We recently removed the OCS R2 Mediation Server from our Lync environment which was the last little bit of backward compatibility kit we had in.
Everything worked pretty well after I had configured the gateway to route calls to the new Lync Mediation Server and visa-versa. One problem that did cause me a significant head-ache however, was the Routing Groups.
For some reason, as soon as I started using the Lync Mediation Server the auto-forwarding of out-of-hours calls would just disconnect…. When making calls in over PSTN to one of the Routing Groups, which was now operating in out-of-hours mode and forwarding calls to a mobile, the call would connect to the RG then immediately disconnect. However, if you dialled the same number from the Lync client it would work without any problems at all ????????
Remove the tick from ‘Enable refer support’ on the Global Trunk Configuration page. This option was disabled by default on OCS R2 but enabled by default on Lync. It seems to cause bedlam with auto-forwarding on Routing Groups for some reason.
Hopefully this will save someone else the time and head-ache it caused me.