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Anonymous
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Trunk errors on the NetVanta 644

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,

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5 Replies
Anonymous
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Re: Trunk errors on the NetVanta 644

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

Anonymous
Not applicable

Re: Trunk errors on the NetVanta 644

Hi David,

I have thousands of calls going through the 644 daily.

This only happened once.

Anonymous
Not applicable

Re: Trunk errors on the NetVanta 644

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

Anonymous
Not applicable

Re: Trunk errors on the NetVanta 644

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.

Anonymous
Not applicable

Re: Trunk errors on the NetVanta 644

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