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Ethernet: 30 years old and growing

Bangalore May 22. On May 22 1973, a young researcher at the Xerox Palo Alto Research Centre, in what was later to become America's Silicon Valley, circulated a memo to announce a new standard for linking computers together in a local area network (LAN). Robert M. ("Bob") Metcalfe groped for a name for the protocol, and remembered that scientists once thought (mistakenly) that a substance called "ether" pervaded all space. He decided it was time to give the word another lease of life, to describe a pervasive medium that would serve to push around packets of data. Thus was born the Ether Network, soon abbreviated to Ethernet: still the world's most widely used technology by which computers "talk" to each other.

Now 57, and a Massachusetts-based venture capitalist, Mr. Metcalfe is at his alma mater in Palo Alto, California, today to join in celebrations to mark his brain child's 30th birthday, even as network products leader Cisco announced that Ethernet would soon hit a mind-boggling top speed of 40 gigabits per second — that's 40 billion bits of data in a second. Currently Ethernet connections exchange data at best speeds of 10 gigabits per second — 3000 times faster than the first practical systems realised by Metcalfe and his associate David Boggs in 1974.

They devised a clever system by which two computers on a network listened to each other, then sent or received data only if there was no chance of a collision. It was called CSMA/CD: Carrier Sense Multiple Access/Collision Detection.

The ethernet card developed for this purpose is still one of the cheapest — around Rs. 200 — and most ubiquitous pieces of computer hardware, with over 100 million units sold worldwide. One of the reasons is that Mr. Metcalfe and his associates at 3Com, the networking company they founded in 1979, shunned the proprietary route and left the technology "open": In 1983, the Institution of Electronics and Electrical Engineers promulgated a standard based on their networking protocol called IEEE 802.3 that was in use till 1999, when it was overtaken by a new standard for gigabit Ethernet.

With the announcement of the 802.11 or "WiFi'' standard for wireless Internet access over short distances (it was adopted in India a few months ago) Ethernet is set for another change of "avatar" as a wireless connection system.

What does Ethernet's inventor think of all these breathtaking changes? Speaking to PC Magazine last week, Mr. Metcalfe suggested that since Ethernet speeds have increased 10 fold, every 10 years, we should be able to shift data at 10 terabits per second within the next decade (a terabit is a trillion bits or 10 raised to the power 12 bits).

One trend will still be around: networks will grow faster and bigger. Why? Because according to "Metcalfe's Law", "the value of a network grows as the square of its users".

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