Cisco Unified Wireless IP Phone 7920 Design and Deployment Guide - Deployments and Configuration [Cisco Unified IP Phones 7900 Series]

Table Of Contents

Deployments and Configuration

Cisco 7920 Phone Configuration (for Installation)

Gathering Information

Phone Configuration

Configuration Verification

AP Configuration (for Installation)

Deployments and Configuration

The following sections describe deployment and configuration steps for the Cisco 7920 Wireless IP Phones and the Cisco Aironet Access Points:

•Cisco 7920 Phone Configuration (for Installation)

•AP Configuration (for Installation)

Cisco 7920 Phone Configuration (for Installation)

This section describes how to verify the main configuring settings for the Cisco 7920 Wireless IP Phone.

Gathering Information

Before configuring the Cisco 7920 Wireless IP Phone, it is important to check the phone hardware revision number and firmware version.

Hardware Revision Number

The phone hardware should be Rev 1 or later. You can determine the hardware revision number in one of the following ways:

•By removing the battery and reading the sticker in the phone

•By navigating through the phone menus as follows: Menu > Phone Settings > Phone Status > Hardware Info

Any version earlier than Rev 1 indicates a non-production phone and can cause unpredictable problems. Such phones are not supported by Cisco TAC and should be used only for demonstration purposes in the field.

Phone Firmware

The firmware version can be found by navigating through the phone menus as follows: Menu > Phone Settings > Phone Status > Firmware Info > Firmware Version. The phone should be running the most current load, which can be found under IP Phones on the Cisco.com Software Download center at

http://www.cisco.com/pcgi-bin/tablebuild.pl/ip-7900ser-crypto

Note To be fully compatible with the guidelines in this document, Cisco recommends using the most current version of the firmware for the Cisco 7920 Wireless IP Phone. Cisco also recommends that you frequently check the Cisco.com Software Download site for the latest phone firmware.

Phone Configuration

You can configure Cisco 7920 Wireless IP Phones in either of the following ways:

•By using the keypad on the phone (Refer to the Cisco Wireless IP Phone 7920 User Guide.)

•With a PC, by using the Cisco 7920 Configuration Utility and the USB cable (Refer to the Cisco Wireless IP Phone 7920 Administrator Guide.)

The documentation for both of these processes is available at

http://www.cisco.com

Configuration Verification

Verify the following settings to ensure that the Cisco 7920 phone works properly:

•Network configuration settings

The network configuration settings can be verified by navigating to Menu > Network Config > Current Config. Check that the DHCP server or static settings (IP Address, Subnet Mask, Primary Gateway, Primary TFTP, and Primary/Secondary DNS) are correct for the associated network.

•Wireless settings

The wireless settings can be verified by navigating to Menu > Network Config > 802.11b Configuration. Check to ensure that the SSID(s) and authentication/encryption type are correct and are for the voice VLAN. If using WEP, verify that the WEP key has been entered correctly (and identically) on both the phone and the AP. If using LEAP, ensure that the username and password are entered identically on both the phone and the ACS (or local LEAP server on a Cisco AP). If authentication fails, Cisco recommends simply re-entering this information on the phone because it is quite easy to enter these values incorrectly.

AP Configuration (for Installation)

This section identifies only the key AP configuration options that are required for optimal voice performance, and it should not to be considered a comprehensive list of configuration options for a production AP. For detailed information and full AP configurations, refer to the Cisco IOS Software Configuration Guide for Cisco Aironet Access Points, available at

http://www.cisco.com

The section on Example Configurations for AP and RADIUS Server, page C-1, lists the Cisco IOS text output from the recommended configuration outlined in this chapter.

Note Cisco requires that all APs used with voice calls be either AIR-AP350 Series, AIR-AP1100 Series, or AIR-AP1200 Series. Cisco also recommends that APs used for production run a minimum Cisco IOS release of 12.2.(15)JA.

Cisco IOS is required on voice APs because VxWorks will no longer add new features that are required for successful voice deployments, such as Address Resolution Protocol (ARP) caching.

Execute the following configuration steps on the APs. (Figure 7-1 through Figure 7-10 illustrate the web interface of a Cisco IOS AP.)

