Subject: [Sip] 481 response by a proxy ?

From: "Thalapathy" <[email-masked]>
Date: Mon, 1 Jul 2002 18:29:49 +0200

1)

The SIP RFC2543bis-09 only mentions 481 (call leg/transaction does not exist) as a response generated by a UAS. I donot see any specific mention of this non-2xx response generated by a proxy which had done record-route for receiving mid-dialog requests like re-INVITE.

2)
The SIP RFC2543bis-09 does not seem to discuss the behaviour of a dialog stateful proxy. Does it mean, the handling of mid-dialog requests like re-INVITEs is left to the implementation, in case there is no match found on the dialog context ? Or should the dialog stateful proxy behaviour be same as a UAS, in which case it should generate a 481 response ?

3)

What is the behaviour of a transaction stateful proxy (no dialog states maintained) when it receives a re-INVITE on a secondary server (identified by DNS) because of a primary server reboot. Does it create a new client transaction, forward the re-INVITE to the next hop ? Does it behave statelessly ? The RFC seems to be clear on handling a response recieved at a transaction stateful proxy (which does not contain the response context) by saying that the proxy MUST forward the response by behaving as a stateless proxy.