[SIPForum-techwg] Could to-tag in 200 OK response be different with the to-tag in 180 ringing?

[mike xu]

Hi All,

Do you know that in RFC3261, could the to-tag in 200 OK be different
with the one in 180 ringing?
Below is the case which I met, in step F1 (180 ringing), callee
generated one to-tag (46bf8) while in step F2 (200 OK) the sip server
generates a new to-tag which is "as5123fc8f", and my sip endpoint
didn't match this 200 OK response, the sip server will resend 200 OK
and I obveriously couldn't hear the voice mail info.

   Caller        SIP_SERVER       Callee
     |                |              |
     |       INVITE    |             |
     |------------->|  INVITE      |
     |    (100 Trying)  |----------->|
     |<-------------|              |
     |                |180 Ringing F1 |
     |   180 Ringing   |<-----------|
     |<-------------|              |
     |                |   CANCEL     |
     |                |----------->|
     |                |   200 OK     |
     |                |<-----------|
     |                |487 Req Cancel |
     |                |<------------|
     |                |     ACK       |
     |                |------------>|
     |200 OK(SIP/SDP) F2|               |
     |<-------------|               |
     |    ACK         |               |
     |------------->|               |
     | voicemail RTP   |               |
     |<===============||               |

Does any body know that the new to-tag in F2's 200 OK response is
valid or invalid? Does it comply to RFC3261?

Thanks,
Mike