Hi; Yes I totally agree with you, I just saying that I saw several SIP elements that do not add Via headers in ACK. Those elements may be using the old SIP RFC 2543 way of identifying a transaction, not just using the via branch parameter.
Regards Diego B Singh, Indresh (SNL US) wrote: > As per table-3 of RFC-3261 Page 163. ACK must have via. > > Via header carries minimum two information. > One is the address where the response should be sent. > The second is the branch identifier which is used to identify > transaction at the peer element ( UAS/Proxy ) > > So I think the SIP elements which would not include via in the ACK, they > are incorrect. For e.g consider the INVITE-3XX case. Here UAS is > waiting for an ACK with a via header carrying the same branch as in > INVITE-3xx to stop transaction retransmission timers. Without a via > header the transactions can not be identified and transaction > retransmission timers can not be stopped. > > > Regards, > > Indresh K Singh > ------------------------------------------------------------- > Sr. Software Engineer > SIP Media Control and Signaling > Nokia Siemens Networks > Boca Raton, FL-33487 > Ph: 561-923-5085 (o), 561-923-2048 (o) > ------------------------------------------------------------- > > > > >>> -----Original Message----- >>> From: [EMAIL PROTECTED] >>> [mailto:[EMAIL PROTECTED] On Behalf >>> Of ext Diego B >>> Sent: Saturday, May 19, 2007 12:59 AM >>> To: [EMAIL PROTECTED] >>> Cc: Sip-implementors@cs.columbia.edu >>> Subject: Re: [Sip-implementors] Is the VIA header mandatory >>> in all request messages >>> >>> Hi; >>> For example the ACK request. >>> I saw several SIP elements that sends ACK without a Via header. >>> >>> [EMAIL PROTECTED] wrote: >>> >>>> From: "Rami Eitan" <[EMAIL PROTECTED]> >>>> >>>> My question is does anyone know of or has ever come across a >>>> request message without the VIA header in it? >>>> >>>> If there was no Via header, the recipient would have no way to know >>>> where to send the response. >>>> >>>> Dale >>>> _______________________________________________ >>>> Sip-implementors mailing list >>>> Sip-implementors@cs.columbia.edu >>>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >>>> >>>> >>> _______________________________________________ >>> Sip-implementors mailing list >>> Sip-implementors@cs.columbia.edu >>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >>> >>> _______________________________________________ Sip-implementors mailing list Sip-implementors@cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
