Specifications

Cisco Unified SIP SRST Feature Overview

Prerequisites for Configuring Cisco Unified SIP SRST

Cisco Unified SIP SRST 4.0 System Administrator Guide

Cisco Unified IP Phone Support

For the most up-to-date information about Cisco Unified IP Phone support, see Cisco Unified SRST 4.0

Supported Firmware, Platforms, Memory, and Voice Products at

http://www.cisco.com/en/US/customer/products/sw/voicesw/ps2169/prod_installation_guide09186a00

805f6f1b.html

Cisco UnifiedIP Phone 7940G and Cisco Unified IP Phone 7960G are fully supported if dual registration

is enabled. Dual registration means that the SIP phone is capable of registering with the main SIP proxy

and the Cisco Unified SIP SRST device (redirect server or back-to-back user agent) at the same time. If

this requirement is not met, the Cisco Unified SIP SRST device may not be capable of routing incoming

calls to the SIP phone until the SIP phone registers with the Cisco Unified SIP SRST device. Cisco

Unified IP Phone 7940G and Cisco Unified IP Phone 7960G,l beginning with phone load

POS3-04-2-00.bin, are capable of dual registration of the phone’s primary phone line. Additional lines

are not registered by the phone for Cisco Unified SIP SRST. To enable dual registration for the primary

line, you must set backup proxy information such as proxy_backup

and proxy_backup_port

in the SIP

phone’s configuration file. For configuration instructions, see the Cisco SIP IP Phone 7960

Administrator Guide, Version 5.1.

Cisco Unified IP Phone 7905G, Cisco Unified IP Phone 7912G, and Cisco Analog Telephone Adaptor

(ATA) 186 are not capable of dual registration; thus they are not supported and have limited functionality

with Cisco Unified SIP SRST.

Platform and Memory Support

For the most up-to-date information about platform and memory support, see the Cisco Unified SRST 4.0

Supported Firmware, Platforms, Memory, and Voice Products at

http://www.cisco.com/en/US/customer/products/sw/voicesw/ps2169/prod_installation_guide09186a00

805f6f1b.html.

Prerequisites for Configuring Cisco Unified SIP SRST

Before configuring Cisco Unified SIP SRST, you must do the following:

• An SRST feature license is required to enable the Cisco Unified SIP SRST feature. Please contact

your account representative if you have further questions.

• Cisco Unified IP Phone 7940G and Cisco IP Phone 7960G are fully supported if dual registration is

enabled. Dual registration means that the SIP phone is capable of registering with the main SIP

proxy and the Cisco Unified SIP SRST device (redirect server or back-to-back user agent) at the

same time. If this requirement is not met, the Cisco Unified SIP SRST device may not be capable of

routing incoming calls to the SIP phone until the SIP phone registers with the Cisco Unified SIP

SRST device. Cisco Unified IP Phone 7940G and Cisco Unified IP Phone 7960G, beginning with

phone load POS3-04-2-00.bin, are capable of dual registration of the phone’s primary phone line.

Additional lines are not registered by the phone for Cisco Unified SIP SRST. To enable dual

registration for the primary line, you must set backup proxy information such as proxy_backup and

proxy_backup_port in the SIP phone’s configuration file. For configuration instructions, see the

Cisco SIP IP Phone 7960 Administrator Guide, Version 5.1.