Avaya Communication Server 1000 Installation And Commissioning Manual page 230

Troubleshooting WLAN IP Telephony installations
• Use appropriate security mechanisms for the wireless telephones and the requirements
of the environment:
- Avaya WLAN IP Telephony telephones support WEP, WPA-PSK, or WPA2-PSK.
- Avaya recommends that you always use Open Authentication because it is more
secure.
- You can use a No WEP temporary SSID during troubleshooting so that you can
gather wireless data with visibility into the SpectraLink Radio Protocol (SRP) data
structures.
After troubleshooting is complete, disable this temporary SSID.
• Ensure 15% to 20% cell overlap between AP signal coverage areas.
• Always use two antennas on each AP.
- Enable diversity in each AP.
- Use full diversity in each AP, not partial or one-way diversity.
- Make this the standard for the RF environment.
Very special circumstances must exist before you make changes.
• Provide priority for IP protocol 119 packets:
- Assign voice packets to an AP QoS Class of Service with a latency of 10 ms or less.
- Configure priority for both directions in both interfaces.
Priority gets the voice packets ahead of the queue inside the AP, whether the
interface is 802.11b radio or Ethernet.
- Configure Voice Radio Contention Window Minimum to 0.
- Configure Voice Radio Contention Window Maximum to 0.
- Configure Voice Fixed Slot Size to 2.
- Configure Voice Transmit Opportunity to 0.
On the Cisco Aironet 1200 Series with code 12.3(8)JA3 or later, click WFA Default on
QoS Radio 802.11g. Access the Categories page and then configure the parameters for
voice. This version has two boxes to configure for each parameter. Do not click Optimize
for Voice.
• Enable WiFi Multi-Media (WMM) on the radio interface.
• Use VLAN support in the AP and in the network for security and management:
- Assign the voice SSID to a VLAN.
- Enable the voice VLAN across the network between the AP, to the SVP, to the
Signaling Server, to the Call Manager and all components in between.
230 Avaya WLAN IP Telephony Installation and Commissioning November 2010