11-27-2012 08:56 AM - edited 03-16-2019 02:25 PM
Hi there,
We have Cucm 8.5 over several sites using local gateways to PSTN calls. On a gateway connected to CUCM over a SIP trunk and then connected to provider through another SIP trunk, we get an initial delay of 0.5 - 2s on an outbound call (usually initial "Hello?" is missed or first few words of a recorded message). Then the call proceeds without any problems - no delay, no drop offs.
At sites where we have a gateway connected to CUCM via H.323 and then ISDN link to PSTN, or QSIG to a legacy PBX, this delay doesn't happen.
I've tried to check "Disable early media on 180" for the internal SIP trunk profile, which I think helped a bit, but there is still a short delay. Any thoughts?
Thanks
11-27-2012 12:55 PM
Questions:
If you don't know the answers for the first two questions please enable 'debug ccsip messages' and post an example of the problem.
Also, please post a copy of your dial-peers from the router.
11-28-2012 06:09 AM
Thanks.
I've fixed the problem by checking the following 2 (seemingly contradictory) options on the SIP trunk between CUCM and the CUBE:
1. Disable Early Media on 180
2. Send PRACK if 1xx contains SDP
No delay any more for outbound calls, but why these settings work I don't know.
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