Hi, I think it is a MUST for 18x message to have a Contact header if it requires 100rel. 18x MUST establish a dialog (early), over which PRACK request will be sent. Contact header MUST be included in the response to establish a dialog.
PRACK is handled as any non-INVITE request. Therefore, UAC will retransmit PRACK until it receives a response when it uses unreliable transport like UDP. Otherwise, when it uses reliable transport like TCP, UAC will not retransmit PRACK following the rules for non-INVITE client transaction described in RFC 3261. Note that UAC does not have to retransmit PRACK when it receives retransmission of 18x responses. Regards, Takuya > > Hi Kasam, > > No it is not mandatory to have the contact header in 18X when it > requires 100rel. > > Yes it is MUST to retransmit a PRACK until you get a response for PRACK. > > Prack should be handled as any non-invite request. > > > HTH, > > Regards, > SReeram > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Kasammiya > Patil > Sent: Tuesday, June 22, 2004 2:13 AM > To: [EMAIL PROTECTED] > Subject: [Sip-implementors] Question on 18x and PRACK > > > Hi all, > > Is it a MUST for 18x message to have Contact header if it > requires 100rel ? > > Is it a MUST to retransmit a PRACK ? > > Kasam Patil > CS2K SIP Design and Development > ESN: 351 8346 External: 919 991 8346 > Yahoo ID: kasampatil > > > > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > -------- Takuya Sawada KDDI Corporation (KDDI) Garden Air Tower, 3-10-10, Iidabashi, Chiyoda-ku, Tokyo 102-8460, Japan Tel: +81-3-6678-2997 Fax: +81-3-6678-0286 [EMAIL PROTECTED] _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
