MOUNTAIN VIEW, Calif. – An event celebrating the 40th anniversary of Ethernet here drew pioneers with both war stories and poems from its past as well as practitioners and visionaries talking about the present and future of networking.
The event was timed to coincide with a 1973 memo Bob Metcalfe wrote at Xerox PARC that first described and named the technology. After Metcalfe sketched out his story in a keynote, the panel of pioneers below came on stage to fill in some of the details.
Metcalfe and others at the event were clear only two things remain of the original Ethernet--the name and the packet format.
As for spanning tree, no one mentioned prior art. I'll see if I can get Radia to chime in.
BTW, I was intrigued by the notion of "routing by name." Seems understandable enough that a name, assuming it's unique, is just as good an identifier as a 48-bit MAC address. My problem is, though, that unless names are carefully constructed, they will end up being just as un-hierarchical as MAC addresses are. Which makes actual "routing" a matter of every router having a list of all names. Hmmm.
Not to detract from the achievements of these smart people, but I don't think that this is the whole story. Necessarily.
For example, what Metcalfe did was brilliant, but little of it survives in today's Ethernet. The format of the basic "type" frame, yes. The carrier sense and collision detect protocol, with backoff, not really. That's not how the Ethenets work anymore. Ethernets of today are actually much simpler. Just fire off those frames, and if there's a traffic jam at a merge point, put them in a queue. (And all sorts of more or less implemented schemes for prioriting frames in a queue, which are not really standardized.)
If that original CSMA/CD protocol is used at all, it's only as a legacy protocol in a single host-switch interface. Does nothing to control traffic jams anymore.
The spanning tree protocol, I studied that from a book called "Flows in Networks," L.K Ford and D.R. Fulkerson, where the initial edition was dated 1962. It was applied to Ethernet, later on when switches were used to tie together Ethernet links, true enough. And it works very well indeed. And Radia's book is a good read, humorous, and even engrossing. But how about those other two very smart people, back in 1962?
January 2016 Cartoon Caption ContestBob's punishment for missing his deadline was to be tied to his chair tantalizingly close to a disconnected cable, with one hand superglued to his desk and another to his chin, while the pages from his wall calendar were slowly torn away.122 comments