Home | Skip to Content | Skip to Search | Skip to Navigation | Skip to Footer |
Worldwide [change] |Register |About Cisco
Guest

Hierarchical Navigation

Cisco 4400 Series Wireless LAN Controllers

Quick Start Design and Implementation Guide for Cisco Wireless IP Phone 7920 with the Unified Wireless Network

Downloads

Table Of Contents

Quick Start Design and Implementation Guide
for Cisco Wireless IP Phone 7920 with the Unified Wireless Network

Contents

Preface

Audience

Purpose

Introduction

Overview of the Cisco Unified Wireless Network

Caveats

Cisco Wireless IP Phone 7920 Firmware 2.0 and Above

Cisco Wireless LAN Controller 3.0

Cisco Wireless LAN Controller 3.1

Cisco Wireless LAN Controller 3.2, 4.0, and 4.1

AP1000 Series Access Points

Load Balancing

Components of the Cisco Unified Wireless Network

Cisco Wireless LAN Controllers

Cisco Lightweight Access Points

Cisco Antennas and Accessories

Lightweight Access Point Protocol (LWAPP)

Quality of Service (QoS)

Configuring the Cisco Wireless LAN Controller

WLANs Menu

Creating Wireless LANs

Editing a Wireless LAN

Configuration Examples

Controller Menu

Creating VLAN Interfaces

Editing a VLAN Interface

Configuring Mobility Management

Configuring RF Domains

Configuring QoS Profiles

Wireless Menu

Sample Coverage Map Generated by the Cisco Wireless Control System

Required Commands

Disabling 802.11 Aggressive Load Balancing

Enabling 802.11 Phone Support (QBSS)

Additional Show Commands

Viewing the Details of a Cisco Wireless IP Phone 7920


Quick Start Design and Implementation Guide
for Cisco Wireless IP Phone 7920 with the Unified Wireless Network

Contents

This document contains the following sections:

•Preface

•Introduction

•Overview of the Cisco Unified Wireless Network

•Components of the Cisco Unified Wireless Network

•Configuring the Cisco Wireless LAN Controller

•Sample Coverage Map Generated by the Cisco Wireless Control System

•Required Commands

•Additional Show Commands

•Viewing the Details of a Cisco Wireless IP Phone 7920

Preface

This document discusses the design and implementation of the Cisco unified wireless network using lightweight access points and the Cisco Wireless IP Phone 7920. It does not address implementation with autonomous access points.

Note This document does not cover radio frequency (RF) coverage designs for the Cisco Wireless IP Phone 7920. RF coverage considerations for this phone are the same as for all access point types. Any functional differences between the Cisco autonomous and lightweight access points with respect to a Cisco Wireless IP Phone 7920 deployment are noted in this document. For more information on RF coverage, see the Cisco Wireless IP Phone 7920 Design and Deployment Guide at: http://www.cisco.com/go/srnd

Most of the configuration parameters on the wireless LAN controller that are required to support the Cisco Wireless IP Phone 7920 are accessible from the graphical user interface (GUI). However, some commands must be entered through the command line interface (CLI). This guide provides the required commands and screens of the required GUI parameters.

Audience

This document is intended primarily for system engineers, partners, and customers who are responsible for designing, implementing, and configuring wireless network solutions with Cisco wireless LAN controllers.

Purpose

This document provides configuration recommendations for implementing a wireless LAN IP phone network with Cisco wireless LAN controllers. It includes configuration examples for Quality of Service (QoS).

This version of the document includes configurations for Cisco Unified Wireless Network controller versions 3.0, 3.1, and 3.2. However, Cisco recommends that the 3.2 release be used in all networks. The Release Notes for 3.2.78 can be found on www.cisco.com.

The major enhancements of this release that improve voice performance are QoS Basis Service Set (QBSS) support for the Cisco Wireless IP Phone 7920 and the addition of the QoS packet marking on LWAPP packets, which is representative of the marking of the packet prior to encapsulation.

The Cisco Unified Wireless Network provides automatic configuration of an access point's radio channel and radio transmit power. This automated configuration is the recommended means of access point radio channel and radio power configuration for the Cisco Wireless IP Phone 7920 running code version 2.01.

Because users on active phone calls expect complete coverage throughout a facility, Cisco recommends that the above-mentioned Wireless IP Phone 7920 Design and Deployment Guide be studied for ideas on the number of access points that a site may require, antenna types, and other considerations.

Introduction

The Cisco unified wireless network is delivered by lightweight access points, wireless LAN controllers, and the Wireless Control System (WCS) management application. This network represents the most comprehensive set of capabilities in the industry, including integrated guest access, wireless intrusion detection, scalable Layer 3 mobility, and location services. Most Cisco Aironet access points are available in versions designed for lightweight operation.

Overview of the Cisco Unified Wireless Network

Cisco wireless LAN controllers provide the framework to integrate and extend wireless connectivity to wireless LAN clients for a variety of applications. This document pertains to the Cisco Wireless IP Phone 7920. It focuses on configuring the Cisco wireless LAN controllers to provide quality voice communications with the Cisco Wireless IP Phone 7920. For authentication configurations, see the Cisco Wireless LAN Controller Configuration Guide at: http://www.cisco.com/en/US/products/hw/wireless/tsd_products_support_category_home.html

These Cisco products support the Cisco Wireless IP Phone 7920:

•Cisco lightweight access points supporting the Lightweight Access Point Protocol (LWAPP)

•Cisco wireless LAN controller versions 3.0, 3.1, 3.2, 4.0, and 4.1

•Cisco distribution and access switches

•Cisco Secure Access Control Server (ACS) or equivalent (3.1 minimum)

•Cisco CallManager [3.3(3)SR1 minimum]

•Cisco Wireless IP Phone 7920 firmware 1.09 or higher (3.0 recommended)

•PC-based Cisco Wireless IP Phone 7920 Configuration Utility

•VLANs for voice, data, and management

Caveats

Cisco Wireless IP Phone 7920 Firmware 2.0 and Above

The following information pertains to Cisco Wireless IP Phone 7920 firmware 2.0 and 2.01:

•TKIP and WPA are supported.

