On Tue, 2008-12-02 at 16:39 +0530, Anita Tailor wrote: > RFC 3261 Section 20.19 > > " The value of this field is an integral number of seconds (in > decimal) > between 0 and (2**32)-1, measured from the receipt of the request"
> Does this mean 0 is a valid value of Expires header ? I am confused > because of "between" word here as meaning might different if "from 0 > to (2**32)-1" have used. "Expires: 0" is definitely valid, as it is used in SUBSCRIBEs that do "one-shot retrieval" of event packages. See RFC 3265. > Does Expires value in INVITE is modified by intermittent SIP entities > before it reaches to its destination? Yes, it can be modified by SIP proxies. (Officially, the proxy is forwarding the message to the URI "sip:[EMAIL PROTECTED]". Since the "Expires" header cannot be repeated, the new value replaces the old value.) > If yes, then what should be UAS behavior when it receives INVITE with > value 0 in Expires header ? Should UAS respond with 487 ? The concept is that the INVITE expires immediately. What might this mean? Clearly, the UA cannot "ring" for any length of time. This suggests that the INVITE should be given an immediate 487 response. However, it seems that there should be an exception: If the UAS is set to answer immediately (that is, to respond 200 without waiting for human intervention), as happens in some applications, it could instead immediately respond with 200. Dale _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
