The encyclopedia · Software & IT · Strategic decision · 1973–1985
Ethernet won the LAN standard by being simple and by Xerox opening it to DEC and Intel.
A simple coaxial bus with collision detection ran on cheap wire, and Xerox opened it, so Ethernet beat Token Ring and Token Bus.
Xerox · DEC · Intel · 3Com
the move
In 1973 Bob Metcalfe, working at Xerox PARC, wrote a memo proposing a way to connect the new Alto personal computers and the first laser printer over a shared coaxial cable. Dave Boggs turned it into a working network by November 1973.
The design was deliberately simple: every machine listened to the wire, sent only when it was quiet, and if two collided they backed off and retried. That carrier-sense with collision-detection rule made Ethernet cheap, fast enough to drive a laser printer, and easy to extend with more machines.
The decisive move was not the wiring but the openness. Metcalfe persuaded Xerox to join DEC and Intel to publish the DIX specification and make Ethernet an open standard. So instead of a Xerox-locked network, it became IEEE 802.3, and 3Com, Intel and a long list of vendors all built for it.
why it works
- A single shared coaxial bus with a simple collision rule was cheap and worked on ordinary wire, so it was affordable to deploy.
- It scaled as machines were added without reconfiguring the network, so growth did not require re-engineering.
- Xerox releasing the patents and publishing the specification let DEC, Intel and others build and improve it.
- Becoming IEEE 802.3 made it the default choice against IBM's token-passing Token Ring and GM's Token Bus.
what transfers
A standard wins when it is simple and cheap to implement and the patent holder opens it - complexity and exclusivity will lose to 'good enough and universally adoptable'.
what came after
Ethernet became the dominant local-area networking standard, evolving from 10Mbps thick coax to 10BASE-T twisted pair, Fast Ethernet, Gigabit and beyond. It supplanted Token Ring and Token Bus, and its frame format is the underlying plumbing of the modern internet.
references
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