What Is IP Multicast?

• Microsoft NetShow version 2.0

SUMMARY

The section below discusses what IP multicast is.

MORE INFORMATION

IP multicast is not a true network broadcast transmission. It is similar to a radio station that transmits a signal everyone listens to or "tunes" into. You can compare this "broadcast" to a cable broadcast that is like a normal TCP connection. Multicasting is session-less networking (like the terrestrial TV broadcast) vs. other Internet connections, such as the HTTP connection to a web server.

The advantage of IP multicast is it uses a constant amount of bandwidth. The disadvantage is a multicast route (or pathway) between the server and the client must exist. In this case, that means all of the networking equipment in between and the connections must both support and be enabled for IP multicasting routing.

Currently IP multicast is best suited for intranets and will not work in most cases on the Internet. You can expect to see IP multicast gain momentum on the Internet as it evolves. As new infrastructure is added, you will see this becoming more and more prevalent.

NOTE: You can "tunnel" IP multicast broadcasts using UNIX computers. Therefore, when you are broadcasting your signal on the Internet, you do not need to setup or configure a multicast channel or program. The least complex configuration would be to configure a Unicast Server publishing point and use the real time encoder as the source of this server alias.