Typically a REGISTER request doesn't not establish a dialog. RFC 3261 section 10.2.
" A REGISTER request does not establish a dialog. A UAC MAY include a Route header field in a REGISTER request based on a pre-existing route set as described in Section 8.1. The Record-Route header field" Also from Section 8.1.1.2 A request outside of a dialog MUST NOT contain a To tag; the tag in the To field of a request identifies the peer of the dialog. Since no dialog is established, no tag is present. So, there is no need for a To tag in REGISTER. In order to have better interoperability, the presence of To tag should be ignored. Thanks, Neel. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bob Penfield Sent: Friday, November 21, 2008 8:29 AM To: Rockson Li (zhengyli); Tarun2 Gupta; [email protected] Subject: Re: [Sip-implementors] Query regarding 'To' tag in REGISTER request A request should only have a To tag if it is an in-dialog request. REGISTER is not part of a dialog. A REGISTER request never has a To tag. ________________________________________ From: [EMAIL PROTECTED] [EMAIL PROTECTED] On Behalf Of Rockson Li (zhengyli) [EMAIL PROTECTED] Sent: Friday, November 21, 2008 12:15 AM To: Tarun2 Gupta; [email protected] Subject: Re: [Sip-implementors] Query regarding 'To' tag in REGISTER request IMO, to tag is meaningless for REGISTER request, it's not necessary to add to tag in REGISTER when you need to refresh the registration. -Rockson -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tarun2 Gupta Sent: Friday, November 21, 2008 1:07 PM To: [email protected] Subject: [Sip-implementors] Query regarding 'To' tag in REGISTER request Hi All Consider the following scenario: REGISTER------------------------------>with Expires 3600 <-------------------------------------------- 200 ok with a 'To' tag and Expires 3600 Successful registration done. .. .. REGISTER-----------------------------> with Expires 0 and Contact * Is it ok for this de-REGISTER request not to have the 'To' tag as received in the 200 ok response? Whats the role of Tags in case of a REGISTER request? Thanks in advance. Tarun Gupta _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
