Multicast is also referred to as point-to- multipoint connection( P2MP). With multicasting, information is transmitted along the optimal transmission path with as little duplication as possible. The advantage of multicasting is that messages can be transmitted simultaneously via one address to several subscribers or closed user groups(GBG) without the required bandwidth increasing with the number of receiving devices.
Multicast is suitable for various services such as telephone conferencing and web conferencing, telelearning, software distribution, for Internet television and Internet radio, and payment services. In addition to multicast, there is unicast, anycast, broadcast, and geocast, and in IP networks, IP multicast. Multicast protocols include: Distance Vector Multicast Routing Protocol( DVMRP), Multicast Open Shortest Path First( MOSPF) and the Protocol Independent Multicast( PIM).