Call ID based persistence for SIP sessions
We are using the F5 LTM for load balancing SIP traffic and we would like to use Call Id based persistence to make sure all SIP messages with the same call Id go to the same server. However we noticed that the persisteance is really based on the combination of call-Id+source IP address and not call-ID alone. How do we make it based on call-ID alone?
This is the scenario: there are 2 end-points X and Y that are sending SIP messages to the LTM for the same call-ID. The load balanced backend pool has 2 servers A and B. What I am noticing is that even though the call-ID in the SIP messages is the same some SIP messages go to A and others go to B just because the source was different (X vs Y).