Voice Over IP

IGMP and MBONE

Multicasting (sending from one party to two or more parties) is of keen interest to internet telephony users and designers because it paves the road for conference calls, a fundamental part of doing business in many companies. The Internet has supported multicasting for a number of years with the Internet Group Management Protocol (IGMP).

This protocol defines the procedures for a user node (a host) to join a multicast group. Once the host has joined the group, it can receive any multicasting traffic sent within this group. For example, the multicast session may be a quarterly conference of a special interest group, or it may be a Rolling Stones concert.

One of the attractive features of IGMP is that it does not require a host ...