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Cisco Unified IP Phone 7960G and 7940G Administration Guide for Release 8.0 (SIP)
OL-7890-01
Chapter 1 Product Overview
BTXML Support
SIP Clients
SIP clients include the following:
•
Phones
Phones act as either a UAS or a UAC. Softphones (PCs that have phone capabilities installed) and
Cisco SIP IP phones can initiate SIP requests and respond to requests.
•
Gateways
Gateways provide call control. Gateways provide many services, the most common being a
translation function between SIP conferencing endpoints and other terminal types. This function
includes translation between transmission formats and between communications procedures. In
addition, the gateway also translates between audio and video codecs and performs call setup and
clearing on both the LAN side and the switched-circuit side.
SIP Servers
SIP servers include the following:
•
Proxy server
A proxy server receives SIP client messages and forwards them to the next SIP server in the network.
Proxy servers can provide functions such as authentication, authorization, network access control,
routing, reliable request retransmission, and security.
•
Redirect server
A redirect server receives SIP requests, strips out the address in the request, checks its address tables
for any other addresses that may be mapped to the one in the request, and then returns the results of
the address mapping to the client. Basically, redirect servers provide the client with information
about the next hop or hops that a message should take, and then the client contacts the next-hop
server or UAS directly. Location services are often included with redirect servers and provide
contact information and address bindings for called parties.
•
Registrar server
A registrar server processes requests from UACs for registration of their current location. Registrar
servers are often colocated with a redirect or proxy server.
BTXML Support
The Cisco SIP IP phone supports Basic Telephony eXtensible Markup Language. BTXML defines XML
elements for controlling the user interface of an IP telephone. It describes what information is displayed
on the screen and how to provide input using softkeys and hard keys. User-interface control is internal
to the phone; there is no external BTXML user interface control.
Cisco IP Phone Services
The Cisco SIP IP phone supports Cisco IP Phone Services that you configure to provide data such as
stock quotes, calendars, and directory lookups. Phone users access this information using phone buttons
such as the Services or Directories buttons. See
Chapter 4, “Managing Cisco SIP IP Phones,”
for
information about configuring these cards.