Mbone

Virtual Internet Backbone for Multicast IP.
IP-Multicast is the class-D addressing scheme in IP implemented by Steve Deering at Xerox PARC. It was adopted at the IETF March 1992 meeting and acquired the name MBONE after the July 1992 IETF meeting.
IP Multicast-based routing allows distributed applications to achieve real-time communication over IP wide area networks through a lightweight, highly threaded model of communication.
Each network-provider participant in the MBONE provides one or more IP multicast routers to connect with tunnels to other participants and to customers. The multicast routers are typically separate from a network’s production routers since most production routers don’t yet support IP multicast. Most sites use workstations running the mrouted program, but the experimental MOSPF software for Proteon routers is an alternative.
Ideally, the machines running mrouted should be dedicated to this task, for reasons of real-time performance and ease of installing kernel patches. Since most intermediate nodes have at least three tunnels, each carrying a separate (unicast) copy of each packet, it is also useful to have multiple network interfaces so it can be installed parallel to the unicast router for those sites with configurations like this:
+———-+ | Backbone | | Node | +———-+ | —————————————— External DMZ Ethernet | | +———-+ +———-+ | Router | | mrouted | +———-+ +———-+ | | —————————————— Internal DMZ Ethernet
This configuration allows the mrouted machine to connect with tunnels to other regional networks over the external DMZ and the physical backbone network, and connect with tunnels to the lower-level mrouted machines over the internal DMZ, thereby splitting the load of the replicated packets. The mrouted machine would not do any unicast forwarding.
Note that end-user sites may participate with as little as one workstation that runs the packet audio and video software and has a tunnel to a network-provider node.
RFC 1112 gives the details.
FAQ (http://eit.com/techinfo/mbone/mbone.html).
(1994-11-11)
multicast backbone