Multicast - routing over the Internet
Multicast traffic is not routable over the Internet.
If you attempt to route multicast traffic to the Internet it will simply be dropped. However, you can pass multicast through tunnels (such as a GRE tunnel) over the Internet to allow multicast to take place between two or more sites. However, this does not actually allow multicast over the Internet, it just allows multicast across your own private remote sites.
There are some experimental frameworks that have been used to attempt to deliver global IPv4 multicast functionality on the Internet. These include:
- GLOP multicast