•AES, WPA2, WMM, and proactive key cache (PKC) are not supported.

•WEP128 in the Cisco Wireless IP Phone 7920 matches WEP104 on the controllers.

•All 7920 firmware versions later than 1.8 use AP CAC. All 7921 firmware versions use load-based CAC. If 7920s and 7921s are using the same dynamic interface, make sure both CACs are configured on that interface.

Cisco Wireless LAN Controller 3.0

The following information pertains to Cisco wireless LAN controller 3.0:

•Controller version 3.0 has version 1 of QBSS, which supports Call Control Access.

•Cisco recommends enabling QBSS.

•Dynamic transmit power control (DTPC), through which the access point tells the Cisco Wireless IP Phone 7920 the transmit power to use, is not supported.

Note If the Cisco Wireless IP Phone 7920 must have a static transmit power setting (default =
20 mW), Cisco recommends that the static transmit power of the 7920 match the transmit power of the access points.

•Cisco Centralized Key Management (CCKM) and fast secure roaming are not supported. WEP and WPA pre-shared key are supported.

•If the controller is tagging packets, the Cisco switches require the native VLAN to be VLAN 1.

•Aggressive load balancing must be disabled.

•These commands must be entered to support the Cisco Wireless IP Phone 7920:

–dot11-phone compat (the QBSS command)

–load-balancing status disable (the aggressive load balance command)

Note Aggressive load balancing can also be disabled through the GUI.

Note The complete syntax of each command is shown in the "Required Commands" section.

Cisco Wireless LAN Controller 3.1

The following information pertains to Cisco wireless LAN controller 3.1:

•Cisco recommends using the AP CAC Limit field. However, the AP CAC Limit field does not correctly advertise the QBSS value. This will be corrected in the next release.

•Cisco recommends enabling QBSS.

•Dynamic transmit power control (DTPC) is supported and is on by default. The 7920 learns the transmit power of the access point and then adjusts its transmit power to match.

•Cisco Centralized Key Management (CCKM) and fast secure roaming are not supported. WEP and WPA pre-shared key are supported.

•If the controller is tagging packets, the Cisco switches require the native VLAN to be VLAN 1.

•Aggressive load balancing must be disabled.

Cisco Wireless LAN Controller 3.2, 4.0, and 4.1

The following information pertains to Cisco wireless LAN controller 3.2:

•Cisco recommends using the AP CAC Limit field.

•Cisco recommends enabling QBSS.

•Dynamic transmit power control (DTPC) is supported and is on by default. The 7920 learns the transmit power of the access point and then adjusts its transmit power to match.

•Cisco Centralized Key Management (CCKM) and fast secure roaming are not supported. WEP and WPA pre-shared key are supported.

•If the controller is tagging packets, the Cisco switches require the native VLAN to be VLAN 1.

•Aggressive load balancing must be disabled.

•If WMM is required in the voice VLAN for voice clients other than the Cisco Wireless IP Phone 7920, then the WMM setting must be set to Allowed.

AP1000 Series Access Points

The following information pertains to AP1000 series access points:

•The AP1000 does not support Cisco power over Ethernet (PoE).

•The AP1000 supports only a select number of Aironet antennas. See Table 1 for a list of supported antennas.

Load Balancing

The Cisco Wireless IP Phone 7920 has its own method of determining when to load balance. Having Aggressive Load Balancing enabled creates unneeded delays that could lead to noticeable jitter and may also cause authentication failures and association flapping. Data clients do not have their own roaming algorithms and would benefit from having load balancing enabled.

Components of the Cisco Unified Wireless Network

Cisco wireless LAN controllers provide lightweight access point configuration through security policies, QoS policies, RF management, and mobility management. These software features enhance wireless LAN client mobility and simplify wireless LAN deployment and management. See Figure 1 for an overview.

This section describes the following components:

•Cisco wireless LAN controllers

•Cisco lightweight access points

•Cisco antennas and accessories

•Lightweight Access Point Protocol (LWAPP)

Figure 1 Overview of the Cisco Unified Wireless Network

Cisco Wireless LAN Controllers

Figure 2 shows and describes the Cisco wireless LAN controllers.

Figure 2 Cisco Wireless LAN Controllers

For more information on the Cisco wireless LAN controllers, see the controller documentation at: http://www.cisco.com/en/US/products/hw/wireless/tsd_products_support_category_home.html

Cisco Lightweight Access Points

Cisco lightweight access points receive their configurations from the wireless LAN controller after their X.509 certificate has been authenticated at the controller. Figure 3 shows and describes the Cisco lightweight access points.

Figure 3 Cisco Lightweight Access Points

The Cisco Aironet 1000, 1130AG, 1230AG, and 1240AG series access points are available in a lightweight mode, and the Cisco Aironet 1130AG, 1230AG, and 1240AG series access points can be field upgraded from Cisco IOS software to lightweight operation.

Cisco Antennas and Accessories

Cisco Aironet access points with external connectors and Cisco antennas and accessories use RP-TNC connectors. Cisco antennas and cables can be used with previous Airespace installations and new installations, with the exception that no antenna has a gain of 7 dBi or higher. The FCC approvals in place for the AP1000 include only antennas with less than 7 dBi of gain. Table 1 provides a list of approved antennas.

