Except as specified in the following sections, the rules for
message processing are as specified in [RFC3261] and [RFC3265].
The following events are specified in this section:
Receiving a Failure Response
to SUBSCRIBE (section 126.96.36.199)
Receiving a Success Response
to SUBSCRIBE (section 188.8.131.52)
BENOTIFY (section 184.108.40.206)