The Call Flow#1 would be better & needed for the scenarios in which SIP UA is configured to receive all its responses through some Inbound proxy server which may provide some security/administrative functions for the SIP UA. In this scenario SIP UA can put the address of Inbound proxy in the maddr parameter.
Regards, Pravesh On 5/31/07, Yong Xin <[EMAIL PROTECTED]> wrote: > Thanks, based on section 18.2.2 of RFC 3261, the INVITE transaction will be > completed like this: > > 1) If Via with "maddr" > > send-by MS maddr > | | | > |----------INVITE --------->| | > | |--------100 -------->| > |<------------------- 100 ------------------------| > | |--------200 -------->| > |<------------------- 200 ------------------------| > |----------ACK ------------>| | > > 2) If Via without "maddr" > > send-by MS > | | > |----------INVITE --------->| > |<--------- 100 ----------->| > |<--------- 200 ------------| > |----------ACK ------------>| > > I'm wondering if there's an use case scenario that call flow #1 is needed > and better than call flow #2. > > Thanks, > Yong > > > -----Original Message----- > From: Sanjay Sinha (sanjsinh) [mailto:[EMAIL PROTECTED] > Sent: Thursday, May 31, 2007 2:26 PM > To: [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: RE: [Sip-implementors] Via header "maddr" parameter question > > Pl. see section 18.2.2 of RFC 3261 about how to send response if there is > maddr param in Via > > >-----Original Message----- > >From: [EMAIL PROTECTED] > >[mailto:[EMAIL PROTECTED] On Behalf Of Yong Xin > >Sent: Thursday, May 31, 2007 3:43 PM > >To: [EMAIL PROTECTED] > >Subject: [Sip-implementors] Via header "maddr" parameter question > > > >Hi, > > > >I'm implementing a Media Server, which is functioning as a SIP UA and > >do nothing about proxy or registration. The implementation is compliant > >to RFC 3261. > > > >Here is an INVITE request received by MS. The request is received from > >source address "10.10.0.1": > > > > INVITE sip:[EMAIL PROTECTED];play=5;repeat=2 SIP/2.0 > > Via:SIP/2.0/UDP > >10.10.0.1:5455;maddr=10.10.0.2;branch=z9hG4bK+222 > > > >As you can see, the Via header also contains "maddr" parameter with a > >different address "10.10.0.2". > > > >1) Which address should be used to send response, "10.10.0.1" > >or "10.10.0.2"? > > > >2) As per RFC 3261 section 18.2.2, address "10.10.0.2" (maddr) should > >be used, but I'm not sure if this rule is applicable for the MS, as the > >MS is a pure SIP UA and does not support multicast. > > > >3) Also, if response is not sent back to source address, what happen to > >the client transaction on the UAC side? Timed-out? > > > >Your comments are appreciated. > > > >Thanks, > >Yong > > > > > >_______________________________________________ > >Sip-implementors mailing list > >[EMAIL PROTECTED] > >https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
