It is not neccessary that the registrar returns the date and most registrars don't do it.
The idea was that a SIP user agent can skip NTP or other methods to get the date, including the provisioning of a NTP server. Also, as far as I remember the first SIP versions allowed to return an absolute expiry date, and it was useful to have the registrars opinion about the current time. However, if you write a SIP user agent, you cannot rely on it and you must implement your own mechanism to get the time. At the time when the standard was made most registrars did not do it and they would be not compliant, so the common denominator was to suggest to do it - but don't require it. CS -----Ursprüngliche Nachricht----- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Iñaki Baz Castillo Gesendet: Montag, 3. März 2008 03:46 An: [email protected] Betreff: [Sip-implementors] Is "Date" header mandatory in a REGISTER's 200OK? Hi, I'm sure that "Date "header is not mandatory at all in the 200 OK to a REGISTER. In fact I don0t know a registrar adding it. But RFC 3261 says: ------------------------------------------------------------------ 10.3 Processing REGISTER Requests 8. The registrar returns a 200 (OK) response. The response MUST contain Contact header field values enumerating all current bindings. Each Contact value MUST feature an "expires" parameter indicating its expiration interval chosen by the registrar. The response SHOULD include a Date header field. ------------------------------------------------------------------ But it also says: ------------------------------------------------------------------ 10.2.5 Setting the Internal Clock If the response for a REGISTER request contains a Date header field, the client MAY use this header field to learn the current time in order to set any internal clocks. ------------------------------------------------------------------ So? is that "Date" header a SHOULD or a MAY? -- Iñaki Baz Castillo [EMAIL PROTECTED] _______________________________________________ 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
