Cisco UCM + CUE integration - in SRST scenario

In previous post I have highlighted the steps and procedures that are required for a UCM + CUE JTAPI integration:

http://pandaeatsbamboo.blogspot.com/2012/02/ucm-cue-integration-example-step-by.html

What if the CUE is located at a branch site and the connection between UCM and CUE is broken?  When the WAN link is downed, SRST kicks in and the CUE can change from a JTAPI integration into a SIP integration, so that the SRST router can talk to CUE via SIP.

0. Assume you have the JTAPI integration in place, for normal situation when the connection between hub site and branch is up:
http://pandaeatsbamboo.blogspot.com/2012/02/ucm-cue-integration-example-step-by.html

1. Configure CUE SIP subsystem, the gateway address is your SRST router address:

ccn subsystem sip

gateway address "192.168.166.254"

mwi sip unsolicited

2. Configure SIP trigger, the voicemail pilot number:

ccn trigger sip phonenumber 1110

application "voicemail"

3. Configure the SIP dial-peer on your router

dial-peer voice 1110 voip

destination-pattern ^1110$

session protocol sipv2

session target ipv4:192.168.166.254

dtmf-relay sip-notify

codec g711ulaw

4. Configure the SIP MWI:

sip-ua

mwi-server ipv4:142.1.66.253 expires 3600 port 5060 transport udp unsolicited

5.  Sample CME as SRST configuration

telephony-service

srst mode auto-provision none

srst ephone template 1

srst dn template 1

srst dn line-mode octo

max-ephones 20

max-dn 20 no-reg

ip source-address 192.168.166.254 port 2000

voicemail 1110

mwi relay

max-conferences 8 gain -6

transfer-system full-consult

create cnf-files version-stamp 7960 Feb 25 2012 01:03:36

!

!

ephone-dn-template  1

call-forward busy 1110

call-forward noan 1110 timeout 20

mwi sip

huntstop channel 1

!

When the WAN link is downed, your branch phone can still access your local CUE, leave and retrieve voicemail as usual and the end user experience, MWI, etc will be the same.