Hi Sudhir, "Supported" and "Require" are known as headers rather than methods. These two headers have the following significance as per RFC 3261 : 20.32 Require The Require header field is used by UACs to tell UASs about options that the UAC expects the UAS to support in order to process the request. 20.37 Supported The Supported header field enumerates all the extensions supported by the UAC or UAS.
If INVITE contains just "Supported" header, the UAS "MAY" send the non-100 responses reliably as stated in RFC 3262 If INVITE contains "Require" header, the UAS "MUST" send the non-100 responses reliably. If it does not support this extension, it should respond to the INVITE with "420 Bad Extension" response. Its valid for a UAC to send INVITE with just "Require: 100 rel" header as well. Best Regards, Rekha (ESN : 6-877-5834) (PSTN : 81168) ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Sudhir Kumar Reddy Sent: Tuesday, February 19, 2008 4:00 PM To: sip@ietf.org Subject: [Sip] is supported and require is Mandatory in INVITE request Hi All, Is supported and require methods are required for INVITE request (RFC 3262) or any of method(either Supported or require) will suffice for INVITE for Provisional ACK. Because I see in one of INVITE(from server) sending only require: 100Rel, but there is no Supported Header. Should we treat as complete or incomplete request? Any response is highly appreciated. Thanks in Advance Sudhir
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