Table 1 Cisco Approved Antennas for the AP1020 and AP1030

Part Number
Description

AIR-ANT1728

2.4-GHz 5.2-dBi omnidirectional

AIR-ANT1729

2.4-GHz 6.0-dBi patch

AIR-ANT2012

2.4-GHz 6.5-dBi diversity patch

AIR-ANT3213

2.4-GHz 5.2-dBi diversity omnidirectional

AIR-ANT4941

2.4-GHz 2.2-dBi dipole

AIR-ANT5135D-R

5-GHz 3.5-dBi omnidirectional

AIR-ANT5160V-R

5-GHz 6.0-dBi omnidirectional

AIR-ANT5959

2.4-GHz 2.0-dBi diversity omnidirectional


Note For 1230AG and 1240AG series access points, see the Cisco Aironet Antenna Reference Guide at: http://www.cisco.com/en/US/products/hw/wireless/ps469/index.html

Lightweight Access Point Protocol (LWAPP)

LWAPP is a tunnel protocol that is used to pass all traffic between the controllers and the access points. Figure 4 shows how LWAPP is used within a Cisco wireless LAN.

Figure 4 The Role of LWAPP in a Cisco Wireless LAN

For Layer 2, LWAPP uses packets in an Ethernet frame (Ethertype 0xBBBB). The Cisco wireless LAN controller and access point must be connected to the same VLAN/subnet.

For Layer 3, LWAPP uses packets in a UDP/IP frame. LWAPP control traffic uses source port 1024 or greater and destination port 12223, and LWAPP data traffic uses source port 1024 or greater and destination port 12222. The Cisco wireless LAN controller and access point can be connected to the same VLAN/subnet or to a different VLAN/subnet.

All VoIP Skinny Client Control Protocol (SCCP) and data traffic is encapsulated by LWAPP. It is therefore a requirement that access control lists (ACLs), firewalls, and network address translations (NATs) do not block ports 12222 and 12223.

Quality of Service (QoS)

All wireless LAN traffic that passes between the access point and the wireless LAN controller is encapsulated using LWAPP. While LWAPP encapsulation maintains the Layer 3 marking in the original packet, this marking is not copied onto the header of the LWAPP packet such that QoS mechanisms in the network infrastructure can classify and queue based on the original Layer 3 marking. See the Cisco Wireless LAN Controller Configuration Guide at:

http://www.cisco.com/en/US/products/hw/wireless/tsd_products_support_category_home.html

Once the LWAPP packet is de-encapsulated at the access point or wireless LAN controller, the original Layer 3 marking is again used by QoS mechanisms in the network infrastructure. Packets traveling downstream from the wireless LAN controller to the access point are capable of maintaining the original packet's Layer 2 class of service (CoS) marking. Provided the network infrastructure provides differentiated services code point (DSCP)-to-CoS mappings and the DSCP and CoS markings are trusted, voice media and voice-signaling packets traveling toward the access point should be marked with a CoS of 5 and CoS of 3 respectively.

Some Cisco end points, including the Cisco Wireless IP Phone 7920, mark voice-signaling packets as DSCP 26 (or PHB AF31). However, the new marking recommendation is to use DSCP 24 (or PHB CS3). Until all end-point devices and call control applications adopt the new marking strategy for voice-signaling packets, QoS configuration should continue to provide the same treatment for both markings.

Figure 5 illustrates the packet flow from the Cisco CallManager to the Cisco Wireless IP Phone 7920, and Figure 6 illustrates the packet flow in the opposite direction (from the Cisco Wireless IP Phone 7920 to the Cisco CallManager).

Figure 5 Packet Flow to the Cisco Wireless IP Phone 7920

1. The Cisco CallManager directs IP phones to mark voice media traffic or RTP traffic with DSCP 46 (or PHB EF) and voice-signaling traffic (SCCP) with DSCP 24 (or PHB CS3).

2-3. QoS policy on the network should trust voice media and signaling packet markings based on configured trust boundaries.

4. Layer 3 DSCP markings should be mapped to Layer 2 CoS markings on the switch to which the wireless LAN controller is attached.

5. In code versions prior to 3.2.78, LWAPP packets are marked with 0x00 for best effort.

6. The lightweight access point marks the over-the-air packets to the Cisco Wireless IP Phone 7920 with a DSCP value of 0x2e.

Figure 6 Packet Flow from the Cisco Wireless IP Phone 7920

1. The Cisco Wireless IP Phone 7920 marks the over-the-air packets with a DSCP value of 0x2e.

2. The lightweight access point encapsulates the RTP packet and then sends it to the access switch.

3. The access switch's port passes the encapsulated packet to the controller.

4. The controller passes the unencapsulated RTP packet back to the access switch with the original markings.

5-6. QoS policy on the network should trust voice media and signaling packet markings based on configured trust boundaries.

Note All other traffic on the wireless network should be marked as "best effort" or with some intermediate classification as outlined in the Enterprise Quality of Service SRND located at:
http://www.cisco.com/go/srnd

Note Cisco recommends that Port Fast be set on the switch ports to which access points are connected.

Configuring the Cisco Wireless LAN Controller

This section explains how to configure the Cisco wireless LAN controller using the WLANs, Controller, and Wireless menus.

Note This document does not include configuration information for the controller's Monitor, Security, Management, and Commands menus. See the Cisco online documentation for information on these menus and their parameters.

WLANs Menu

Follow the instructions in this section to create and edit wireless LANs.

Creating Wireless LANs

Follow these steps to create wireless LANs on the controller based on SSIDs for the lightweight access point.

Step 1 Click WLANs on the menu bar to access the WLANs window (see Figure 7).

