Contact Header is not *mandatory* for all the SIP messages. Only in few requests and responses the RFC mandates the Contact header.
Somesh * Please do not take print out of this e-mail unless its absolutely necessary * -----Original Message----- From: [email protected] on behalf of Avasarala Ranjit-A20990 Sent: Wed 2/4/2009 3:12 PM To: [email protected]; [email protected]; [email protected] Subject: Re: [Sip-implementors] [Sip] Is Contact Header mandatory in REFERmessage? Yes, Contact header is required for all SIP Messages. Here after, please post such questions and replies to sip-implementors mail list. Thanks Regards Ranjit ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, February 04, 2009 3:08 PM To: [email protected]; [email protected] Subject: Re: [Sip] Is Contact Header mandatory in REFER message? Thanks Sanjay. So, is the Contact Header mandatory for all SIP messages (Response and Requests)? Regards, Sunil ________________________________ From: Sanjay Sinha (sanjsinh) [mailto:[email protected]] Sent: Monday, February 02, 2009 2:18 PM To: Sunil Bhagat (WT01 - Telecom Equipment); [email protected] Subject: RE: [Sip] Is Contact Header mandatory in REFER message? Yes ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Monday, February 02, 2009 11:51 AM To: [email protected] Subject: [Sip] Is Contact Header mandatory in REFER message? Hi, Is it mandatory to have a Contact Header field in REFER message? RFC 3261 SIP: Session Initiation Protocol June 2002 8.1.1.8 Contact The Contact header field provides a SIP or SIPS URI that can be used to contact that specific instance of the UA for subsequent requests. The Contact header field MUST be present and contain exactly one SIP or SIPS URI in any request that can result in the establishment of a dialog. For the methods defined in this specification, that includes only the INVITE request. For these requests, the scope of the Contact is global. That is, the Contact header field value contains the URI at which the UA would like to receive requests, and this URI MUST be valid even if used in subsequent requests outside of any dialogs. If the Request-URI or top Route header field value contains a SIPS URI, the Contact header field MUST contain a SIPS URI as well. RFC 3515 The SIP Refer Method April 2003 2. The REFER Method REFER is a SIP method as defined by RFC 3261 [1]. The REFER method indicates that the recipient (identified by the Request-URI) should contact a third party using the contact information provided in the request. Unless stated otherwise, the protocol for emitting and responding to a REFER request are identical to those for a BYE request in [1]. The behavior of SIP entities not implementing the REFER (or any other unknown) method is explicitly defined in [1]. A REFER request implicitly establishes a subscription to the refer event. Event subscriptions are defined in [2]. A REFER request MAY be placed outside the scope of a dialog created with an INVITE. REFER creates a dialog, and MAY be Record-Routed, hence MUST contain a single Contact header field value. REFERs occurring inside an existing dialog MUST follow the Route/Record- Route logic of that dialog. Regards, Sunil _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors EMAIL DISCLAIMER : This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. Any unauthorised distribution or copying is strictly prohibited. If you receive this transmission in error, please notify the sender by reply email and then destroy the message. Opinions, conclusions and other information in this message that do not relate to official business of Mascon shall be understood to be neither given nor endorsed by Mascon. Any information contained in this email, when addressed to Mascon clients is subject to the terms and conditions in governing client contract. Whilst Mascon takes steps to prevent the transmission of viruses via e-mail, we can not guarantee that any email or attachment is free from computer viruses and you are strongly advised to undertake your own anti-virus precautions. Mascon grants no warranties regarding performance, use or quality of any e-mail or attachment and undertakes no liability for loss or damage, howsoever caused. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