Step 1 Assign a unique name and unique IP address to each AP. When doing this, note the radio MAC address of the AP in relation to the AP name and IP address. This information will allow for easier identification of APs because almost all site survey tools use radio MAC addresses to identify the APs.

Step 2 Click System Software and check the Cisco IOS version of the AP (see Figure 7-1). If it is not the recommended version, update it to the recommended version.

Figure 7-1 AP System Software Version: IOS

Step 3 Cisco recommends separating voice traffic from data traffic through the use of VLANs. Create a minimum of two VLANs. (The VLAN number assigned to the AP must coincide with the wired VLAN number.) One VLAN must be designated as the Native VLAN, which will carry all administrative traffic. This VLAN can also be used to carry data traffic. It must also be identified as the Native VLAN on the switch and can be configured under Services > VLAN (see Figure 7-2).

Note Ensure the switch port is properly configured prior to applying AP VLAN configurations. Otherwise, when enabling VLANs, connectivity to the AP via the wired port will be lost until the switch port is properly configured.

Figure 7-2 AP VLAN Configuration

Step 4 Click Security > SSID Manager and assign an SSID to each VLAN (see Figure 7-3).

Figure 7-3 AP SSID Configuration

Step 5 The purpose of using data and voice VLANs is to enable specific QoS settings on all traffic on the VLAN. Separating traffic by VLAN and using the "Default QoS for all traffic on a VLAN" frees the AP from having to examine each packet to identify the type of traffic it contains. To apply these settings, click Services > QoS (see Figure 7-4).

a. Create a policy for data and give it a default CoS value of 0, or Background data.

Figure 7-4 AP QoS Policy Settings Configuration: Data

b. Perform the same procedure for a voice VLAN but set the default CoS to level 6, or voice traffic (see Figure 7-5).

Figure 7-5 AP QoS Policy Settings Configuration: Voice

Step 6 After creating the policies in the previous steps, use the same configuration page to apply those policies to the proper VLANs on the radio interface, both incoming and outgoing only (see Figure 7-6). These QoS profiles are not added to the wired interface because that 100-Mbps connection is rarely the bottleneck, and applying the QoS profiles to this interface would put an unnecessary load on the processor.

Figure 7-6 AP QoS Policy Setting Configuration: Assigning Policies to VLANs

Step 7 Clicking on the tab Radio-802.11b (or in some cases 802.11g) Access Categories opens a page where you can change the values of these classifications. Cisco recommends that you do not change any of these settings. Figure 7-7 shows the defaults values for reference.

Figure 7-7 AP Access Categories Configuration: Contention Window Size (cwMin, cwMax)

Step 8 Under the Advanced tab for QoS, ensure that the QoS Element for Wireless Phones is enabled (see Figure 7-8).

Figure 7-8 AP QoS Element Configuration

Step 9 A common AP configuration error concerns ARP caching. The phones expect this option to be enabled on the AP, but it is disabled be default on the AP. For optimal performance, Cisco recommends enabling ARP caching on the AP, especially when using Wi-Fi devices capable of power management. If you are using Cisco Aironet cards, ARP caching is enabled by default, but you should ensure that this setting has not be changed by any central client management groups. To configure ARP caching on the AP, select Services > ARP Caching (see Figure 7-9).

Note Cisco highly recommends that you enable ARP caching on all APs.

Figure 7-9 AP ARP Caching Configuration

Step 10 When conducting a site survey, it is imperative to adjust the AP channel transmit power and data rates based on the guidelines listed in the chapter on Radio Frequency and Site Survey. These settings can be modified by selecting Network Interfaces > Radio0-802.11B > Settings (see Figure 7-10).

Note Cisco highly recommends enabling Dynamic Transmit Power Control (DTPC) on the AP by using the Limit Client Power field in the user interface (or the power client command in Cisco IOS) to ensure that the APs and Cisco 7920 phones use the same transmit power to avoid one-way audio. If you are not using a version of the firmware that supports DTPC (such as version 1.0(8) or later), configure the Cisco 7920 phones to use the same transmit power as configured on the APs. If the power of the APs varies, set the transmit power of the Cisco 7920 phones to the same level as configured on the AP with the highest transmit power.