Figure 7 WLANs Window

Step 2 Click New to create a wireless LAN.

Note Click Help for additional information on any data field.

Step 3 Configure the properties of the wireless LAN and save your settings.

Editing a Wireless LAN

Follow these steps to edit an existing wireless LAN on the controller.

Step 1 On the WLANs window, click Edit for the wireless LAN that you want to modify. The WLANs > Edit window appears (see Figure 8).

Figure 8 WLANs > Edit Window

Step 2 Modify the parameters as desired and click Apply. See the next section for configuration examples.

Configuration Examples

This section provides configuration examples for creating wireless LANs on the controller.

In Figure 8, the data SSID (TME-AIRE) and data VLAN are set to a Quality of Service (QoS) value of Silver, which is equivalent to the 802.11e and WiFi WMM EDCA access category of Best Effort.

Note On the controller, the QoS priority order is Platinum, Gold, Silver, and Bronze. The equivalent priority order for the 802.11e access category is Voice (802.1d tags of 7&6), Video (802.1d tags of 5&4), Best Effort (802.1d tags of 3&0), and Background (802.1d tags of 2&1).

Configuration Example 1 - Voice SSID

Cisco recommends that the controller be set with a separate SSID/VLAN for Cisco Wireless IP Phone 7920 voice traffic and that the Quality of Service (QoS) field be set to Platinum (voice). Figure 9 provides a voice SSID configuration example.

This configuration example does not include encryption or authentication. Cisco recommends that this configuration be used when a VoIP network is first created so that the connections can be verified before security is added.

In version 3.1, the 802.11e Policy field has been replaced with the 7920 Phone Support field. Two check boxes are available for this new field. In version 3.0, leave WME Policy and 802.11e Policy at their default values. In versions 3.1 and 3.2, check the AP CAC Limit check box.

The DHCP Server field is set to Override as the Cisco Wireless IP Phone 7920 clients are likely to need the same IP address range as wired VoIP clients.

Figure 9 Voice SSID Example

Configuration Example 2 - Data SSID

Cisco also recommends that the controller be set with a separate SSID/VLAN for data traffic and that the QoS field be set to Silver (best effort). Figure 10 provides a data SSID configuration example.

Figure 10 Data SSID Example

Configuration Example 3 - Guest SSID

Figure 11 provides a guest SSID configuration example. In this example, the Guest SSID has a QoS value of Bronze (background), the lowest priority.

Figure 11 Guest SSID Example

Controller Menu

Follow the instructions in this section to create and edit VLAN interfaces.

Note The VLAN identifications assigned in this section are for example only. They need to match those of the overall network design.

Creating VLAN Interfaces

Follow these steps to create VLAN interfaces.

Step 1 Click Controller on the menu bar to access the General window (see Figure 12).

Figure 12 General Window

Step 2 Change the Aggressive Load Balancing field from the default value of Enabled to Disabled.

Note The LWAPP Transport Mode is set to Layer 3.

Step 3 Click Interfaces.

Step 4 When the Interfaces window appears (see Figure 13), click New.

Figure 13 Interfaces Window

In Figure 13, the "management" interface has a VLAN identifier of 90, which ties it to the infrastructure management VLAN. The "service-port" interface is on the default VLAN of 1, which is used for data.

Step 5 Save your settings.

Editing a VLAN Interface

Follow these steps to edit an existing VLAN interface.

Step 1 On the Interfaces window, click Edit for the VLAN interface that you want to modify. For example, to set parameters for the "voice" interface in Figure 13, click Edit in the fifth row. The Interfaces > Edit window appears (see Figure 14).

Figure 14 Interfaces > Edit Window

In Figure 14, the "voice" interface is on VLAN 30. In this example, the wired VLAN for VoIP and the VLAN for VoIP on the wireless LAN are 30. The wireless LAN SSID for VoIP is voice.

Step 2 Set the VLAN identifier to match the voice VLAN on the wired infrastructure.

Step 3 Enter the IP address, netmask, and gateway IP address. These are mandatory fields.

Step 4 Enter the port number, which is the physical port number of the VLAN. This port connects to a trunk port on the distribution switch.

Step 5 Enter the primary and secondary DHCP server addresses. These fields specify the DHCP servers that provide dynamic IP addresses to the Cisco Wireless IP Phone 7920 clients. These servers could be internal DHCP servers or external servers. It is likely that the Primary DHCP Server address will be the same as that for the wired VoIP clients.

Configuring Mobility Management

A wireless LAN data client or a voice-over-wireless-LAN voice client must be able to maintain its association seamlessly from one access point to another securely and with as little latency as possible. A mobility group provides the mechanism for pooling resources together to facilitate this desired client behavior. A mobility group does more than just define the RF connectivity of the client. It defines the infrastructure resources and their connectivity to each other. If a voice-over-wireless-LAN client needs to seamlessly roam from one location to another, then the resources in those locations need to be in the same defined mobility group.

Note Clients do not roam across mobility groups.

This section covers basic configurations for the three levels of network complexity. Figure 15 through Figure 17 illustrate these levels. They use a tag name of WLC (wireless LAN controller), which is the reference for the switch or blade controller.

When a wireless client associates and authenticates to an access point, the access point's controller places an entry for that client in its client database. This entry includes the client's MAC and IP addresses, security context and associations, quality of service (QoS) contexts, the WLAN, and the associated access point. Figure 15 shows a wireless client roaming from one access point to another when both access points are joined to the same controller.

Figure 15 Intra-Controller Roaming

When the wireless client moves its association from one access point to another, the controller simply updates the client database with the newly associated access point. If necessary, new security context and associations are established as well.

Layer 2 roaming occurs when a client roams from an access point joined to one controller to an access point joined to a different controller (see Figure 16).

