> From: Iñaki Baz Castillo [[email protected]]
> 
> Hi, imagine a Proxy which first receives a 480 response and forwards
> it upstream to the UAC (and receives the ACK) but later, for some
> annoying reason, the Proxy receives a 200 for the same client
> transaction.

E.g., a proxy sends the INVITE to UA 1.  UA 1's 200 response and
retransmissions thereof are lost by the network for a while.  The
proxy gives up on UA 1, synthesizing a 408 response for it, and sends
the INVITE to UA 2, which gives a 480 response.  Then the network
starts working, and UA 1's next 200 resend arrives at the proxy.

> Should the client discard it? or should it route it? (let's assume
> that it occurs in the same second so the transaction still is in
> memory, but in "completed" state.

The 200 must get an ACK, and (assuming we think the dialog is
hopeless), a BYE should be sent to terminate the dialog.  The proxy
could do this, but I think it's more in the spirit of 6026 to forward
it upstream and let the UAC terminate the dialog as part of the usual
"cleaning up stray dialogs" processing.

Dale

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