Mbone (short for "multicast backbone") was an experimental backbone for IP multicast traffic across the Internet developed in the early 1990s. It required specialized hardware and software. Since most Internet routers have IP multicast disabled due to concerns of bandwidth tracking and billing, the Mbone evolved to connect multicast-capable networks over the existing Internet infrastructure. The commercialization of multicast routers is difficult because there are no efficient access control capabilities to the multicast trees (multicast routers and their protocols), and because Internet service providers have difficulty computing charges for multicast traffic.
A November 1994 Rolling Stones concert at the Cotton Bowl in Dallas with 50,000 fans was the "first major cyberspace multicast concert." Mick Jagger opened the concert by saying, "I wanna say a special welcome to everyone that's, uh, climbed into the Internet tonight and, uh, has got into the M-bone. And I hope it doesn't all collapse."
By 1995 there were M-bone links in Russia, as well as at the McMurdo Sound research station in Antarctica.
Mbone is currently of practical use for shared communication such as videoconferences or shared collaborative workspaces. It is not generally connected to Internet service providers, but often to universities and research institutions. Some other projects and network testbeds, such as Internet2's Abilene Network, have made Mbone obsolete.
A recent application with support over Mbone was Virtual Room Videoconferencing System (VRVS)
Read more here
