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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.

It is best if the workstations can be dedicated to the multicast routing function to avoid interference from other activities and so there will be no qualms about installing kernel patches or new code releases on short notice. Since most MBONE nodes other than endpoints will have at least three tunnels, and each tunnel carries a separate (unicast) copy of each packet, it is also useful, though not required, to have multiple network interfaces on the workstation 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.



(Multicast backBONE) A group of servers throughout the Internet that support the IP multicast protocol (one-to-many) and allow for live audio and video transmission. When it is necessary to leave the Mbone and traverse a part of the Internet that does not support multicast packets, the packets are tunneled into normal packets. Mbone routers (mrouters) encapsulate the multicast packets into unicast packets and unencapsulate them on the receiving side.
References in periodicals archive ?
Judy Estrin, Precept CEO, said, "The MBone, originally created as a collaborative research tool, has broadened into a mainstream channel carrying everything from live space shuttle transmissions to worldwide technical conference broadcasts to rock concerts.
As a pioneer in the commercialization of MBone technology, we want to help ensure that the broadest possible body of academic and research personnel have low-cost access to membership in the MBone community.
With Precept's IP/TV Viewer for the MBone, users can watch programs being transmitted from a VIC/VAT server or an IP/TV server anywhere on the Internet, choosing from a list of programs scheduled to run on the MBone.
Available immediately to members of the academic and research communities, the IP/TV Viewer for the MBone (IP/TV version 1.
By making multicast programming available in the controlled Mbone environment, Telecom Finland is paving the way for others and helping Xing ensure that StreamWorks will support multicast as enabled networks emerge.
Telecom Finland deploys high-speed ATM (asynchronous transfer mode) technology for the Internet backbone which supports Mbone and multicast technology.
The Mbone is a virtual network on top of the Internet.
Originally used primarily for research purposes, the MBONE today regularly carries multicasts of IETF meetings, space shuttle flights, academic conferences -- even rock concerts, such as last year's highly publicized live Rolling Stones concert.
The Slidecast feature will operate with both 16- and 32-bit IP/TV clients, as well as on UNIX- and Apple-based MBONE tools.