Multicast routing


Multicast Routing is one of the routing protocols in TCP/IP communication.
In computer networking, there are several multicast group communication protocols where data transmission is addressed to a group of destination computers simultaneously.

Overview

Multicast routing is a method of transmitting to all subscribers registered in a group by one transmission unlike unicast routing which transmits 1: 1 necessary data.
To implement the multicast routing, IGMP protocol and multicast routing protocol for registration subscriber grouping and control traffic are required for multicast transmission. Regarding IP multicast, it is a technique for one-to-many communication over an IP network. IP multicast covers some part of common multicast routing protocol. IP multicast also describe IP multicast software. The multicast routing is specific and broad range of protocols for layer-3 routing protocol for multicast feature and it is defined on overview of the Internet Multicast Routing Architecture RFC5110.

Routing mechanism

A multicast routing protocol is a mechanism for constructing a loop-free shortest path from a source host that sends data to the multiple destinations that receives the data. IPV4 uses Class D address
IPv6 multicast provides the previous feature of IPV4 and a new IPv6 feature, allowing a host to send a single data stream to a subset of all hosts concurrently.
There are four types of Well-Known IPv6 Multicast address range : ff02::1: All IPv6 devices,•ff02::2: All IPv6 routers,•ff02::5: All OSPFv3 routers,•ff02::a: All EIGRP routers.

The Multicast tree classification

There are two types of Multicast trees which are the Source based tree and Group Shared tree.

Group Shared tree

It is Core-Based Tree, selecting one router in the network as the root and transmitting information through the root router. Maximum delay in the tree is longer than SBT, The core router manages all the information, and the remaining routers manage the direction of the core and the multicast information requested by the current neighboring router. it has a Good Scalability. Supported protocols include CBT, PIM-SM, etc.