Sourav, Please note the tile of Sec 9.1 is Client Behavior, "Client" here is not just UAC, stateful proxy is applied here as well. Proxy can send CANCEL on its own (sec 16.7 Response Processing item 10), the invite it intends to cancel might have multiple Vias, but the CANCEL itself only has one Via. FYI -Rockson ________________________________
From: Sourav Dhar Chaudhuri [mailto:[EMAIL PROTECTED] Sent: Thursday, September 18, 2008 3:44 PM To: Rockson Li (zhengyli) Cc: [email protected] Subject: Re: [Sip-implementors] Can multiple Via header be present in initialINVITE request ? Hi Rockson, Thanks for your reply. By my doubt come from other scenario.like for CANCEL request RFC 3261 specifies under said line for Via header Sec 9.1 A CANCEL constructed by a client MUST have only a single Via header field value matching the top Via value in the request being cancelled. So here RFC used the word "single" before "Via header" which is not present in the line you mentioned in Sec 8 of RFC 3261 And another part it is saying that "top Via value in the request being cancelled." which it seems like request can contain multiple "Via header" value in initial INVITE request among which top "Via header" value has to be selected Thanks Sourav ----- Original Message ---- From: Rockson Li (zhengyli) <[EMAIL PROTECTED]> To: Sourav Dhar Chaudhuri <[EMAIL PROTECTED]>; [email protected] Sent: Thursday, 18 September, 2008 12:43:16 PM Subject: RE: [Sip-implementors] Can multiple Via header be present in initialINVITE request ? I think the answer is "no". RFC3261 mandates UAC only insert a Via header when sending request. Sec 8 When the UAC creates a request, it MUST insert a Via into that request. And respnse with multiple Via would be rejected by UAC. Sec 8.1.3.3 If more than one Via header field value is present in a response, the UAC SHOULD discard the message. The presence of additional Via header field values that precede the originator of the request suggests that the message was misrouted or possibly corrupted. FYI -Rockson -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Sourav Dhar Chaudhuri Sent: Thursday, September 18, 2008 3:05 PM To: [email protected] Subject: [Sip-implementors] Can multiple Via header be present in initialINVITE request ? Hi, Can multiple Via header be present in initial INVITE request ? I mean to say when first time INVITE request is generated from UAC without traversing any PROXY can contain multiple Via header ? If yes then what is the need of having multiple Via header in initial INVITE request? Thanks Sourav Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/ _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors ________________________________ Check out the all-new face of Yahoo! India. Click here. <http://in.rd.yahoo.com/tagline_frontpage_1/*http://in.yahoo.com/?wm=n/> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
