Subject: Re: [sipcore] Does a forking proxy send 481?

From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Mon, 3 Jan 2011 12:53:47 -0500

________________________________________
From: [email-masked] [[email-masked]] On Behalf Of Christer Holmberg [[email-masked]]

Question: Does the forking proxy send a 481 response to the request, or does it forward it towards the remote UAS previously associated with ED1?

The reason I ask is because of a question whether there should always be a 2xx response to a PRACK, even if the associated dialog has been terminated. But, a proxy that does not know PRACK would of course send a 481.
_______________________________________________

It appears that the forking proxy has the option of sending 481 in response to a request directed to a dialog that it knows has terminated.  It seems that PRACK is an exception to this, but as you note, the proxy may not understand PRACK.  The safest implementation is that the UA should be prepared to receive a 481 response to the PRACK.

Dale