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Walkthrough Wednesdays

CME: Issue with calls from Polycom IP 7000 to IP phone over H.323 VoIP trunk

Hi team,

I have a Polycom IP 7000 registered to Call manager express using SIP. This Call manager express in our branch office is integrated with  Call manager (in central site) via H.323 trunk. The required dial-peers from CME to Call manager have been configured. I am able to call other CME SCCP phones from the IP 7000 and vice versa.

Also, I am able to call the IP 7000 from an IP phone registered to Call manager via H.323. However, I am not able to call an IP phone registered to call manager from the IP 7000 (registered to CME) i.e., when I call an SCCP IP phone registered to Call manager from the IP 7000 (registered to CME using SIP) over the H.323 VoIP trunk, the call is ringing on the Call manager phone, but even if I answer that call on the call manager phone, the call keeps ringing on the IP 7000. The IP 7000 is not detecting that the call has been answered by the call manager phone.

If I use SIP VoIP trunk between CME and CUCM instead of H.323, then calls are working fine between CME phone and CUCM phone in both directions. Attaching the “sh version” and “running-config” of the CME (in cme-ver-runn.txt” file)  and the debugs of “debug ccsip calls’ and “debug cch323 all” collected during call from IP 7000 to CUCM phone (which is not working) in the file ip7000-debugs.txt.

Could you please help me fix this issue? Please let me know if you need more details here.




Hi Swati,

Video calls between Polycom and UCM phones work through a SIP trunk?


- Adrian.


Hello Swati,

My expertise in Video is 0, however looking at the documentation, I think h323 fast start is not supported. Or I am not sure,  you we are running into internetworking limitation in IP-IP Gateway itself.

So I think you are running into a design limitation. As sip eo-h323 ss is also not supported. You can check witht he Video telephony forum.

If Polycom end device supports sccp, configure line side to be sccp(telephony-service ) if not and if it is allowed then change the trunk side to sip and check.




And we cannot disable SIP EO in CME. So we are running out of gas in this setup.


Hi Murali,

I have worked around this issue by configuring in such a way that different outbound dial-peers will be selected for calls from IP 7000 and for other calls between CME and CUCM. The outbound dial-peer related to IP 7000 calls will have "call start fast" and the outbound dial-peer related to other IP phone calls will have "call start fast". So, this fixes our issue.

Thanks a lot for your help here. This issue is now fixed.

Murali, I have actually asked a question related to CME LPCOR in another thread and I did not get any reply. Could you please check once and let me know if you know how to achieve this?



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