Hello,
What would cause the following errors:
2012.08.09 08:21:42 TM.T02 0 IsdnTrunkManager::getIsdnChannel - TA = 19, IsdnChannel is NULL
2012.08.09 08:21:42 TM.T02 20 IsdnTmStateIdling - clear trunk appearance
2012.08.09 08:21:42 SB.CALL 178033 RTP resource unavailable or SDP negotiation failed. Call from (XXXXXXXXXX) to (XXXXXXXXXX).
These errors happened while the call was coming out the PRI routing to a VoIP gateway.
This call never reach the VoIP gateway (verified by a packet trace that I keep running).
Any help will be greatly appreciated.
Thank you,
Unified,
We may have a B channel allocation or resource issue of some kind. I would first verify that both sides of the PRI are set to use the same number of B channels. If you set the resource selection to circular, can you determine if the failures only occur when specific B channels are requested? We would likely need to see the following debug output for a given test call.
debug voice verbose
debug isdn L2-formatted
debug sip stack message
Thanks!
David
Hi David,
I have thousands of calls going through the 644 daily.
This only happened once.
unified,
With that call volume, we bring in the possibility both systems trying to access the same B channel at the same time. This is typically called glare. The best prevention is to make sure that each device prefers a different end of the B channels. In Adtran CLI syntax, this would be "resource-selection linear ascending" on one unit and "resource-selection linear descending" on the other side of the PRI. Given this configuration, the potential for glare really only exists when there is only one free B channel.
If you get a complete debug capture, we would be glad to take a closer look.
Thanks,
David
This is only being used for inbound traffic (from PRI to SIP) so I doubt it will a glare issue.
Since It only happened once my guess is that it was a fluke.
unified,
I'm going to go ahead and mark this post as "assumed answered". However, if you continue to have any problems we would be glad to take a closer look at debug output. Just let us know if we can help out.
Thanks!
David