No Ringback on Outbound Calls via SIP

[justinhulsman]

I am working with a Call Manager Cluster running 8.6.2.  I am testing outbound calls from the Call Manager to an Acme SBC and then out to our provider via SIP trunks.  Our provider is sending a 180 RINGING message with SDP.  There doesn't seem to be any RTP traffic for the ringing, so on our SIP Profile I have the "Disable Early Media on 180" check box checked.

This is the crazy part.  Whenever I reset and restart the SIP Trunks, the outbound call will have ringback.  Any calls after that will not have ringback until the SIP Trunks are reset and restarted once again.  Has anybody seen something like this before?

[brmeade]

Haven't seen that one before.  Have you collected CallManager traces covering the time range of it going from working to nonworking?  Make sure they're set to detailed and enable SIP Stack trace.

Your other option would be to enable PRACK on the SIP Profile so you could just use the early media from the provider if that's more stable for you.

[Selvarathnam Nadar]

Justin,

Is there is gateway router in between, these both call legs.

If it is so, apply "voice call send-alert" in global configuration mode and try.

[justinhulsman]

Instead of a gateway router we have an Acme SBC.  I took Brian's advice and looked at the SIP messaging and nothing was different between the two call-legs.  While testing some more, I noticed that the phone displayed "Ring Out" when the phone had ringback, and did not display anything when there was no ringback.  I think something got hosed up with the SIP Trunk itself to where it didn't know to have the phone play ringback once a 180 was recieved.  I deleted the trunk this morning and rebuilt it just as it was, and I have ringback on every call.  I was using the trunk for testing a new provider as well as a new DSP farm.  I was making quite a few changes quite often and I guess something was hung with all the changes.

Thanks for the feeback, everybody!  I really appreciate everyone's advice.