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Georg Kehrer

problem Lync call to 3000MXP with integrated MCU

Dear all

I have the follow Situation on a Customer Site

- VCS-C with V7.02

- 3000MXP with F9.1.1, onyl registered with SIP

- LYNC 2010

Near to all calls are working except If I make a call from 2 LYNC site to MXP (MCU) site and also only if the second call from LYNC, the MXP is ringing but I can not answering the ,call is going broken.

All other Situation are working.

The Problem is I have near to be the same situation in my Office in a Demo labs, and all thing are working.

I'm not the LYNC expert and my Problem is to tell the Customer that should be running without Problem.

Does anybody have an Idea what could be wrong on the LYNC Site?

Any Input very apprecietd.

Thank you

Best Regards


Rising star

Hi Georg,

I don't currently have a 3000 MXP to test with, but I was successfully able to set up a Multisite call from two Lync 2010 clients to a 1700 MXP running F9.1.1 (SIP-only registered) so it's possible that the problems you are experiencing are local to your deployment (e.g not a software bug).

It would probably be best for you to open a TAC case for this as further troubleshooting would require taking logs (Which you shouldn't post on this forum )



Hi Andreas

Thank you for the Feedback.

I have also successfully tested with my 1700MXP in my Office. We are trying to make Trace/Logs but Customer would pay for that, I think the Problem could be on the LYNC site. In this situation we need a huge effort to analyze the situation.

Now, I will see to open a TAC case.

Thank you.

Best Regards


Just out of curiosity, can you call from the MXP endpoint the two different Lync clients?

Is it it a windows computer client or something different?

Did you try to limit the call rate on the VCS to something like 512 per call? (see Links/Pipes under Bandwidth in the VCS config web menu)

I had seen without a lync call can try to allocate 10.000kbit which which might

end up in a 2mbit call on your 3000mxp with no more bandwidth left for the second call.

Just guessing.

I also havent tried the multisite on the mxp endpoint towards lync, but I could picture that

you also have some limitations there regarding codec and bandwidth combinations, ...

Please let us know if and how you fixed it in the end.


Please remember to rate helpful responses and identify

Dear Martin

Thank you for your Input.

Yes, It is possbile call two different Lync Cleints.

and also the Lync client are running on windows.

It was not able to limit the call on the VCS until yet, because I'm still waiting of customer feedback.

I think also we have bandwith Problem, because the 3000MXP has only 1,5Mb not the Bandwith Option with 2mb

But curiosity is, that in my Office with 1700MXP with two Lync client everything is running, also without any bandwith limitation on the VCS.

Now I'm still waiting of the Feedback from Customer, Is it also Possible that something are Configured on the LYNC Server "Call Admission Control", we have this feature configured in our LAB but I have also tested without thema and was also running.

Customer is a little bit frustrate and is now not so easy to communicate with him.

wee will see.

Best Regards



I meet I think the same issue:

Cisco Codec can call 2 lync 2010 clients and do a conference without issue.

If 2 lync 2010 clients call Cisco Codec, and Cisco Codec try to join both call, the first lync video disconnect.

If I disable H239/BFCP on Cisco Codec, if 2 lync client call Cisco Codec, no issue when I join calls but I can't use this workaround.

Note: Cisco codec is registered on VCS 7.X using H323. I'm using B2BUA between VCS and Lync Server 2010.

Did you solve your issue?

Thank you

Best regards

Hi  guilhem.perez

Oh that's a long time ago. I have not works anymore on this project.It was not resolved, customer was so fristarted and have give back the VCS solution.



Hi Guilhem,

You don't mention which codecs your're using, nor which version of the software they're running. 

There were a number of fixes for multi-site capabilities in some of the newer firmware versions (for the MXP at least).

And there's a known bug (CSCud34699) "Duo not opening as expected in multisite scenario (SIP only)" which may or may not be what you're experiencing.

Please remember to rate responses and to mark your question as answered if appropriate.

Please remember to rate responses and to mark your question as answered if appropriate.


thank you both for your answers,

I meet the issue with SX20 et MXP T6000.

Both are registered on VCS using H323 only.

I tried somme firmware versions on SX20 (5.X, 6.2.0, 7.0.2) , T6000 is using version F9.3

I'll try to use SIP instead of H323 to check if the issue is relative to H323.

Best regards

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