Specifications

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Cisco Unified Wireless IP Phone 7921G Administration Guide for Cisco Unified CallManager Release 4.1, 4.2, 5.0
OL-10802-02
Chapter 2 An Overview of the Voice Over IP Wireless Network
Components of the VoIP Wireless Network
Transmission Control
Protocol (TCP)
Connection-oriented transport
protocol.
Cisco Unified IP Phones use TCP to
connect to Cisco
Unified
CallManager and to access
XML services.
Trivial File Transfer
Protocol (TFTP)
Method for transferring files over the
network.
On the Cisco Unified IP Phone,
TFTP enables you to obtain a
configuration file specific to the
phone type.
You must have a TFTP server in your
network that the DHCP server
automatically identifies. If more than
one TFTP server is running in your
network, you must manually assign a
TFTP server to each phone.
Transport Layer
Security (TLS)
TLS is a standard protocol for
securing and authenticating
communications.
When security is implemented, Cisco
Unified
IP Phones use the TLS
protocol when securely registering
with Cisco Unified
CallManager.
Unscheduled
Asynchronous Power
Save Delivery
(U-APSD)
Allows the phone to be in power save
mode yet receive queued packets
from AP.
When the Cisco Unified Wireless
IP
Phone 7921G can use U-APSD,
battery life is substantially improved.
User Datagram Protocol
(UDP)
Connectionless messaging protocol
for delivery of data packets.
Cisco Unified IP Phones receive and
process UDP messages. RTP voice
traffic runs over UDP.
Wi-Fi (802.11) An open standard that defines
wireless methods of transmitting
Ethernet traffic and is commonly
called Wi-Fi. This standard defines
radio frequencies (RF) and data
speed for wireless LAN
communications.
Cisco Unified Wireless
IP
Phone 7921G supports the Wi-Fi
standards. See
Table 2-1 for more
information.
Table 2-3 Supported Networking Protocols on the Cisco Unified Wireless IP Phone 7921G
Networking Protocol Purpose Usage Notes