Concerning your quote of RFC 3261 481 text, I'm not sure if you are asking
about SUBSCRIBE/NOTIFY 481 or BYE 481 impacts upon dialog and/or associate
usage. If you are asking about SUBSCRIBE/NOTIFY 481 and there is no INVITE
usage, yes the 481 also impacts the dialog since no more usages. If you are
asking about BYE 481 while there is still a SUBSCRIBE usage, no it doesn't
impact the dialog (beyond what may happen to other implementations not
interpreting 481 per RFC 5057).
The following is the snippet discussing 481 ambiguity associate RFC 3261 and
multiple dialog usages.
(8) 481 Call/Transaction Does Not Exist: This response indicates
that the peer has lost its copy of the dialog usage state. The
dialog itself should not be destroyed unless this was the last
usage.
The effects of a 481 on a dialog and its usages are the most
ambiguous of any final response. There are implementations that
have chosen the meaning recommended here, and others that destroy
the entire dialog without regard to the number of outstanding
usages. Going forward with this clarification will allow those
deployed implementations that assumed only the usage was destroyed
to work with a wider number of implementations. Existing
implementations that destroy all other usages in the dialog will
continue to function as they do now, except that peers following
the recommendation will attempt to do things with the other usages
and this element will return 481s for each of them until they are
all gone. However, the necessary clarification to RFC 3261 needs
to make it very clear that the ability to terminate usages
independently from the overall dialog using a 481 is not
justification for designing new applications that count on
multiple usages in a dialog.
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> Sent: Thursday, April 16, 2009 11:12 AM
> To: Brett Tate
> Cc: [email protected]
> Subject: RE: [Sip-implementors] BYE after SUBSCRIBE?
>
> Hi Brett,
>
> I went through that part it says that the dialog shold not be destroyed
> unless it is the last usage of this dialog,but in case of a non-invite
> subscription ,the subscription itself is the last and the only usage
> so,will the subscription not be terminated?
>
>
> Thanks and regards,
>
> Shamik Saha
> Project Engineer
> Voice Protocols
> Cell : +91-9886704155
>
> -----Original Message-----
> From: Brett Tate [mailto:[email protected]]
> Sent: Thursday, April 16, 2009 8:33 PM
> To: Shamik Saha (WT01 - Telecom Equipment)
> Cc: [email protected]
> Subject: RE: [Sip-implementors] BYE after SUBSCRIBE?
>
> The RFC ambiguity is discussed within RFC 5057; search for 481.
>
> The most relevant text is within section 5.1 note 8 concerning 481.
>
> > -----Original Message-----
> > From: [email protected] [mailto:[email protected]]
> > Sent: Thursday, April 16, 2009 10:58 AM
> > To: [email protected]
> > Cc: [email protected]; Brett Tate;
> > [email protected]
> > Subject: RE: [Sip-implementors] BYE after SUBSCRIBE?
> >
> > But section 12 of RFC3261 says that if a 481 response is received
> > within a dialogue then the dialoue will be terminated
> >
> > " If the response for a request within a dialog is a 481
> > (Call/Transaction Does Not Exist) or a 408 (Request Timeout), the
> UAC
> > SHOULD terminate the dialog."
> >
> > So essentially the subscription state at the subscriber end will also
> > be removed.
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