Introduction to IP Multicasting

IP  Multicasting is a technique of distributing the data across multiple servers over the WAN.  It is simply the delivery of the same data packets to the multiple destinations.  It allows the multiple recipients to receive the same data packets from a single source. Multicasting allows the distributed applications to work over the WAN with great performance.  It is an excellent alternative for the unicast and broadcast transmissions.

In Multicasting, the information is sent to only the destined recipients.   It is like the TV or radio transmission system in which only those terminals receive the information who have tuned themselves to receive it. It is the bandwidth-conserving technology that reduces the traffic load over the network.  The ideal applications that uses the multicast technology includes video conferencing, stock quotes, distance learning, weather updates, video streaming, news and other distributed software applications in the LAN/WAN network.  IP multicasting mechanisms depends upon the two protocols i.e. group management protocol and the routing protocols.

Group Management protocols establish the multicast groups and the routing protocols routes the traffic to the destination. Multicast routing protocols makes the distribution tree for the data forwarding in the network. It is an ideal solution for the distribution applications in the TCP/IP based LAN/WAN networks. 

Though it has been successful in many businesses but it is not extensively deployed and used by the average users.  Special addressing scheme is assigned while implementing the IP multicasting.  These addresses are assigned from the Class D i.e. 224.0.0.0 to 239.255.255.255.  The typical multicast applications include the following.

• Video conferencing
• Audio conferencing
• Stock Quotes
• Distributed LAN/WAN Software Applications
• Weather Updates
• Data Conferencing
• Network-based games
• Online Training
• Database replication

Multicasting applications minimize the demand of the network bandwidth while sending the information from one source to multiple destinations via same stream.

Multicasting can be implementing in the following situations.

• For better bandwidth utilization.
• Less Router/Hosts Processing.
• When sending the same data to the multiple receivers is required.
• When the recipient address is unknown.
• When a one-to-many communication systems model is required.

It has many advantages over the unicast and broadcast communication system such as the following.

• Enhanced performance.
• Optimized performance.
• One-to-many communication system.