Figure 16 Layer 2 Inter-Controller Roaming

A Layer 2 roam occurs when the controllers' wireless LAN interfaces are on the same IP subnet. When the client associates to an access point joined to a new controller, the new controller exchanges mobility messages with the original controller, and the client database entry is moved to the new controller. New security context and associations are established if necessary, and the client database entry is updated for the new access point. This process is transparent to the user.

Figure 17 illustrates an inter-controller roam at Layer 3.

Figure 17 Layer 3 Inter-Controller Roaming

A Layer 3 roam occurs when the controllers' wireless LAN interfaces are on different IP subnets. The inter-controller roaming is similar to Layer 2 roaming in that the controllers exchange mobility messages on the client roam. However, instead of moving the client database entry to the new controller, the original controller marks the client with an "Anchor" entry in its own client database. The database entry is copied to the new controller client database and marked with a "Foreign" entry in the new controller. The roam remains transparent to the wireless client, and the client maintains its original IP address.

After a Layer 3 roam, data to and from the wireless client flows in an asymmetric traffic path. Traffic from the client to the network is forwarded directly into the network by the foreign controller.

Note Both Layer 2 and Layer 3 inter-controller roaming require the controllers to be in the same mobility group. See the next two sections for a description of mobility groups and instructions for configuring them.

Overview of Mobility Groups

A set of controllers can be configured as a mobility group. By creating a mobility group, you can enable multiple controllers in a network to dynamically share information and forward data traffic when inter-controller roaming occurs. Controllers can share the context and state of client devices and controller loading information. With this information, the network can support inter-controller wireless LAN roaming, access point load balancing, and controller redundancy.

The basic requirements for controllers in a mobility group are:

•IP connectivity must exist between the management interfaces of all controllers.

Note You can verify IP connectivity by pinging the controllers.

•All controllers must be configured with the same mobility group name.

Note The mobility group name is generally set at deployment time through the controller setup script. However, you can change it if necessary through the Default Mobility Domain Name field on the Controller > General page (see Figure 18). The mobility group name is case sensitive.

Figure 18 Mobility Group Name

• All controllers must be configured with the same virtual interface IP address.

•You must have gathered the MAC address and IP address of every controller that is to be included in the mobility group. This information is necessary because you will be configuring all controllers with the MAC address and IP address of all the other mobility group members.

Note You can find the MAC and IP addresses of the other controllers to be included in the mobility group on the Controller > Mobility Groups page of each controller's GUI.

Using the Controller GUI to Configure Mobility Groups

Follow these steps to add mobility group members using the controller GUI.

Note Mobility groups can also be configured through the Wireless Control System (WCS), the software that manages Cisco wireless LAN controllers. WCS is the recommended option.

Step 1 Click Controller > Mobility Groups to access the Static Mobility Group Members page (see Figure 19).

Figure 19 Static Mobility Group Members Page

This page shows the mobility group name in the Default Mobility Group field and lists the MAC address and IP address of each controller that is currently a member of the mobility group.

Note Remember that each controller member of a mobility group must have the same mobility group name configured.

Step 2 Click New to access the Mobility Group Member > New page (see Figure 20).

Figure 20 Mobility Group Member > New Page

Follow these steps to add a controller to the mobility group:

a. In the Member IP Address field, enter the management interface IP address of the controller to be added.

b. In the Member MAC Address field, enter the MAC address of the controller to be added.

c. In the Group Name field, enter the name of the mobility group.

d. Click Apply to save your changes.

e. Repeat Step a through Step d to add all of the controllers in the mobility group.

Note As an alternative to Step 2, you can bulk add members by selecting Edit All on the Static Mobility Group Members page (see Figure 19). The Mobility Group Members > Edit All page appears (see Figure 21).

Figure 21 Mobility Group Members > Edit All Page

Step 3 Repeat this procedure on every controller to be included in the mobility group.

Configuring RF Domains

An RF domain, also known as an RF group, is another critical deployment concept. An RF domain is a cluster of controllers that coordinate their dynamic radio resource management (RRM) calculations on a per 802.11 PHY type. An RF domain exists for each 802.11 PHY type. Clustering controllers into RF domains enables the dynamic RRM algorithms to scale beyond a single controller and span building floors, buildings, and even campuses. RRM parameters and timers can be adjusted to extend the "dynamics" of data gathering.

Lightweight access points periodically send out neighbor messages over the air that include the controller IP address and a hashed message integrity check (MIC) from the timestamp and BSSID of the access point. The hashing algorithm uses a shared secret that is configured on the controller and pushed out to each access point. Access points sharing the same secret are able to validate messages from each other via the MIC. When access points on different controllers hear validated neighbor messages at a signal strength of -80 dBm or stronger, the controllers dynamically form an RF group.

The members of an RF domain elect an RF domain leader to maintain a "master" power and channel scheme for the RF group. The RF domain leader analyzes real-time radio data collected by the system and calculates the master power and channel plan. The RRM algorithms try to optimize a signal strength of -65 dBm between all access points and to avoid 802.11 co-channel interference and contention as well as non-802.11 interference. The RRM algorithms employ dampening calculations to minimize system-wide dynamic changes. The end result is dynamically calculated optimal power and channel planning that is responsive to an always changing RF environment.

The RF group leader and members exchange RRM messages at a specified updated interval, which is 600 seconds by default. Between update intervals, the RF group leader sends keep-alive messages to each of the RF group members.

A controller is configured with an RF domain name, which is pushed down to all the access points joined to the controller and is used by the access points as the shared secret for generating the hashed MIC in the neighbor messages. To create an RF domain, you simply configure all of the controllers with the same RF domain name. You can configure this name in the RF-Network Name field on the Controller > General page (see Figure 22).