Note Cisco highly recommends that you do not use the option to Search for Least Congested Channel but set the channel manually instead.

Figure 7-10 AP Channel Transmit Power Configuration

Step 11 Cisco highly recommends that all deployments use high levels of security on both their data and voice VLANs. For the data VLAN, Cisco highly recommends that you use some type of 802.1x authentication and encryption system. For voice, LEAP and WEP are both currently available. To enhance security on the voice VLAN, you can use wired-side access control lists (ACLs) to limit the traffic to Cisco CallManager and the APs on the voice VLAN.

Step 12 Cisco highly recommends filtering to eliminate any unnecessary traffic that might cause delays in the essential wireless traffic. Although a Cisco AP is capable of performing this task, Cisco recommends that the filtering be performed on a Layer 3 switch connected to the AP because the switch performs the filtering in hardware and significantly reduces the processing time required to perform this task. If no Layer 3 switch is available, the APs can perform Layer 3 filtering, but this task might affect AP performance.

a. Cisco highly recommends that all traffic not required for the AP and RF devices be blocked or filtered at the closest switch. At the AP or switch port, filter all protocols that are not required by the data clients and the voice clients.

For example, unless your wireless data clients are running IBM 3278 terminal emulation, block all Systems Network Architecture (SNA) traffic from the data and voice VLAN. If you are using IBM 3278 data on the data VLAN, then block SNA traffic on the voice VLAN. In many network environments, protocols such as NetBUI, NetWare, and SNA create a large amount of unnecessary wireless traffic that can easily be filtered.

b. The filters for traffic not needed to support WLAN clients should be on all VLANs on the AP.

For example, the radio would send an SNA broadcast packet for each VLAN on the AP. If there are four VLANs on the AP, there is the potential for that packet to be sent four times. If the client is in an area of overlapping AP coverage for the same channel, then the Cisco 7920 phone will see that unusable SNA packet eight times. This type of unnecessary traffic adversely affects voice quality because it consumes bandwidth needed for voice traffic.

Note The section on Example Port Configurations for Voice Operations, page D-1, identifies many of the key packet types needed for the Cisco 7920 Wireless IP Phone.

c. While Ethernet switch ports can transmit and receive at 100 Mbps, 802.11b APs have a throughput of only 11 Mbps (about 7 Mbps of actual throughput) or less through the RF port. Because of the bursty nature of some network traffic, this throughput mismatch means that the AP will have to drop packets, thus adding excessive processor load to the AP. An alternative is to configure the first-hop switch to drop these packets using policing and rate limiting features. Thus, the switch port to which the AP is connected can be rate-limited to a throughput of 11 Mbps or less.

If you are using a Cisco Aironet AP equipped for 802.11g or 802.11a, increase the rate limit to the total throughput of the RF ports, as follows:

–802.11g = 54 Mbps (about 22 Mbps of actual throughput)

–802.11a + 802.11g = 100 Mbps (no rate limiting necessary)

–802.11a + 802.11b = 64 Mbps (about 42 Mbps of actual throughput)

Step 13 Optionally, you can filter all video prioritized traffic at the switch so that it cannot be sent to the APs. The number of calls per AP has been characterized without video prioritized traffic on the network. Prioritized video traffic (those packets marked with CoS in the range of 3 to 5, inclusive) significantly diminishes the call capacity of an AP because it is granted access to the wireless media at a higher priority than best-effort data.

Step 14 If there are 802.11g APs in the network, then the 802.11g protection mechanism must be enabled to make sure that 802.11b clients (such as the Cisco 7920 phone) do not have packet collisions with 802.11g packets. This protection mechanism is enabled automatically on the AP if the 802.11b data rates are enabled.

