OCS 2007R2 - 3 party conference calls

[tscht28]

I have a problem whenever we attempt to place conference calls between two Microsoft Enterprise Voice users (communicator softphone users) and an external number (Cell phone/Landline) the external callee answers the call, but then the callee is immediately dropped.  All other features with our Mitel integration work without any problems.  We are using 10.0.3.30 on our Mitel and our OCS build is OCS 2007 R2 CU6.

[tscht28]

Update:  While researching this problem, I came across a document that talked about enabling the DPNSS feature called:  EARLY_TX_CHAN_CONN.  Our feature was disabled and after enabling it, 3 party conference calling capabilities went from 0 percent completion to between 33 & 50 percent completion.  This feature also fixed MOH issue between our Mitel Desk phone and MS communicator soft phones.   Definitely a step in the right direction, but still need help bumping up our 3 party call percentage rate.

[martyn]

You don't mention it, but I am assuming that you are using SIP trunks between the MCD and the Lync mediation server. Have you followed the guide that was posted on MOL for integration, or are you trying it from scratch?

It might pay to grab some SIP traces from the MCD to see if there are any hints in that as to why the calls might drop. Post them here if you can't decipher them and we might be able to help. 

[tscht28]

I have followed the guide and I have tried tweaking the form options in the SIP Peer Profile without any luck.  I have done traces from the MS OCS environment, but not from the MCD, do you recommend a specific SIP trace?  The error I receive on the MS OCS side is 486 Busy Here.