Figure 22 Controller > General Page

The RF domain and mobility group concepts are similar in that they both define clusters of controllers, but they are different in terms of what they do. These two concepts often get confused because the Mobility Group and RF-Network Name parameters are configured to be the same in the controller setup script. Most of the time, all controllers in an RF domain are also in the same mobility group and vice versa. However, the RF domain concept facilitates scalable, system-wide dynamic RF management while the mobility group concept is designed to facilitate scalable, system-wide mobility.

If there is any possibility that an access point joined to one controller may hear RF transmissions from an access point joined to a different controller, the controllers should be configured with the same RF domain name. If RF transmissions between access points can be heard, then system-wide RRM is recommended to avoid 802.11 interference and contention as much as possible. Furthermore, when an access point records neighbor messages that it cannot validate through the hashed MIC, the transmitting access point is reported as a rogue device. If controllers are managing neighboring access points that can hear each other and the controllers are not in the same RF domain, spurious rogue access point reports are generated to differentiate them from the legitimate access points.

Configuring QoS Profiles

Follow these steps to configure the wireless LAN controller's QoS profiles.

Step 1 Click Controller on the menu bar to access the Controller window.

Step 2 Click QoS Profiles. The QoS Profiles window appears (see Figure 23).

Figure 23 QoS Profiles Window

Step 3 To edit a QoS profile, click Edit for the QoS profile that you want to modify. The Edit QoS Profile window appears (see Figure 24).

Figure 24 Edit QoS Profile Window

Step 4 Make any changes and click Apply. However, Cisco recommends using default values for the QoS profiles.

Wireless Menu

Follow these steps to configure Cisco access points from the wireless LAN controller.

Step 1 Click Wireless on the menu bar to access the All APs window (see Figure 25).

Figure 25 All APs Window

Step 2 To view the details of a particular access point, click Detail for the access point that you want to view. The All APs > Details window appears (see Figure 26).

Figure 26 All APs > Details Window

Cisco recommends that you use the AP Name and Location fields to help identify the location of an individual access point.

Step 3 From the Wireless menu, click 802.11b/g Radios. The 802.11b/g Radios window appears (see Figure 27).

Note The asterisk next to the channel number and the power level indicates that the access point is using the default Global configuration. Therefore, the channel and power were selected by the algorithms of the controller.

Figure 27 802.11b/g Radios Window

For all indoor voice applications, Cisco highly recommends the use of diversity antennas. Antenna type and diversity can be set under Antenna on the 802.11b/g Cisco APs > Configure window (see Figure 28).

Figure 28 802.11b/g Cisco APs > Configure Window

Step 4 Click Performance Profile. The 802.11 AP Interfaces > Performance Profile window appears (see Figure 29).

Figure 29 802.11 AP Interfaces > Performance Profile Window

Table 2 shows the transmit power level values (in dBm and milliwatts) on the 2.4-GHz access point radios and the Cisco Wireless IP Phone 7920.

Table 2 Transmit Power Level Values

Transmit Power Level
dBm
mW

1

20

100

2

17

50

3

14

25

4

11

12.5

5

8

6.5

6

5

3.2

7

2

1.6

8

-1

.8


Note The AP1000 series supports power levels 1 through 5.

Step 5 In cell areas that have a high client population, it may be necessary to change the Clients field default value of 12 to a higher number.

Note The lightweight access point 802.11b/g cells can handle seven simultaneous calls.

Step 6 Uncheck the Profile Parameters Globally Controlled check box.

Step 7 Click Apply.

Step 8 From the Wireless menu, click 802.11b/g Network. The 802.11b/g Global Parameters window appears (see Figure 30).

Figure 30 802.11b/g Global Parameters Window

Cisco recommends using the data rate configuration shown in Figure 30 to ensure the best performance for the Cisco Wireless IP Phone 7920 with regard to RF delay and jitter.

Note If legacy 802.11 or 802.11b clients are using this same RF network, then 2 Mbps may be a mandatory rate. 802.11g clients can operate with this configuration. Their multicast traffic and broadcast traffic are sent at 11 Mbps, and the directed traffic is the best possible.

Note If a rate of 6, 9, 12, 18, 24, 36, 48, or 54 is set to Mandatory, the Cisco Wireless IP Phone 7920 is unable to associate.

Sample Coverage Map Generated by the Cisco Wireless Control System

Figure 31 shows nine access points in an office environment with cubes and offices. Access points AP0014.1ced.44ce, 4648, and 48ec are located in the hallways between the offices. The other access points are located in the cube area. Access points AP0014.1ced.4230, 4912, and 466c provide additional and backup coverage. Access points AP0014.1ced.494c, 4988, and 4960 provide the primary source of coverage for the voice network. The channel and transmit power level were selected automatically by the Cisco 4400 controller. Figure 32 shows the heat map generated by the Cisco Wireless Control System.

Figure 31 802.11b/g Radios Window Showing Nine Access Points

Figure 32 Heat Map Generated by Cisco Wireless Control System

In Figure 32, the access points ending with MAC IDs 4960, 4988, and 494c are the primary access points for this cube space. Access points 4230, 4912, and 466c serve as secondary access points that would increase their power if a failure occurred with a primary access point. As Figure 31 shows, the power of the secondary access points is as low as possible, and the channels are separated from those of the primary access points. The secondary access points are within a few feet of the primary access points, but the primary access points are providing the coverage. If the customer required denser coverage for battery life or increased call capacity, then the access points would be positioned differently, and their power settings would be lower.

Note The map is correctly scaled. The tested area was measured to the outside walls.

