When you trying to call from Cluster A to Cluster B with publisher shut down in cluster A, then the SIP Invite message are sent with SUB IP address and this same SUB address must be present in the SRV destination IP address of Cluster B Trunk configuration.
Since it's provide a security feature where the receiving cluster won't accept any call if the sending IP adddress is not present in its configuration.
You must be getting error 503 service not available when you dialling from Cluster A.
This error send by CUCM (or gateway) only when the IP address is not recognized by the receiving CUCM.
so please put the all IP address of the cluster (pub & sub) in the trunk configuration.
If it was SIP Trunk then it would had given you RUN ON ALL MODE ACTIVE option to enable it.
We have already defined all IP address of CUCM from Cluster B on the ICT registered from Cluster A. When we shutdown one CUCM from Cluster B; failover, then try another call we are getting fast busy tone.
And we have also observed that if we dial other route pattern that going to ICT, the call was successful.
Here is the Snippet from CUCM 8.x SRND about SIP Trunk preference.
General Deployment Considerations
Unified CM SIP trunks offer a greater set of features in comparison with H.323 intercluster trunks, thus making SIP the protocol of choice for intercluster trunk connections (although H.323 Annex M1 may still be preferred for intercluster trunk connections to Unified CM clusters using earlier software versions). Also, given the wide support of SIP in the industry, SIP trunks are usually a good choice for connectivity to third-party applications and service providers.
While H.323 trunks are still supported, SIP trunks are the recommended trunk type for Unified Communication deployments because SIP trunks provide additional features and functionality not available with H.323 trunks.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...
If you have 2 ISR routers, one acting as Failover, do we need to have both the same number of SRST licenses on the 2 routers?
No. You will only need the SRST licenses on the primary router. Because this feature...
You have reached the Cisco Logistics Support Center.. To Check Status of your RMA, visit Product Returns & Replacements (RMA).
Need help? Contact us by Phone or Email.
Phone: 1800 553 2447 Option 4