Related specifications
RFC 3261, SIP: Session Initiation Protocol, available at http://www.ietf.org/
RFC 3264, An Offer/Answer Model with the Session Description Protocol (SDP), available at http://www.ietf.org/
Implementation notes
Support is provided for:
Hold. (Section 8.4, RFC 3264.)
Both unidirectional and bidirectional hold and resume.
Receiving of old-way hold. (Chapter B.5, RFC 2543.)
Support is not provided for multicast streams.