Wlans And Roaming; Bluetooth Wireless Technology; Voip Wireless Network Components; Cisco Unified Wireless Ap Interactions - Cisco 8961 Administration Manual

WLANs and Roaming

WLANs and Roaming
The Cisco Unified IP Phone 9971 supports Cisco Centralized Key Management (CCKM), a centralized key
management protocol, and provides a cache of session credentials on the wireless domain server (WDS). APs
must register to the WDS for fast roaming to work. CCKM is also supported on the Cisco Unified Wireless
LAN Controller alone.
The Cisco Unified IP Phone 9971 supports CCKM with 802.1x+WEP or WPA(TKIP) only. CCKM is not
supported with WPA2 or WPA(AES). For details about CCKM, see the Cisco Fast Secure Roaming Application
Note at:
http://www.cisco.com/en/US/products/hw/wireless/ps4570/prod_technical_reference09186a00801c5223.html
Related Topics
Voice QoS in Wireless Network, on page 91
VoIP WLAN Deployment, on page 97

Bluetooth Wireless Technology

Bluetooth enables low-bandwidth wireless connections within a range of 30 feet (10 meters). The best
performance is in the 3- to 6-foot (1- to 2-meter) range. Bluetooth wireless technology operates in the 2.4
GHz band, which is the same as the 802.11b/g band. Interference issues can occur. We recommend that you:
• Use 802.11a that operates in the 5 GHz band.
• Reduce the proximity of other 802.11b/g devices, Bluetooth devices, microwave ovens, and large metal
Related Topics
Bluetooth Wireless Headsets, on page 63

VoIP Wireless Network Components

The Cisco Unified IP Phone must interact with several network components in the WLAN to successfully
place and receive calls.

Cisco Unified Wireless AP Interactions

Cisco Unified IP Phones use the same APs as wireless data devices. However, voice traffic over a WLAN
requires different equipment configurations and layouts than a WLAN that is used exclusively for data traffic.
Data transmission can tolerate a higher level of RF noise, packet loss, and channel contention than voice
transmission. Packet loss during voice transmission can cause choppy or broken audio and can make the phone
call inaudible. Packet errors can also cause blocky or frozen video.
Because the Cisco Unified IP Phone 9971 is a desktop (not mobile) phone, changes in the local environment
can cause phones to roam between access points and can affect the voice and video performance. In contrast,
data users remain in one place or occasionally move to another location. The ability to roam while maintaining
Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager
10.0 (SIP)
90
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objects.
VoIP Wireless Network