SIP 481 error code

[paolo.gangi]

Hi,

I have a problem of interconnection. During a speech, after the disconnect the call  remains on. Checking the trace I see that when I receive a BYE my gateway answer with a 481 (Call Leg/Transaction Does Not Exist).

[paolo.gangi]

I think the problem is that it changes some paramaters in hte packet like tag but I'm not sure.

[Daniele Giordano]

Please add the pcap file with trace. I think in a modification of BRANCH in the VIA header.

Regards.

[paolo.gangi]

Here is the file.

I agree with your answer

[Daniele Giordano]

In my opinion the problem is in VIA header.
This is the original VIA presents in the outgoing INVITE message: Via: SIP/2.0/UDP  83.211.3.165:5060;x-route-tag="cid:pstn-teles@83.211.3.165"

In your trace the VIA is always the same in every message except in the BYE: Via: SIP/2.0/UDP 81.29.149.10:5060;branch=z9hG4bK-59392848-4e941915; vtbranch=z9hG4bKEX980492;vtservice=routingservice_routingeuro_53.peerservlet+b2buaservlet.siptosip

In a SIP call the Caller-ID is the field to identify a call but the branch header is the filed to identify transaction.

If one of these fileds differ from original is correct having the 481 message as response.

If I correctly understand the call flow, a Cisco sends the call to a VocalTec Essentra B2B agent. Try to investigate the problem in the Essentra.

Regards.