Understanding WLAN Standards and Technologies
Figure 6-1
IP telephony.
Figure 6-1
When a Cisco Unified IP Phone powers on, it searches for and becomes associated with an AP if the
phone Wireless access is set to On.
The AP uses the connection to the wired network to transmit data and voice packets to and from the
switches and routers. Voice signaling is transmitted to the Cisco Unified Communications Manager
server for call processing and routing.
APs are critical components in a WLAN because they provide the wireless links or "hot spots" to the
network. Cisco requires that the APs supporting voice communications use Cisco IOS Release 12.3(8)JA
or later. Cisco IOS software provides features for managing voice traffic.
In some WLANs, each AP has a wired connection to an Ethernet switch, such as a Cisco Catalyst 3750,
that is configured on a LAN. The switch provides access to gateways and the Cisco Unified
Communications Manager server to support wireless IP telephony.
Some networks contain wired components that support wireless components. The wired components can
comprise switches, routers, and bridges with special modules to enable wireless capability.
For more information about Cisco Unified Wireless Networks, see
http://www.cisco.com/en/US/products/hw/wireless/index.html
Understanding WLAN Standards and Technologies
This section describes the following concepts:
•
•
•
•
Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager 8.6 (SIP)
6-2
shows a typical WLAN topology that enables the wireless transmission of voice for wireless
WLAN with Wireless IP Phones
IP
IP
802.11 Standards for WLAN Communications, page 6-3
World Mode (802.11d), page 6-4
Radio Frequency Ranges, page 6-5
802.11 Data Rates, Tx Power, Ranges, and Decibel Tolerances, page 6-5
Chapter 6
Understanding the VoIP Wireless Network
IP
IP
M