Comments inline...

Thanks & Regards,
Nataraju A.B.

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bob
Penfield
Sent: Tuesday, April 04, 2006 7:55 PM
To: [EMAIL PROTECTED]; 'Sigrid Thijs';
[email protected]
Subject: Re: [Sip-implementors] Forking: early dialog termination

It is not necessary for a UAC to cleanup other early dialogs (i.e. send 
BYEs) when it receives a 2xx. The forking proxy would have issued a
CANCEL 
to all the other UASs in attempt to prevent them from completing the
INVITE. 
Those UAS's would send a 487 response to the INVITE which would stop at
the 
forking proxy. Any BYEs to those UASes would likely get a 481 response.

If any of the early dialogs were not successfully terminated, the UAC
would 
see a 2xx, which it could BYE at that time.

Sending a BYE on other early dialogs would only inject unnecessary
messages 
into the network.

[ABN] I feel this is required. Assume the scenario where in call is
terminated @ UAS_1 and UAS_2...


UAC             Proxy           UAS_1   UAS_2

|------INV------>|------INV----->|
                  |---------------INV------------->|
|<-------180-----|<-----180------|
|<-------180-----|<-----180----------------------|
|<-------200-----|<-----200------|
                    |---------------CNCL---------->|
                    |<--------------200-CNCL------|
                    |<--------------487-INV--------|
                    |---------------ACK------------>|

in this scenario, the early dialog form UAS_2 will persists for the
complete call if the UAC did not cleanup the early dialog soon after it
had got the final response on one of the dialog. In most of the cases
you can expect 481 on these BYE requests to terminate the early dialogs.

cheers,
(-:bob

Robert F. Penfield
Chief Software Architect
Acme Packet, Inc.
71 Third Avenue
Burlington, MA 01803
[EMAIL PROTECTED]

----- Original Message ----- 
From: "Manjunath Warad" <[EMAIL PROTECTED]>
To: "'Sigrid Thijs'" <[EMAIL PROTECTED]>; 
<[email protected]>
Sent: Tuesday, April 04, 2006 7:50 AM
Subject: Re: [Sip-implementors] Forking: early dialog termination


> Hi,
> I am really sorry, I took the question in a different meaning.
>
> Since a UAC can potentially reach multiple hosts using the same INVITE
and
> therefore multiple calls can be created. Which one it accepts and
which 
> ones
> it dosen't is its own decision. If early dialogs are created and a 2xx
is
> received on one of them, then the UAC
>
> (1) Can wait for an implementation defined "Ringing Timer" (the time
it
> allows the terminal to ring after getting a 1xx). Maybe 64*T1 for 2xx
> responses on other dialogs, in case it decides not to finalize the
dialog 
> on
> which the 2xx was first received.
>
> (2) Can terminate the Dialog immediately after getting a 2xx by
sending a
> BYE implying the first 2xx received was finalized.
>
> Either ways, I feel the UAC SHOULD send a BYE to clean up the Peer
Network
> early dialogs gracefully which have nbot been responded at the time of
> making the cleanup decision.
>
> Rgds,
> Manju
>
>
>
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> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Sigrid 
> Thijs
> Sent: Tuesday, April 04, 2006 3:53 PM
> To: [email protected]
> Subject: [Sip-implementors] Forking: early dialog termination
>
>
> Hi,
>
> I'm sorry if this has been asked before, but I haven't found a real
> answer to this question.
> According to RFC 3261:
>
>   If the forwarded response was a final response, the proxy MUST
>   generate a CANCEL request for all pending client transactions
>   associated with this response context.
>
> What is the desired behavior for the UAC?
> - non-2xx response: all early dialogs are considered terminated
> - 2xx response: early dialogs are terminated 64*T1 seconds after the
> reception of the first 2xx response
>
> Does the UAC need to terminate these early dialogs by sending a BYE
> request, or should it just discard the early dialogs?
>
> -- 
> kind regards,
> Sigrid Thijs
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