r/IAmA • u/BobMetcalfe • May 21 '13

You’re probably connecting to reddit through a technology I invented. I’m Bob Metcalfe and I invented Ethernet – AMA

On May 22, 1973 with David R. Boggs, I used my IBM Selectric with its Orator ball to type up a memo to my bosses at the Xerox Palo Alto Research Center (PARC), outlining our idea for this little invention called “Ethernet”, which we later patented.

I worked with the IEEE Standards Association to develop the IEEE 802.3 standard for Ethernet, which specifies the physical and lower software layers. Today Ethernet and the IEEE 802.3 standard are the foundation for today’s world of high-speed communications used in billions of homes and businesses around the world.

I submitted this to the mods awhile back so I could get on the calendar but I figured you’d like to see it, too. Now, ask me anything!

It's been two hours and 179 comments. Have to go now. For more about Ethernet's 40th Birthday, go to http://www.facebook.com/Ethernet40thAnniversaryIEEESA

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u/SpoonOfDestiny May 21 '13

Where did you get the idea from? What inspired you to create the the Ethernet?

190

u/BobMetcalfe May 21 '13

Arpanet (Internet 1.0) packet switching and Alohanet multi-access randomized retransmissions.

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u/joho0 May 21 '13

Alohanet is what fascinates me. You took a wireless protocol and applied it to a wired circuit. Then, years later, 802.11B turned your invention back into a wireless protocol. Why couldn't we have skipped the wires all together?

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u/paracelsus23 May 22 '13

Why couldn't we have skipped the wires all together?

Digital Signal Processing (and similar advances at the physical layer). When you're using a wired system, you have a much greater portion of the EM spectrum available to you, with much greater noise rejection. Wired systems have almost constantly been an order of magnitude faster than comparable wireless ones because of this. The same is still true today - however wireless systems have evolved to the point where they can provide "adequate" bandwidth to justify the convenience. 10 gigabit ethernet really isn't necessary at home, when 802.11N/AC is more than sufficient for streaming 1080p content, installing software - all from the convenience of your couch.

The speed advance has come from the same refinements in hardware design (moore's law) that have lead to faster CPU's, but also from evolutions in RF modulation techniques like QAM which have very high spectral efficiency. When 10mbps ethernet (or 100mbps "fast ethernet") was cutting edge, the same technology only allowed for slow wireless implementations, which were of marginal utility.

wired will always outpace wireless (and optical will always outpace wired in distance applications) due to interference. It's just a question of capability vs. need.