	Cisco Unified Wireless IP Phone 7920 Design and Deployment Guide
	Deployments and Configuration
Cisco Unified Wireless IP Phone 7920 Design and Deployment Guide Preface Overview of Cisco Wireless IP Telephony Radio Frequency and Site Survey Security Wireless Network Infrastructure Layer 2 and Layer 3 Roaming Quality of Service Deployments and Configuration Wireless IP Telephony Verification Troubleshooting the Cisco 7920 Phone Advanced Cisco 7920 Commands Site Survey RF Recommendations Example Configurations for AP and RADIUS Server Example Port Configurations for Voice Operations Site Information Help Request Form User Support Help Request Form Using Cisco Emergency Responder for E911 Calls with the Cisco 7920 Phone Guidelines and Limitations Maximum Throughput Calculations for 802.11b WLAN Index	Download this chapter Deployments and Configuration Download the complete book Cisco Unified Wireless IP Phone 7920 Design and Deployment Guide (PDF - 3 MB) Table Of Contents Deployments and Configuration Cisco 7920 Phone Configuration (for Installation) Gathering Information Phone Configuration Configuration Verification AP Configuration (for Installation) Deployments and Configuration The following sections describe deployment and configuration steps for the Cisco 7920 Wireless IP Phones and the Cisco Aironet Access Points: •Cisco 7920 Phone Configuration (for Installation) •AP Configuration (for Installation) Cisco 7920 Phone Configuration (for Installation) This section describes how to verify the main configuring settings for the Cisco 7920 Wireless IP Phone. Gathering Information Before configuring the Cisco 7920 Wireless IP Phone, it is important to check the phone hardware revision number and firmware version. Hardware Revision Number The phone hardware should be Rev 1 or later. You can determine the hardware revision number in one of the following ways: •By removing the battery and reading the sticker in the phone •By navigating through the phone menus as follows: Menu > Phone Settings > Phone Status > Hardware Info Any version earlier than Rev 1 indicates a non-production phone and can cause unpredictable problems. Such phones are not supported by Cisco TAC and should be used only for demonstration purposes in the field. Phone Firmware The firmware version can be found by navigating through the phone menus as follows: Menu > Phone Settings > Phone Status > Firmware Info > Firmware Version. The phone should be running the most current load, which can be found under IP Phones on the Cisco.com Software Download center at http://www.cisco.com/pcgi-bin/tablebuild.pl/ip-7900ser-crypto Note To be fully compatible with the guidelines in this document, Cisco recommends using the most current version of the firmware for the Cisco 7920 Wireless IP Phone. Cisco also recommends that you frequently check the Cisco.com Software Download site for the latest phone firmware. Phone Configuration You can configure Cisco 7920 Wireless IP Phones in either of the following ways: •By using the keypad on the phone (Refer to the Cisco Wireless IP Phone 7920 User Guide.) •With a PC, by using the Cisco 7920 Configuration Utility and the USB cable (Refer to the Cisco Wireless IP Phone 7920 Administrator Guide.) The documentation for both of these processes is available at http://www.cisco.com Configuration Verification Verify the following settings to ensure that the Cisco 7920 phone works properly: •Network configuration settings The network configuration settings can be verified by navigating to Menu > Network Config > Current Config. Check that the DHCP server or static settings (IP Address, Subnet Mask, Primary Gateway, Primary TFTP, and Primary/Secondary DNS) are correct for the associated network. •Wireless settings The wireless settings can be verified by navigating to Menu > Network Config > 802.11b Configuration. Check to ensure that the SSID(s) and authentication/encryption type are correct and are for the voice VLAN. If using WEP, verify that the WEP key has been entered correctly (and identically) on both the phone and the AP. If using LEAP, ensure that the username and password are entered identically on both the phone and the ACS (or local LEAP server on a Cisco AP). If authentication fails, Cisco recommends simply re-entering this information on the phone because it is quite easy to enter these values incorrectly. AP Configuration (for Installation) This section identifies only the key AP configuration options that are required for optimal voice performance, and it should not to be considered a comprehensive list of configuration options for a production AP. For detailed information and full AP configurations, refer to the Cisco IOS Software Configuration Guide for Cisco Aironet Access Points, available at http://www.cisco.com The section on Example Configurations for AP and RADIUS Server, page C-1, lists the Cisco IOS text output from the recommended configuration outlined in this chapter. Note Cisco requires that all APs used with voice calls be either AIR-AP350 Series, AIR-AP1100 Series, or AIR-AP1200 Series. Cisco also recommends that APs used for production run a minimum Cisco IOS release of 12.2.