Required Commands

This section lists and describes the commands that the wireless LAN controller requires in order to support the Cisco Wireless IP Phone 7920. Specifically, it provides the commands necessary to perform the following tasks:

•Disable 802.11 aggressive load balancing

•Enable 802.11 phone support

Disabling 802.11 Aggressive Load Balancing

Follow these steps to disable 802.11 aggressive load balancing.

Note Instructions for disabling 802.11 aggressive load balancing through the GUI are provided on page 17.

Step 1 To disable aggressive load balancing, enter config load-balancing status disable.

Note Load balancing on the controller must be disabled. The Cisco Wireless IP Phone 7920 has its own algorithm for determining balance. Leaving aggressive load balancing enabled can create association flapping.

Step 2 To verify the status of load balancing, enter show load-balancing.

Step 3 To save the configuration changes, enter save config.

Enabling 802.11 Phone Support (QBSS)

Follow these steps to enable 802.11 phone support.

Step 1 To view a list of the configured wireless LANs, enter show wlan summary.

Note This command provides the wireless LAN identification needed for the SSID/VLAN on which the Cisco Wireless IP Phone 7920s reside.

Example of Results: 

Number of WLANs................... 5 


WLAN ID  WLAN Name 							 Status

------- -------------------- ---------

1       TME-AIRE							 Enabled

2       TME-AIRE-EAP-VOICE							 Enabled

3       TME-AIRE-VOICE 							 Enabled

4       TME-AIRE-GUEST 							 Enabled

5       TME-AIRE-AES 							 Enabled

Note The voice wireless LAN in this example is TME-AIRE-VOICE, which has a WLAN ID value of 3. Before the voice wireless LAN can be changed, it must be disabled.

Step 2 To configure QBSS for WLAN ID 3, enter the following commands:

config wlan disable 3
config wlan dot11-phone compat 3 (code version 3.0)
config wlan 7920-support ap-cac-limit enable (code versions 3.1 and 3.2)
config wlan enable 3

Step 3 To verify the configuration, enter show wlan 3.

Example of Results: 

WLAN Identifier.................................. 3

Network Name (SSID).............................. TME-AIRE-VOICE

Status........................................... Enabled

MAC Filtering.................................... Disabled

Broadcast SSID................................... Enabled

AAA Policy Override.............................. Disabled

Network Access Control........................... Disabled

Number of Active Clients......................... 0

Exclusion list................................... Disabled

Session Timeout.................................. Infinity

Interface........................................ Voice

DHCP Server...................................... 10.91.104.77

DHCP Address Assignment Required................. Disabled

Quality of Service............................... Platinum (voice)

WMM.............................................. Disabled

802.11e.......................................... Disabled

Dot11-Phone Mode (7920).......................... Compat

Wired Protocol................................... None

IPv6 Support..................................... Disabled

Radio Policy................................. 802.11B and 802.11G only

Note The Dot11-Phone Mode (7920) entry is shown as "Compat."

Step 4 To save the configuration changes, enter save config.

Additional Show Commands

This section lists and describes some additional show commands of interest:

1. show ap auto-rf 802.11b xxxxxx (where xxxxxx is the access point name)—Shows the radio frequency performance as seen by the access point.

Example of Results: 

Number of Slots.................................. 2

AP Name.......................................... TME_LJR_7920_1

MAC Address...................................... 00:0b:85:1b:df:d0

  Radio Type..................................... RADIO_TYPE_80211b/g

  Noise Information

    Noise Profile................................ PASSED

    Channel 1....................................  -93 dBm

    Channel 2....................................  -90 dBm

    Channel 3....................................  -89 dBm

    Channel 4....................................  -89 dBm

    Channel 5....................................  -90 dBm

    Channel 6....................................  -88 dBm

    Channel 7....................................  -91 dBm

    Channel 8....................................  -91 dBm

    Channel 9....................................  -92 dBm

    Channel 10...................................  -95 dBm

    Channel 11...................................  -95 dBm

  Interference Information

    Interference Profile......................... FAILED

    Channel 1....................................  -69 dBm @ 31% busy

    Channel 2....................................  -58 dBm @ 26% busy

    Channel 3....................................  -71 dBm @ 18% busy

    Channel 4....................................  -70 dBm @ 29% busy

    Channel 5....................................  -67 dBm @ 25% busy

    Channel 6....................................  -60 dBm @ 15% busy

    Channel 7....................................  -72 dBm @ 15% busy

    Channel 8....................................  -76 dBm @ 23% busy

    Channel 9....................................  -69 dBm @ 16% busy

    Channel 10...................................  -70 dBm @ 22% busy

    Channel 11...................................  -68 dBm @ 26% busy

  Load Information

    Load Profile................................. PASSED

    Receive Utilization.......................... 0%

    Transmit Utilization......................... 0%

    Channel Utilization.......................... 26%

    Attached Clients............................. 2 clients

  Coverage Information

    Coverage Profile............................. PASSED

    Failed Clients............................... 0 clients

  Client Signal Strengths

    RSSI -100 dbm................................ 0 clients

    RSSI  -92 dbm................................ 0 clients

    RSSI  -84 dbm................................ 0 clients

    RSSI  -76 dbm................................ 0 clients

    RSSI  -68 dbm................................ 0 clients

    RSSI  -60 dbm................................ 1 clients

    RSSI  -52 dbm................................ 1 clients

  Client Signal To Noise Ratios

    SNR    0 dbm................................. 0 clients

    SNR    5 dbm................................. 0 clients

    SNR   10 dbm................................. 0 clients

    SNR   15 dbm................................. 0 clients

    SNR   20 dbm................................. 0 clients

    SNR   25 dbm................................. 0 clients

    SNR   30 dbm................................. 0 clients

    SNR   35 dbm................................. 0 clients

    SNR   40 dbm................................. 1 clients

    SNR   45 dbm................................. 1 clients

  Nearby APs

  Channel Assignment Information

    Current Channel Average Energy............... -68 dBm

    Previous Channel Average Energy.............. -51 dBm

    Channel Change Count......................... 21

    Last Channel Change Time..................... Thu Jul  7 12:18:03 2005

    Recommend Best Channel....................... 11

  RF Parameter Recommendations

    Power Level.................................. 1

    RTS/CTS Threshold............................ 2347

    Fragmentation Threshold...................... 2346

    Antenna Pattern.............................. 0

2. show 802.11b—Shows the radio settings on the access point. 

