[Sip-implementors] About ACK request!
y030729 at njupt.edu.cn
Mon Sep 26 21:27:54 EDT 2005
I agree with you after looking up RFC3261 again. There is another question which
is about ACK transaction or even SIP transaction.
Thers is such a sentence in RFC3261: "If the request is INVITE and the final
response is a non-2xx, the transaction also includes an ACK to the response. The
Ack for a 2xx resopnse to an INVITE request is a separate transaction." I agree
with the first part, but, how to make clear the second sentence? Is it a
transaction? But there is no transaction layer for ACK.
BTW, the major function of transaction layer is for retransimition, is it right?
> No transaction for ACK is not exactly true.
> For 3xx~6xx response, ACK request is part of the INVITE transaction.
> For 2xx response, ACK is generate and send by the UAC core, and no
> transaction is created.
> Zhenyu Wu wrote:
> > Hello,
> > We know, there is no transaction for ACK request. But in section 13.1
> > of RFC3261,
> > there is such a statement: "For final responses between 300 and 699,
> > the ACK
> > processing is done in the transaction layer and follows one set of
> > rules (See
> > Section 17). For 2xx responses, the ACK is generated by the UAC core".
> > why the ACK processing is done in the transaction layer, as there is no
> > transaction for ACK request?
> > Thanks,
> > Zhenyu
> > _______________________________________________
> > Sip-implementors mailing list
> > Sip-implementors at cs.columbia.edu
> > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
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