Metcalfe’s Law after 40 Years of Ethernet

I enjoy reading about industrial automation. One of the magazines I read regularly is Computer magazine (the digital edition, of course). Since PROFINET runs on Ethernet, an article in the December issue caught my eye: “Metcalfe’s Law after 40 Years of Ethernet” written by Bob Metcalfe himself.

He set out to prove that his law was still valid. He states Metcalfe’s Law as “the value of a network grows as the square of the number of its users.” He cites examples from the early days of Ethernet, then uses Facebook as an example to verify it today.

Some sidelights that I found interesting:

“Ethernet was born on May 22, 1973, in a memo I circulated and the Xerox Palo Alto Research Center (PARC) showing how a local area network (LAN) might work.”


Perhaps that’s enough to whet your appetite to read the whole article… although you have to be a subscriber or pay per article. For free you can read more about Metcalfe’s Law at Wikipedia.  I recommend subscribing to Computer magazine though.

–Carl Henning