OK, so you think the Associated Gateway list is a failover pair so that the top of the list is the primary, and in the event of an OPTIONs failure the second gateway is tried ...and so on down the list. This means I don't have the opportunity to outbound load balance my traffic.
I would assume that in the scenario when I reach my concurrnet call limit on the trunk, the OPTIONS responses will still be 200 OK so calls will still be routed down the primary trunk but rejected due to the call limit. In this scenario is Lync clever enough to try the second trunk? I don't know enough about SIP failure codes to know if there is a sensible failure code Lync could act up on inthis scenario.
What I would ideally like to happen is for the calls to overflow into the second SIP trunk. Hmm, I suppose CAC can't be used here can it ... maybe I could split the two SEs into seperate sites and CAC into the second site when the limit is reached.
As for real resilience, in this scenario GC provide the IP VPN and we have specced dual POPs so in theory we should have full resilience .... it's just the SBC and gateway end that needs to be specced up as resilient.
Jed
