Audio delay when call is answered, CUCM 8.0

[gmgarrian]

I have a client who is reporting an audio delay when a call is made to an external number. Call setup is fine and ringing begins immediately after the last digit is dialed.  When the called party answers there's a 1 or 2 second delay before either party can hear each other.

Outbound calls are routed to a SIP trunk.  I am suspecting that an MTP is required but checking that off causes all calls to fail. 

I then discovered that the only MTP defined in CUCM is the default and this is in a different device pool than the SIP trunk with the delay issue.

Before I got through a possilbe hardware purchase (router, dsps, etc.) for the site with the problem I was hoping someone could confirm that this may in fact be the issue.

Thoughts?

[George Thomas]

Under the SIP Profile, change the "SIP Rel 1XX Options" to "Send PRACK if 1XX Contains SDP". This will cut the audio through right away. If Default profile is used by other SIP trunks, i would recommend creating a new profile and assigning this profile to the trunk to the gateway.

[gmgarrian]

I don't see that option under the SIP profile. It turns out that it's running CUCM CUCM 7.1.3.30000-1.  Any other ideas?

[jasyoung]

Under older versions of CUCM, you can set that same parameter as a global Service Parameter for the CallManager process.You can try that. Newer versions pushed the setting down to the individual trunk level. Be aware the global setting will affect all calls on all SIP trunks, so test carefully after the change.

[gmgarrian]

Thanks for the info.  I'll give it a try and let you know.