Chapter 6
Understanding the VoIP Wireless Network
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802.11 Standards for WLAN Communications
Wireless LANs must follow the Institute of Electrical and Electronics Engineers (IEEE) 802.11
standards that define the protocols that govern all Ethernet-based wireless traffic. The Cisco Unified IP
Phone supports the following standards:
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Table 6-1
Part Number
CP-9971-K9
802.11j (channels 34, 38, 42, 46) and channel 165 are not supported.
Note
Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager 8.6 (SIP)
Wireless Modulation Technologies, page 6-6
AP, Channel, and Domain Relationships, page 6-7
WLANs and Roaming, page 6-7
802.11a—Uses the 5 GHz band that provides more channels and improved data rates by using
OFDM technology. Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC)
support this standard.
802.11b—Specifies the radio frequency (RF) of 2.4 Ghz for both transmitting and receiving data at
lower data rates (1,2,5.5, 11 Mbps).
802.11d—Enables access points to advertise their currently supported radio channels and transmit
power levels. The 802.11d enabled client then uses that information to determine which channels
and powers to use. The Cisco Unified IP Phone 9971 requires world mode (802.11d) to determine
which channels are legally allowed for any given country. For supported channels, see
Make sure that 802.11d is properly configured on the Cisco IOS Access Points or Cisco Unified
Wireless LAN Controller; for more information, see the
page
6-4.
802.11e—Quality of Service (QoS)
802.11g—Uses the same unlicensed 2.4 Ghz band as 802.11b, but extends the data rates to provide
greater performance by using Orthogonal Frequency Division Multiplexing (OFDM) technology.
OFDM is a physical-layer encoding technology for transmitting signals by using RF.
802.11h—5 GHz spectrum and transmit power management
802.11i—Security
Supported Channels for the Cisco Unified IP Phone 9971
Band Range
2.412 – 2.484 GHz
5.180 – 5.240 GHz
5.260 – 5.320 GHz
5. 500 – 5.700 GHz
5.745 – 5.805 GHz
Understanding WLAN Standards and Technologies
"World Mode (802.11d)" section on
Available
5 GHz Channel
Channels
Set
13 (14 in Japan)
4
UNII-2
4
UNII-2
11
UNII-2 Extended
4
UNII-3
Table
6-1.
6-3