to-milliwatt 20 dBm = 100 mW 2 dBm = 1.6 mW 15 dBm = 32 mW 1 dBm = 1.3 mW 10 dBm = 10 mW 0 dBm = 1.0 mW 5 dBm = 3.2 mW -1 dBm = 794 µW 4 dBm = 2.5 mW -5 dBm = 316 µW 3 dBm = 2.0 mW -10 dBm = 100 µW In RF, there is also a relative measurement that you can use to compare two numbers. This measurement is simply dB (without the "m"). To see how this concept is applied, consider how radio signal propagation changes over a distance and how it can be affected. Figure 3 on page 20 shows signal strength over distance as a curve that has the best signal strength closer to the access point. It also shows noise. In general, noise is considered to be low-level background RF signals that can interfere with a WLAN. This noise tends to be the garbled background RF that comes from everything from the sun and stars to man-made interfering devices like Bluetooth headsets. It is impossible to block out noise and it should not be attempted. This low level of background noise is called the "noise floor". Deployment Guide 19 Chapter 1 Preparing for a WLAN Deployment Figure 3 Path Loss in an Open Space Received Signal Signal-to-Noise Ratio Noise Distance When clients send a packet, the ratio of the signal-to-noise (SNR) level defines the quality of the link, which is directly related to the performance of the network. Based on the SNR, the client and AP negotiate a data rate in which to send the packet, so the higher the SNR the better. For good performance, the SNR should be greater than 20 dB, and for optimal performance it should be at least 25 dB. Signal strength not only diminishes over distance but it can also be affected by objects in the way (see Figure 4). This can be a wall, a tree, or even a person. There is a fairly predictable dB drop through most objects that also decreases the SNR, thus decreasing the data rate. While this appears to be a bad thing, clever Wi-Fi installers use it to their advantage. It allows them to place more access points in a tighter spot by using pre-existing walls and other impediments to Wi-Fi propagation to keep them from interfering with each other. Figure 4 Path Loss through a Wall Received Signal Wall Signal-to-Noise Ratio Noise Distance 20 Aerohive BASIC WI-FI CONCEPTS Microwave ovens, wireless video cameras, Bluetooth headsets, and cordless phones can all interfere with Wi-Fi signals (see Figure 5). Excess noise in an environment is often difficult to diagnose and can have a major negative impact on network performance. To discover noise sources, a spectrum analysis system is needed. AirMagnet provides an affordable spectrum analysis tool that operates in the 2.4 GHz and 5 GHz spectra. Figure 5 Path Loss with Noise (from Microwave) Received Signal Signal-to-Noise Ratio Noise Distance Now that you have a sense of how Wi-Fi performance changes over distance and with noise, look at some ways to perform channel assignment. If two access points are on the same channel right next to each other, they are forced to share the same spectrum. This means that they share the 54 Mbps available in 802.11a/g rather than each being capable of 54-Mbps speeds independently. This essentially halves the bandwidth for each access point. To manage this situation, make sure that neighboring APs are on different channels and that their power is adjusted so that it does not overlap that of other APs with the same channel. In the 2.4 GHz spectrum, there are 11 channels in the United States. However, a Wi-Fi signal consumes more than one channel. Consequently, there are only 3 non-overlapping channels: 1, 6, and 11. To achieve optimal performance, you need to design a channel layout pattern such as the one on the left in Figure 6. Figure 6 Channel Layout Patterns 7-to-1 Layout Pattern 3-to-1 Layout Pattern 36 52 11 11 11 36 52 60 64 40 11 11 11 11 11 11 11 60 64 40 44 56 36 52 44 56 36 52 60 64 40 36 52 60 64 40 44 56 60 64 40 44 56 36 52 44 56 36 52 60 64 40 60 64 40 44 56 44 56 Deployment Guide 21
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