Having worked heavily with static routing since the pre-release versions of Lync Server 2010 I’ve discovered that while the cmdlet documentation is pretty good on how to create and manage static routes, there is no information on managing static routes in a mixed environment containing both OCS and Lync Server. Recently I had a discussion on this topic with some folks at Microsoft and was able to get some helpful information on the topic.
If you’ve created routes in both OCS and Lync Server you’ve no doubt realized that the process is pretty different. As I referenced in my original post on creating static routes in Lync, Lync enables administrators to create routes with different scopes. Specifically, you can create routes that apply either at the global or registrar level.
Something else apparent as you work in a mixed environment is that Lync is able to use the static routes that have previously been created in OCS but the reverse is not true. Further, a new route added in OCS cannot be leveraged by Lync, and creating the same route in both places leads to routing errors on the OCS side.
The reason for all of this is because of the new mechanisms in Lync for storing and managing static routes. When the Merge Topology process is executed in Topology Builder, the existing OCS routes are copied into the Lync configuration and are therefore able to be used by Lync. New routes created in Lync are only stored in the configuration in such a way as to be accessed by Lync, and since there is effectively no synchronization of configuration from Lync to OCS these routes are not able to be leveraged by OCS.
Therefore, during the period of coexistence the proper way to create routes that you wish to be accessed by both OCS and Lync is to create them in OCS and re-run the Merge Topology process.