MBone

~ the eulogy ~

in 1994, when a rolling stones set went out over the mbone, i was ten and four years from my first modem. by the time i came online in 1998 the mbone was a research thing i had no way to reach, running on routers a dial-up account in ankara would never see. i know it the way an engineer knows a piece of plumbing that was sealed inside the walls before he showed up, from diagrams, not from having touched it.

the problem it solved was old and hard. the internet was built to send a packet from one machine to one other machine. if you wanted to send the same video to a thousand people, the obvious way was to send it a thousand separate times, which nothing could afford. ip multicast was the fix on paper, one stream that the network itself copies only where the paths split. the trouble was that almost no router in 1992 would actually route it. the mbone was the way around that, built by van jacobson and steve deering among others, a virtual network of tunnels that carried multicast between the few islands that understood it, riding on top of the plain internet in between.

for a few years in the mid-nineties the mbone was where the internet did its first live broadcasts. an ietf meeting in san diego went out over it in march 1992 to twenty listening sites, and by 1993 a band called severe tire damage had played the first live gig on the internet. a rolling stones show in 1994 pulled tens of thousands of people into grainy little windows. it dropped out constantly and felt like the future to everyone who managed to tune in.

~ the dossier ~

~ the long tail ~

a protocol dies slowly. through the late nineties the ordinary internet caught up: routers learned multicast natively, and backbones like internet2's abilene did in hardware what the mbone had faked with tunnels. raw bandwidth got cheap enough that sending a stream a few thousand times stopped being unthinkable. the overlay stopped being needed. bits of it lingered, a virtual conferencing system was still running on mbone tools as late as 2008, but as a live network with a name and a community it was gone by the early 2000s. there was no shutdown notice. the tunnels just stopped being lit.

~ what replaced it ~

the mbone lost as a network and won as a rehearsal. the tools van jacobson wrote for it, vat and vic among them, worked out how you packetize live audio and video and keep it in sync over a lossy link, and that work fed straight into rtp, the protocol underneath basically every video call and live stream since. multicast itself never really made it onto the open internet, killed by the same router politics that had forced the tunnels in the first place, but inside data centers and iptv networks it still runs quietly at scale. the mbone was wrong about how broadcasting would arrive and right about almost everything underneath it.

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