atcomsystems.ca/forum Forums TDM Business Telephone Systems Avaya - Lucent Telephones & Systems Phone system could not release SIP trunks when twinning

Another half day there, we setup wireshark to trace the SIP calls going out/into the phone system.

When SIP trunks were not released, phone system did not receive a BYE request. when we hung up from handset, phone system send a BYE request, but SIP server send back an error 481: Call/Transaction Does Not Exist.

It looks SIP server did not send a BYE request, or phone system did not receive it because of network issue.