thnx for ur response vijay..
i understand that the rule for processing request
mandates the insertion of Via..
but is it just for sake of the rule that we need the
via in ACK.. wherein in other places via makes sense..
and is needed..
is it fair to say that we necessarily dont need the
via: in ACK for proper functioning..(assuming the
server does'nt crib about the missing via: in ACK)
rama
--- Vijay Gurbani <[EMAIL PROTECTED]> wrote:
> Ramachandran Iyer wrote:
> >
> > hi,
> >
> > as we know that
> >
> > Via is always used to forward responses.
> > Route is always used to determine where to forward
> > requests
> >
> > Also let us consider a typical call flow..assume
> two
> > intermediate proxies..( A-->p1-->p2-->B)
> >
> > INVITE -- RecordRoute: p2,p1
> > 200 (invite) -- RecordRoute: p2,p1
> > ACK -- Route : p2,b
> > BYE -- Route : p1,b
> > 200 (bye)
> > ---------------------------------------------
> >
> > Now my query is what is the need for the Via: list
> > being built up for ACK as it traverses from
> > (A-->p1-->p2-->B)as Via: is used by responses to
> trace
> > back the path, but ACK does not generate any
> > responses.
> [...]
> > In a Nut-shell is it fair to say that the Route
> for
> > subsequent transaction is known to both client and
> > server upon the receiving of a 200 from B-->A.
> (when B
> > relays it through the record-route).
>
> Yes; the UAS can build the route set on receiving
> the INVITE (and generating
> a 200 OK, of course), and the UAC can build the
> route set on receiving the
> 200 OK. Once the route set has been built,
> subsequent requests, including
> ACK, will follow it.
>
> Even though ACK does not generate a response, any
> intermediate SIP entities
> processing it have to follow the rules of processing
> requests, including
> inserting a Via.
>
> Regards,
>
> - vijay
> --
> Vijay K. Gurbani
> vkg@{lucent.com,research.bell-labs.com,acm.org}
> Internet Software and eServices Group
> Lucent Technologies/Bell Labs Innovations 263 Shuman
> Blvd., Rm 1A-413
> Naperville, Illinois 60566 Voice: +1 630 224
> 0216 Fax: +1 630 713 0184
> _______________________________________________
> Sip-implementors mailing list
> [EMAIL PROTECTED]
>
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
__________________________________________________
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/
_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