(15)JA. Cisco IOS is required on voice APs because VxWorks will no longer add new features that are required for successful voice deployments, such as Address Resolution Protocol (ARP) caching. Execute the following configuration steps on the APs. (Figure 7-1 through Figure 7-10 illustrate the web interface of a Cisco IOS AP.) Step 1 Assign a unique name and unique IP address to each AP. When doing this, note the radio MAC address of the AP in relation to the AP name and IP address. This information will allow for easier identification of APs because almost all site survey tools use radio MAC addresses to identify the APs. Step 2 Click System Software and check the Cisco IOS version of the AP (see Figure 7-1). If it is not the recommended version, update it to the recommended version. Figure 7-1 AP System Software Version: IOS Step 3 Cisco recommends separating voice traffic from data traffic through the use of VLANs. Create a minimum of two VLANs. (The VLAN number assigned to the AP must coincide with the wired VLAN number.) One VLAN must be designated as the Native VLAN, which will carry all administrative traffic. This VLAN can also be used to carry data traffic. It must also be identified as the Native VLAN on the switch and can be configured under Services > VLAN (see Figure 7-2). Note Ensure the switch port is properly configured prior to applying AP VLAN configurations. Otherwise, when enabling VLANs, connectivity to the AP via the wired port will be lost until the switch port is properly configured. Figure 7-2 AP VLAN Configuration Step 4 Click Security > SSID Manager and assign an SSID to each VLAN (see Figure 7-3). Figure 7-3 AP SSID Configuration Step 5 The purpose of using data and voice VLANs is to enable specific QoS settings on all traffic on the VLAN. Separating traffic by VLAN and using the "Default QoS for all traffic on a VLAN" frees the AP from having to examine each packet to identify the type of traffic it contains. To apply these settings, click Services > QoS (see Figure 7-4). a. Create a policy for data and give it a default CoS value of 0, or Background data. Figure 7-4 AP QoS Policy Settings Configuration: Data b. Perform the same procedure for a voice VLAN but set the default CoS to level 6, or voice traffic (see Figure 7-5). Figure 7-5 AP QoS Policy Settings Configuration: Voice Step 6 After creating the policies in the previous steps, use the same configuration page to apply those policies to the proper VLANs on the radio interface, both incoming and outgoing only (see Figure 7-6). These QoS profiles are not added to the wired interface because that 100-Mbps connection is rarely the bottleneck, and applying the QoS profiles to this interface would put an unnecessary load on the processor. Figure 7-6 AP QoS Policy Setting Configuration: Assigning Policies to VLANs Step 7 Clicking on the tab Radio-802.11b (or in some cases 802.11g) Access Categories opens a page where you can change the values of these classifications. Cisco recommends that you do not change any of these settings. Figure 7-7 shows the defaults values for reference. Figure 7-7 AP Access Categories Configuration: Contention Window Size (cwMin, cwMax) Step 8 Under the Advanced tab for QoS, ensure that the QoS Element for Wireless Phones is enabled (see Figure 7-8). Figure 7-8 AP QoS Element Configuration Step 9 A common AP configuration error concerns ARP caching. The phones expect this option to be enabled on the AP, but it is disabled be default on the AP. For optimal performance, Cisco recommends enabling ARP caching on the AP, especially when using Wi-Fi devices capable of power management. If you are using Cisco Aironet cards, ARP caching is enabled by default, but you should ensure that this setting has not be changed by any central client management groups. To configure ARP caching on the AP, select Services > ARP Caching (see Figure 7-9). Note Cisco highly recommends that you enable ARP caching on all APs. Figure 7-9 AP ARP Caching Configuration Step 10 When conducting a site survey, it is imperative to adjust the AP channel transmit power and data rates based on the guidelines listed in the chapter on Radio Frequency and Site Survey. These settings can be modified by selecting Network Interfaces > Radio0-802.11B > Settings (see Figure 7-10). Note Cisco highly recommends enabling Dynamic Transmit Power Control (DTPC) on the AP by using