802.11b Network.................................. Enabled

11g Support...................................... Enabled

802.11b/g Operational Rates

    802.11b/g 1M Rate............................ Disabled

    802.11b/g 2M Rate............................ Disabled

    802.11b/g 5.5M Rate.......................... Disabled

    802.11b/g 11M Rate........................... Mandatory

    802.11g 6M Rate.............................. Disabled

    802.11g 9M Rate.............................. Disabled

    802.11g 12M Rate............................. Supported

    802.11g 18M Rate............................. Supported

    802.11g 24M Rate............................. Supported

    802.11g 36M Rate............................. Supported

    802.11g 48M Rate............................. Supported

    802.11g 54M Rate............................. Supported

Beacon Interval.................................. 100

CF Pollable mode................................. Disabled

CF Poll Request mandatory........................ Disabled

CFP Period....................................... 4

CFP Maximum Duration............................. 60

Default Channel.................................. 1

--More-- or (q)uit

Default Tx Power Level........................... 1

DTIM Period...................................... 1

ED Threshold..................................... -50

Fragmentation Threshold.......................... 2346

Long Retry Limit................................. 4

Maximum Rx Life Time............................. 512

Max Tx MSDU Life Time............................ 512

Medium Occupancy Limit........................... 100

PBCC mandatory................................... Disabled

Pico-Cell Status................................. Disabled

RTS Threshold.................................... 2347

Short Preamble mandatory......................... Enabled

Short Retry Limit................................ 7

3. show advanced 802.11b summary—Shows advanced radio settings on the access point.

Example of Results: 

AP Name                          Channel     Tx Power Level

-------------------------------- ----------- -------------

TME_LJR_7920_1                       11*           1*

4. show qos queue_length all—Shows the QoS queues and depth.

Example of Results: 

Platinum queue length............................ 100

Gold queue length................................  75

Silver queue length..............................  50

Bronze queue length..............................  25

5. show network—Shows network details.

Example of Results: 

RF-Network Name............................. Test-TME

Web Mode.................................... Disabled

Secure Web Mode............................. Enabled

Secure Shell (ssh).......................... Enabled

Telnet...................................... Enabled

Ethernet Multicast Mode..................... Disabled

User Idle Timeout........................... 300 seconds

ARP Idle Timeout............................ 300 seconds

ARP Unicast Mode............................ Disabled

Cisco AP Default Master..................... Disabled

Mgmt Via Wireless Interface................. Enabled

Bridge AP Zero Config....................... Disabled

Bridge Shared Secret........................

Allow Old Bridging APs To Authenticate...... Disabled

Over The Air Provisioning of APs ........... Enabled

Mobile Peer to Peer Blocking................ Disabled

Apple Talk ................................. Disabled

AP Fallback ................................ Enabled

Web Auth Redirect Ports .................... 80

Fast SSID Change ........................... Disabled

6. show client detail 00:0d:28:2e:68:04—Shows client details.

Example of Results: 

Client MAC Address............................... 00:0d:28:2e:68:04

Client Username ................................. N/A

AP MAC Address................................... 00:0b:85:1b:df:d0

Client State..................................... Associated

Wireless LAN Id.................................. 3

IP Address....................................... 10.30.0.200

Association Id................................... 4

Authentication Algorithm......................... Open System

Reason Code...................................... 0

Status Code...................................... 0

Session Timeout.................................. 0

Re-Authentication Timeout........................ 0

Remaining Re-Authentication Time................. Timer is not running

Mirroring........................................ Disabled

QoS Level........................................ Platinum

Diff Serv Code Point (DSCP)...................... Disabled

802.1P Priority Tag.............................. Disabled

Mobility State................................... Local

Mobility Move Count.............................. 0

Security Policy Completed........................ Yes

Policy Manager State............................. RUN

Policy Manager Rule Created...................... No

NPU Fast Fast Notified........................... Yes

Policy Type...................................... N/A

Encryption Cipher................................ None

EAP Type......................................... Unknown

Interface........................................ voice

VLAN............................................. 30

Client capabilities:

      CF Pollable................................ Not implemented

      CF Poll Request............................ Not implemented

      Short Preamble............................. Implemented

      PBCC....................................... Not implemented

      Channel Agility............................ Not implemented

      Listen Interval............................ 0

Client Statistics:

      Number of Bytes Received................... 179202

      Number of Bytes Sent....................... 13389

      Number of Packets Received................. 6236

      Number of Packets Sent..................... 156

      Number of Policy Errors.................... 0

      Radio Signal Strength Indicator............ -53 dBm

      Signal to Noise Ratio...................... 42 dB

Nearby AP Statistics:

     TxExcessiveRetries: 0

     TxRetries: 0

     RtsSuccessCnt: 0

     RtsFailCnt: 0

     TxFiltered: 0

TxRateProfile: [0,0,0,0,0,0,0,0,0,0,0,0]

      TME_LJR_7920_1(slot 1) 5 seconds ago....... -52 dBm

Viewing the Details of a Cisco Wireless