Lync Integration with VCS - Option Key required?

[Kim Fitzgerald]

                  We are setting up the lync integration with the VCS on x7.2.  Using B2BUA with lync 2010.  Everything internally is working with the lync configuration, we are only having trouble with external lync participants coming in and we do have edge routers in the mix.  The direct pools are set up as trusted.  We have turn enabled on the expressway.  We are having the calls started from Lync inward.  The VCS sees the calls says it is connected but the call does not establish and then drops normal call clearing. 

My thought for the possible failure is the OCS Collaboration option key has not been added.  But I can't tell in the deployment guide if this key is only need if encryption is taking place.

The other area we are looking at right now on the edge routers is if The Edge server and any firewalls that the Edge server may pass media traffic through may need to be reconfigured to allow RTP over UDP as well as RTP over TCP to be passed.

Can you confirm if the OCS key is a requirement for Lync coming in through the expressway?  And are there other areas that one may recommend why the calls don't fully establish externally.

[awinter2 · Accepted solution]

Hi Kim,

the Enhanced OCS Collaboration option key is indeed required for this call scenario, this is mentioned on pages 13 and 53 in the Lync deployment guide for X7.2:

Calls involving a Microsoft Edge server require the VCS to have the Enhanced OCS Collaboration option key installed, as this key allows for ICE to be used for media connectivity

You are also correct in that you will have to permit RTP UDP traffic to and from your Edge server, as the TURN server on the VCS Expressway currently does not support RTP over TCP. If this is not the case, the ICE connectivity checks between the B2BUA and the Lync client and Edge server will fail, which in turn will cause the call to disconnect.

Hope this helps,

Andreas