Hi, RFC3261 says that a UAC should send inmediately a BYE after a 2XX response if the offer in the 2xx response is not acceptable (when the INVITE has no body). So this will generate an answered call of duration 0 (probably).

But if the CDRTool rate has "connect" fixed amount then this invalid call will have cost. I think this shouldn't have cost since it's a SIP protocol issue (accepting a call and sending a BYE inmediately) but not an human decision.

Opinions?

13.2.2.4 2xx Responses