Re: [Sip] Re-use of Call-ID in the SIP Replaces header

Jonathan Cumming (jrc@dataconnection.com):

> In section 2.2 of draft-biggs-sip-replaces-01, you specify that "A
> unique call-id may be given to the replacement call.".  This seems
> unnecessarily weak and could lead to interoperability problems where
> an application assumes the re-use of the Call-ID.
> 
> If a unique Call-ID is required, as specified in RFC 2543, then why
> give the end-point the option to re-use the existing Call-ID?

  When we were first discussing methods of performing attended call
transfer, there was alot of discussion about using the Call-ID to
perform the replaces operation, that is, the replacement call (or
joining call) would be identified by having the same Call-ID as an
existing call.

  So, the text should really read "in our replaces model, a unique
call-id may be given to the replacement call, instead of previous models
which overloaded the meaning of the call-id".  I wasn't trying to
dictate behavior either way.

> I suggest that "A unique call-id MUST be given to the replacement
> call".

  Since this seems to be the modern consensus on the issue, I will
clarify this in the draft.

-- 
Billy Biggs                     bbiggs@dumbterm.net
http://www.billybiggs.com/      wbiggs@uwaterloo.ca

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