[Sip-implementors] [Q] Does CANCEL message include To tag from provisional response?

[이승환]

Hi.

I'm developing sip product based on SIP-bis9.

My Question is below...

1. UA-1 sent INVITE message to UA-2(don't have To tag).
2. UA-2 respond 180 Ringing(include To tag).

Above situation, if UA-1 send CANCEL, does the CANCEL message include To tag from 180 Ringing Response Message?






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