Why Do You Need Multicasting?
“Necessity is the mother of all invention,” a saying derived from Plato’s Republic, holds very true in the world of technology. In the late 1980s, Dr. Steve Deering was working on a project that required him to send a message from one computer to a group of computers across a Layer 3 network. After studying several routing protocols, Dr. Deering concluded that the functionality of the routing protocols could be extended to support “Layer 3 multicasting.” This concept led to more research, and in 1991, Dr. Deering published his doctoral thesis, “Multicast Routing in a Datagram Network,” in which he defined the components required for IP multicasting, their functions, and their relationships with each other.
The most basic definition of IP multicasting is as follows:
Sending a message from a single source to select multiple destinations across a Layer 3 network in one data stream.
If you want to send a message from one source to one destination, you could send a unicast message.
If you want to send a message from one source to all the destinations on a local network, you could send a broadcast message. However, if you want to send a message from one source to selected multiple destinations spread across a routed network in one data stream, the most efficient method is IP multicasting.
Demand for multicast applications is increasing with the advent of such applications as audio and video web content; broadcasting TV programs, radio programs, and concerts over the Internet;
communicating stock quotes to brokers; transmitting a corporate message to employees; and transmitting data from a centralized warehouse to a chain of retail stores.
Success of one-to-many multicast applications has created a demand for the second generation of multicast applications that are referred to as “many-to-many” and “many-to-few,” in which there are many sources of multicast traffic. Examples of these types of applications include playing games on an intranet or the Internet and conducting interactive audio and video meetings.
Check attachment for IP multicast summary explanation & cmds
Edited by DarkFiber, 29 April 2009 - 06:11 PM.