Cisco Unified Wireless Ap Interactions; Ap Association - Cisco 7925G Administration Manual

Cisco Unified Wireless AP Interactions

Network protocol
Transport Layer
Security (TLS)
User Datagram
Protocol (UDP)
Related Topics
Phone Startup Process, on page 64
VoIP Wireless Network Components, on page 32
DHCP Settings, on page 121
Cisco Unified Wireless AP Interactions
Wireless 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 make the phone call inaudible.
Wireless IP Phones users are mobile and often roam across a campus or between floors in a building while
connected to a call. In contrast, data users remain in one place or occasionally move to another location. The
ability to roam while maintaining a call is one of the advantages of wireless voice, so RF coverage needs to
include stairwells, elevators, quiet corners outside conference rooms, passageways and so on.
To ensure good voice quality and optimal RF signal coverage, you must perform a site survey. The site survey
determines the AP platform and antenna type, AP placement, channel assignments and transmit power levels
that are required for the deployment.
After you deploy and use wireless voice, you should continue to perform postinstallation site surveys. When
you add a group of new users, install more equipment, or stack large amounts of inventory, you are changing
the wireless environment. A postinstallation survey verifies that the AP coverage remains adequate for optimal
voice communications.
Related Topics
Site Survey Verification, on page 44

AP Association

At startup, the Cisco Unified Wireless IP Phone scans for APs with SSIDs and encryption types that it
recognizes. The phone builds and maintains a list of eligible APs and uses the following variables to determine
the best AP.
Cisco Unified Wireless IP Phone 7925G, 7925G-EX, and 7926G Administration Guide
34
Purpose
TLS is a standard protocol for securing
and authenticating communications.
Connectionless messaging protocol
for delivery of data packets.
VoIP Wireless Network
Usage notes
When security is implemented, Cisco
Unified Wireless IP Phones use the TLS
protocol when securely registering with Cisco
Unified Communications Manager.
Cisco Unified Wireless IP Phones receive
and process UDP messages. RTP voice traffic
runs over UDP.