Sending 481 means I don't recognize the dialog but, in the same time I send retransmissions for the same dialog. This looks strange doesn't it ?
When the dialog is terminated ? When first BYE is sent or when BYE transaction is over ?
Amihay
-----Original Message-----
From: Hearty, John [mailto:[EMAIL PROTECTED]]
Sent: Friday, November 15, 2002 5:14 PM
To: Ajit Kalele
Cc: Fuxbruner Amihay; [EMAIL PROTECTED]; Karp Lika
Subject: RE: [Sip-implementors] BYE glare question
Ajit,
I think this is one of the many slightly gray areas in the spec. Because of this, probably a 200 or 481 would be appropriate. Your general assertion seems to be that since the transaction is still there, the session is too by association, and any new requests for that session should be serviced appropriately. This association of the active transaction through the session would be needed to warrant a 200 response to a new request.
This sounds reasonable, but I don't see any text stating such in the RFC. However, there is also no text saying send a 481 in this scenario, hence either response may be appropriate. They would both result in the proper end state at both UAs, i.e. the call is over. I think the important thing is that both UAs send a final response to quench retransmissions. Once the UA at the other end gets it, per the transaction state flow in the RFC the transaction (and call) will be terminated there (after timer K).
John
-----Original Message-----
From: Ajit Kalele [mailto:[EMAIL PROTECTED]]
Sent: Thursday, November 14, 2002 10:37 PM
To: Hearty, John
Cc: Fuxbruner Amihay; [EMAIL PROTECTED]; Karp Lika
Subject: Re: [Sip-implementors] BYE glare question
Hi John,
Certainly the session is terminated a.s.a. a BYE is sent out, but the transaction is still existing (as the UA hasn't received >=200) & it will die only if a final response for BYE is received or t/o occurs.
So a UA can send 200 for the incoming BYE even if it has already sent BYE.
Regards
Ajit
"Hearty, John" wrote:
Couple of things on this. Important rule:Transaction complete independently.Transaction complete independently.Transaction complete independently.So in the flows below, you need a response from B.Section 15.1.1 of RFC3261 has this to say about terminating a session:The UAC MUST
consider the session terminated (and therefore stop sending or
listening for media) as soon as the BYE request is passed to the
client transaction. If the response for the BYE is a 481
(Call/Transaction Does Not Exist) or a 408 (Request Timeout) or no response at all is received for the BYE (that is, a timeout is
returned by the client transaction), the UAC MUST consider the
session and the dialog terminated.The first sentence indicates the session is terminated as soon as the BYE is sent by A, supporting a 481 response to the subsequent BYE received. The next sentence may be somewhat redundant then since the session is already terminated, but was undoubtedly added as clarification that it doesn't matter what you get back, the session is terminated.John HeartyLevel3
-----Original Message-----
From: Ajit Kalele [mailto:[EMAIL PROTECTED]]
Sent: Thursday, November 14, 2002 4:30 AM
To: Fuxbruner Amihay
Cc: [EMAIL PROTECTED]; Karp Lika
Subject: Re: [Sip-implementors] BYE glare question
Both the responses are fine.
If the UA flushes the state machine it can send 481, otherwise it can send 200.
Since the UA hasn't received 200 for BYE it should maintain the state machine and send out a 200/491 for incoming BYE. But even if it doesn't, its not a problem.
Regards
Ajit
Fuxbruner Amihay wrote:
Hi all,
What is the recommended response of A side in the following BYE glare scenario:
A B
BYE ----->
<----- BYE
200 ----->
or
A B
BYE ----->
<----- BYE
481 ----->
Thanks,
Amihay Fuxbruner
System Engineering - Signaling R&D
Comverse
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