Design: Multiple Dest IP ADDR in SIP Trunk vs. Multiple SIP TR in RG?

[Michael Mertens]

We're doing the design for a CUMP 8.5 multi-cluster/multi-region deployment, and are looking at doing the CUCM <-> CUMP integration for the Audio/Video Nodes. Is there any benefit of 1 method vs. the other:

1) Define all the AVN nodes within ONE SIP trunk, each destination IP Addr within the CUCM SIP Trunk config would be the Audio/Video Node, listed in desired order. If the first isn't available, and times-out, then the SIP INVITE would go to the second one, etc...

Or

2) Define a trunk to each AVN node for each cluster (two AVN nodes per cluster), and have the two trunks from each cluster grouped together in their own Route Group, so we'd have three Route Groups in the RL, ordered per their desired priority?

I simply don't know whether the time-out mechanism would be differerent between Route Group members vs. Dest IP Addrseses in the SIP Trunk CUCM Config.

Thanks for any/all input.

Mike.

[Tapan Dutt · Accepted solution]

Second option will give you redundancy because if you go with First Option , In that case Calls will be offered Randomly to Multiple IP's mentioned on the SIP trunk.

Snippet from SRND

Multiple Destination IP Addresses per SIP Trunk

A single SIP trunk can be configured with up to 16 destination IP addresses. Unified CM
uses random distribution to the configured destination IP addresses when placing calls
over a SIP trunk. Using multiple IP addresses on a SIP trunk can help to reduce the need
to deploy multiple trunks with route lists and route groups.

As far as failover of calls is concerned for first option, practically i have never seen CUCM sending a Re-INVITE to an available Live node on the far end once CUCM determines that the call to IP which was extended is down and/or not responding. You can try that in your setup and see if it works.

Tapan