Multicast

Multicast is a the delivery of information to multiple destinations simultaneously. Typically used to refer to IP Multicasting, which is a protocol for efficiently sending to multiple receivers at the same time on TCP-IP networks, by use of a multicast address. It's also commonly associated with audio/video protocols such as RTP.

By comparison with multicast, conventional point-to-single-point delivery is called unicast[?].

There are two basic kinds of multicast delivery:

• dense multicast[?]
• sparse multicast[?]

Modern multicast algorithms are often capable of combining and managing the two.

Multicast is not in general use in the commercial Internet, due to interoperability problems and the lack of a compelling business model for multicast.

However, some communities within the public Internet make regular use of multicast (see the MBONE[?] for an example), and multicast is used for special applications within private IP networks.

IP multicast protocols

• Protocol independent multicast[?] (PIM)
• Distance vector multicast routing protocol[?] (DVRMP)
• Multicast OSPF[?] (MOSPF)
• Multicast BGP[?] (MBGP)
• Internet group management protocol (IGMP)

See also:

• Spanning tree
• Flooding algorithm
• Anycast[?]

External links

• IP Multicast Applications: Challenges and Solutions (RFC 3170) (http://www.rfc-editor.org/rfc/rfc3170.txt)