SIP dead Air Beginning of the call

[pakman]

I've got several sites A,B,C that could not be ported over to our primary SIP provider. In those instances I'm having the telco provider RFC those numbers to a DID that is our contact center.  Normal call flow would be you call site A it would ring once then play our greeting. Now when you call site A's number there's dead air in the beginning a quick ring more dead air then you hear no digit was selected and our greeting plays. The no digit response happens if you listen to our greeting entirely and don't select anything. Our SIP provider tells me everything looks good on their end and they can see the call connect to our PBX right away. Nothing's changed on my side so I'm not sure what would introduce this dead air. Any tips would be appreciated.

thanks,

[PC77375]

I would continue to press the provider. I had an issue in which voicemail would not answer, company greetings, voicemail, nothing worked and it drove me batty! The carrier fixed it, not sure what the resolution was but I think it had something to do with SDP negotiations. The only thing standard about SIP is that it is not standard. Have you done any packet traces?

[zac1234]

Have you tried capturing traffic on your SBC and listen to the audio?  My guess is that you would hear the recording.  The service provider should also be able to capture the same call from their perspective.  I'm curious to see if the audio is the same in both captures.

I work for a carrier, but I'm in the Mitel group.  We've done this with our SIP support before for audio issues over SIP trunks. 

[PC77375]

Have you tried capturing traffic on your SBC and listen to the audio?  My guess is that you would hear the recording.  The service provider should also be able to capture the same call from their perspective.  I'm curious to see if the audio is the same in both captures.

I work for a carrier, but I'm in the Mitel group.  We've done this with our SIP support before for audio issues over SIP trunks.

And what have you found to be the trouble?


Sent from my iPhone using Tapatalk

[martyn]

This sounds like Early Offer is not being used on the trunk. Does the carrier support Early Offer? A packet capture of the incoming call to the controller would probably provide the answers.