Below are my thoughts on the TCP transport type. Regards, Indresh K Singh ------------------------------------------------------------- Sr. Software Engineer SIP Media Control and Signaling Nokia Siemens Networks Boca Raton, FL-33487 Ph: 561-923-5085 (o), 561-923-2048 (o) -------------------------------------------------------------
>>-----Original Message----- >>From: [EMAIL PROTECTED] >>[mailto:[EMAIL PROTECTED] On Behalf >>Of ext Sweeney, Andrew (Andrew) >>Sent: Thursday, May 10, 2007 9:38 AM >>To: [email protected] >>Subject: [Sip-implementors] Is transport=tcp mandatory if a >>TCP connectionis being established? >> >>I am trying to determine if transport=tcp must be added to a request >>when the user is going to run over TCP. >> For SIP URI it should add transport=tcp in the relevant headers like R-URI/Via/Contact. UAC may choose to receive responses on UDP even though it sent the initial request on TCP, then the via header would indicate so in the via header transport parameter. UAC may also choose to receive subsequent messages on UDP, even though it sent the initial request on TCP or other thansport, in that case it would indicate so in the contact header transport parameter. Only for SIPS URI the default transport is TCP. So if R-URI or other headers are used with SIPS URI scheme then it is not explicitly needed to specify transport = TCP uri transport parameter >> >> >>In other words can a TCP request be made without >>transport=tcp being set >>in the request URI. >> >> It can be only done if the URI scheme of R-URI is SIPS. >> >>Another question in this area. >> >> >> >>What is the proper way to handle this scenario. >> >> >> >>A remote device initiates and establishes a connection over TCP but >>doesn't include transport=tcp in the uri or the contact. >> >> >>The local device wants to do a transfer with re-invite. Can he do this >>over udp or must he use tcp since the original dialog is on TCP? >> Not Clear how the remote devices established the connection over TCP. It can only do so with SIPS URI. ' If for establishing the call over TCP both the UAC and UAS used SIPS URI and did not explicitly specify transport = TCP. Then the re-INVITE transport type has to be choosen based on the transport capability indicated by UAS in the response messages. In the absence of explicit transport type specification in the contact header of response, the default transport type is selected based on the URI type being SIP or SIPS. This is what would dictate the transport for the re-INVITE for any purpose. >> >>Thanks >> >> >> >>_______________________________________________ >>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