the Limit Client Power field in the user interface (or the power client command in Cisco IOS) to ensure that the APs and Cisco 7920 phones use the same transmit power to avoid one-way audio. If you are not using a version of the firmware that supports DTPC (such as version 1.0(8) or later), configure the Cisco 7920 phones to use the same transmit power as configured on the APs. If the power of the APs varies, set the transmit power of the Cisco 7920 phones to the same level as configured on the AP with the highest transmit power. Note Cisco highly recommends that you do not use the option to Search for Least Congested Channel but set the channel manually instead. Figure 7-10 AP Channel Transmit Power Configuration Step 11 Cisco highly recommends that all deployments use high levels of security on both their data and voice VLANs. For the data VLAN, Cisco highly recommends that you use some type of 802.1x authentication and encryption system. For voice, LEAP and WEP are both currently available. To enhance security on the voice VLAN, you can use wired-side access control lists (ACLs) to limit the traffic to Cisco CallManager and the APs on the voice VLAN. Step 12 Cisco highly recommends filtering to eliminate any unnecessary traffic that might cause delays in the essential wireless traffic. Although a Cisco AP is capable of performing this task, Cisco recommends that the filtering be performed on a Layer 3 switch connected to the AP because the switch performs the filtering in hardware and significantly reduces the processing time required to perform this task. If no Layer 3 switch is available, the APs can perform Layer 3 filtering, but this task might affect AP performance. a. Cisco highly recommends that all traffic not required for the AP and RF devices be blocked or filtered at the closest switch. At the AP or switch port, filter all protocols that are not required by the data clients and the voice clients. For example, unless your wireless data clients are running IBM 3278 terminal emulation, block all Systems Network Architecture (SNA) traffic from the data and voice VLAN. If you are using IBM 3278 data on the data VLAN, then block SNA traffic on the voice VLAN. In many network environments, protocols such as NetBUI, NetWare, and SNA create a large amount of unnecessary wireless traffic that can easily be filtered. b. The filters for traffic not needed to support WLAN clients should be on all VLANs on the AP. For example, the radio would send an SNA broadcast packet for each VLAN on the AP. If there are four VLANs on the AP, there is the potential for that packet to be sent four times. If the client is in an area of overlapping AP coverage for the same channel, then the Cisco 7920 phone will see that unusable SNA packet eight times. This type of unnecessary traffic adversely affects voice quality because it consumes bandwidth needed for voice traffic. Note The section on Example Port Configurations for Voice Operations, page D-1, identifies many of the key packet types needed for the Cisco 7920 Wireless IP Phone. c. While Ethernet switch ports can transmit and receive at 100 Mbps, 802.11b APs have a throughput of only 11 Mbps (about 7 Mbps of actual throughput) or less through the RF port. Because of the bursty nature of some network traffic, this throughput mismatch means that the AP will have to drop packets, thus adding excessive processor load to the AP. An alternative is to configure the first-hop switch to drop these packets using policing and rate limiting features. Thus, the switch port to which the AP is connected can be rate-limited to a throughput of 11 Mbps or less. If you are using a Cisco Aironet AP equipped for 802.11g or 802.11a, increase the rate limit to the total throughput of the RF ports, as follows: –802.11g = 54 Mbps (about 22 Mbps of actual throughput) –802.11a + 802.11g = 100 Mbps (no rate limiting necessary) –802.11a + 802.11b = 64 Mbps (about 42 Mbps of actual throughput) Step 13 Optionally, you can filter all video prioritized traffic at the switch so that it cannot be sent to the APs. The number of calls per AP has been characterized without video prioritized traffic on the network. Prioritized video traffic (those packets marked with CoS in the range of 3 to 5, inclusive) significantly diminishes the call capacity of an AP because it is granted access to the wireless media at a higher priority than best-effort data. Step 14 If there are 802.11g APs in the network, then the 802.11g protection mechanism must be enabled to make sure that 802.11b clients (such as the Cisco 7920 phone) do not have packet collisions with 802.11g packets. This protection mechanism is enabled automatically on the AP if the 802.11b data rates are enabled.
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