This Recommendation | International Standard describes the Mobile Multicast Communications (MMC)@ which can be used to support a variety of multimedia multicasting services in IP-based wireless mobile networks as well as wired fixed networks. MMC targets real-time@ one-to-many multicast services and applications over mobile communications networks. This implies that MMC focuses on multicast services rather than broadcast services@ and that only authenticated users could be allowed in the multicast session. MMC also considers the one-to-many multicast session wherein a single multicast sender is allowed in the session rather than many-to-many multicast services. In addition@ MMC is targeted in the real-time multicast session rather than the reliable multicast session; the timely delivery of multicast data is considered a key factor. This Recommendation | International Standard specifies the MMC framework as part of the MMC standard describing the framework and functional architecture of MMC. Based on this framework@ the two protocols for MMC will be developed in two parts of the MMC project: protocol over native IP multicast networks and protocol over overlay multicast networks.