We use Ken's Skypeoptimzer site to create our dialing rules. we've used failover routing in the same site for this.
unfortunately an unintended result is: any external inbound call to one of our users which has simring enabled, results in the sim ring leg of the call going out via our second SIP trunk and not through the same trunk as the inbound call. this becomes an issue since our Secondary 'failover' trunk is infact a pstn gateway which cannot pass the original calling parties call id on the outbound call id of the simring portion of the call.
we do have an sbc which we can add the pstn gateway to (the same one which controls the primary SIP Trunk), the issue is this would introduce a single point of failure into the call path.
has anyone successfully managed to deal with this issue?