Multicasting in Computer Network

Multicast is a method of group communication where the sender sends data to multiple receivers or nodes present in the network simultaneously. Multicasting is a type of one-to-many and many-to-many communication as it allows sender or senders to send data packets to multiple receivers at once across LANs or WANs. This process helps in minimizing the data frame of the network because at once the data can be received by multiple nodes. 

Multicasting is considered as the special case of broadcasting as.it works in similar to Broadcasting, but in Multicasting, the information is sent to the targeted or specific members of the network. This task can be accomplished by transmitting individual copies to each user or node present in the network, but sending individual copies to each user is inefficient and might increase the network latency. To overcome these shortcomings, multicasting allows a single transmission that can be split up among the multiple users, consequently, this reduces the bandwidth of the signal.
Applications : Multicasting is used in many areas like:

1. Internet protocol (IP)
2. Streaming Media
3. It also supports video conferencing applications and webcasts.

– Multicasting use classful addressing of IP address of class – D which ranges from 224.0.0.0 to 239.255.255.255

IP Multicast : Multicasting that takes place over the Internet is known as IP Multicasting. These multicast follow the internet protocol(IP) to transmit data. IP multicasting uses a mechanism known as ‘Multicast trees’ to transmit to information among the users of the network. Multicast trees; allows a single transmission to branch out to the desired receivers. The branches are created at the Internet routers, the branches are created such that the length of the transmission will be minimum. 

IP multicasts also use two other essential protocols to function; Internet Group Management Protocol (IGMP), Protocol Independent Multicast (PIM). IGMP allows the recipients to access the data or information i.e if any host wants to receive the message that is going to be multicasted, they must join the group using this protocol. The network routers use PIM to create multicast trees. To sum up, Multicasting is an efficient way of communication; it reduces the bandwidth usage and is used when a message is to be sent to a large number of selected individuals.