Ethernet keeps going and going . . .

Bob Metcalfe, the guy who’s credited with inventing Ethernet, recalls its 1973-74 genesis at Xerox PARC in a 16-minute video presentation on Youtube. Robert MetcalfeHe credits ALOHAnet’s pioneering packet radio concepts and speaks about the original idea of an RG-8 coaxial cable (10base5 or “thicknet”) backbone with a vampire-tapped MAU (Media Access Unit) to feed each node. I haven’t seen this type of construction in many years. It achieved his goal of reducing wire closet clutter.

While using today’s twisted-pair 100baseT cables and switches in physical star topologies, it’s easy to forget that logically they’re the same as the original Ethernet. They all use the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Media Access Control (MAC) method, so they can all interconnect on the same local area network.

Ethernet’s Free-for-All Model Prevails

Decades ago, I guessed wrong. I thought that the deterministic model that created the Token-Ring MAC access mode (championed by IBM and Proteon) would win. Token-ring outperformed Ethernet in heavily-loaded networks, but its system complexity, difficult construction, and higher cost were its undoing. When cheap and easy 10baseT cables, hubs, and switches arrived, they delivered the coup de grâce to Token-ring.

ListenMr. Metcalfe can be heard in a recent 22-minute audio clip in which he discusses his subsequent experience in business (he founded 3Com) and his simple advice to salespeople on how to close a sale.

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© Russ Bellew · Fort Lauderdale, Florida, USA · phone 954 873-4695


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