mbone

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 {thread}ed 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)