Hi, That Cseq value is for that Cancel ,It is not copied from the INVITE.
Refer the section 20.16 from RFC 3261 for more details.. ... -- Balaji Murlitharan.C "truename" <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 11/24/2006 04:32 PM To [email protected] cc Subject [Sip-implementors] Question about Cseq in CANCEL request Hi all: There is a question confused me. In a session lanched by INVITE request, before replied a final status response, we can cancel this by a CANCEL request followed. Callid、FromTag、ToTag and Request-Url are enough to separate which INVITE request that the CANCEL request cancel. Why copy the number part of Cseq headfield? What is that surppose to? Here comes a example inferred by rfc3665: ----------------------------Callflow Start-------------------------------------------------------- Alice Proxy 1 | | | INVITE | |--------------->| | 100 | |<---------------| | 180 | |<---------------| | CANCEL | |--------------->| ----------------------------Callflow End------------------------------------------------------------ ----------------------------INVITE Message Start---------------------------------------------- INVITE sip:[EMAIL PROTECTED] SIP/2.0 Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 Route: <sip:ss1.atlanta.example.com;lr> From: Alice <sip:[EMAIL PROTECTED]>;tag=9fxced76sl To: Bob <sip:[EMAIL PROTECTED]> Call-ID: [EMAIL PROTECTED] CSeq: 1 INVITE Contact: <sip:[EMAIL PROTECTED]> Proxy-Authorization: Digest username="alice", realm="atlanta.example.com", nonce="ze7k1ee88df84f1cec431ae6cbe5a359", opaque="", uri="sip:[EMAIL PROTECTED]", response="b00b416324679d7e243f55708d44be7b" Content-Type: application/sdp Content-Length: 151 v=0 o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com s=- c=IN IP4 192.0.2.101 t=0 0 m=audio 49172 RTP/AVP 0 a=rtpmap:0 PCMU/8000 ----------------------------INVITE Message End---------------------------------------------------- ----------------------------CANCEL Message Start------------------------------------------------- CANCEL sip:[EMAIL PROTECTED] SIP/2.0 Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: Alice <sip:[EMAIL PROTECTED]>;tag=9fxced76sl To: Bob <sip:[EMAIL PROTECTED]> Route: <sip:ss1.atlanta.example.com;lr> Call-ID: [EMAIL PROTECTED] CSeq: 1 CANCEL Content-Length: 0 ----------------------------CANCEL Message End-------------------------------------------------- _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors *********************** Aricent-Private *********************** "DISCLAIMER: This message is proprietary to Aricent and is intended solely for the use of the individual to whom it is addressed. It may contain privileged or confidential information and should not be circulated or used for any purpose other than for what it is intended. If you have received this message in error, please notify the originator immediately. If you are not the intended recipient, you are notified that you are strictly prohibited from using, copying, altering, or disclosing the contents of this message. Aricent accepts no responsibility for loss or damage arising from the use of the information transmitted by this email including damage from virus." _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
