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Happy Birthday Ethernet!

Happy Birthday Ethernet!

Ethernet, with all the talk about gigabit this and even terabit that, has never looked younger. But we old timers know that this venerable LAN technology has been kicking around for a while - a long while. In fact, Ethernet turned 25 late last month. That's right. On May 22, 1973, Bob Metcalfe sat down in front of an IBM electric typewriter and cranked out a 13-page description of Ethernet. Metcalfe believes this document represents the very invention of the technology. In 1979 he founded 3Com to commercialise his invention. Along the way, he had some significant help in refining the technology, including assistance from some of the industry heavyweights queried for the story. IDG journalist Paul Desmond recently caught up with Metcalfe, now IDC's vice president of technology, to get his thoughts on EthernetDesmond: Where do you see Ethernet going from here? Is there a limit to how far the technology can go speed-wise?

Metcalfe: We're at Gigabit Ethernet now but the wheels are clearly in motion to follow that - it's already going on in places. We'll eventually get to Terabit Ethernet - that's an easy prediction.

Ethernet used to mean CSMA/CD LAN. Now it means something different. Ethernet is sort of a name for a cadre of companies that over almost 20 years has learned how to build a series of businesses based on standards.

That's what Ethernet means - it means that cadre of companies. It's Ethernet in a much stronger, new sense and it's one of the reasons why Gigabit Ethernet has been kicking ATM's butt recently - because the ATM people don't know how to operate this way.

You mean cooperating and launching standards?

Yes, the ATM people just don't know how to do it. We saw it with ISDN, which was a poor implementation - weakly standardised, slowly deployed, if at all, and then overcharged for, without any competition. ATM comes out of that same group which doesn't know how to make standards, doesn't know how to migrate and doesn't know how to compete, which is probably its greatest weakness.

That would be a systemic explanation for why Gigabit Ethernet has been kicking ATM's butt.

What do you see as the key challenges to Ethernet going forward?

Getting into the home. In order for Ethernet to become residential in any big way, just as we saw with business, a LAN has to develop first because most of the traffic is LAN traffic and a small fraction leaks out into the WAN. So a big challenge is for Ethernet to evolve on the low end - to become cheap and easy to use.

Will Ethernet have a 50th birthday, or will it be just a memory by the year 2023?

I predicted that 2003 would be the last year in which a new Ethernet product would be announced. But I made that prediction based on the 10bps limit. That was before I saw, as others saw, that you could speed it up. That's been going on steadily. When you go switched and eliminate collisions entirely, the sky's the limit.

So you're saying it will have a 50th birthday?

Absolutely. I've changed my mind. And I hope to attend the party. Wouldn't that be nice?

What has most surprised you about the evolution of Ethernet?

Other than the fact that it passed 100 million connections a long time ago? Other than the fact that 3Com is now a $US7 billion company? Those are two big surprises. I'm surprised about how ugly the process is of standardising and competing around a standard. It's intrinsically ugly, and it works beautifully. But you have to have a stomach for street fighting. That was kind of a surprise. Innovation is not some artist's conception of innovation. It's really rough and tumble and that's necessary for it to work, and it does work brilliantly. Evidence - Gigabit Ethernet prevailing over ATM.

At right are the thoughts of Vinod Bhardwaj, co-founder of Kalpana, the company credited with producing the first Ethernet switch; Scott Bradner, a consultant with Harvard University's University Information Systems; Vinton Cerf, senior vice president of Internet architecture and engineering at MCI Communications; Eric Cooper, CEO of Fore Systems; and Bernard Daines, a consultant to 3Com on its first commercial Ethernet products, co-founder of Fast Ethernet switch maker Grand Junction Networks, and current chairman, president and CEO of Gigabit Ethernet switch vendor Packet Engines. Paul Desmond reportsDesmond: Where do you see Ethernet going from here? Is there a limit to how far the technology can go speed-wise?

Cerf: The basic design can work beyond gigabits, but the physical size of the network has to shrink to make it so. Beyond tens of gigabits, it is hard to tell whether it will still be useful, except as a very local interconnect method. Of course switched Ethernet may well work fine at higher speeds, since only one device occupies each "spoke" and the switching does what the shared Ethernet did at lower speeds.

Bhardwaj: There is no limit on how far the technology can go. For fibre, we should see 10Gbps Ethernet soon. For copper, although the current limit seems to be 1Gbps on four pairs, with improvements in cable and by sheer ingenuity of future creative engineers, it will be possible to exceed the current 250Mbps per pair limit. Even higher speeds could be obtained by using more than four pairs in a cable. You could have a flat cable with 24 pairs running at 10Gbps.

Cooper: It's already a stretch to call Ethernet a "technology". Now it's mainly just a logical specification of address and frame formats. The early technology of shared media access, collision detection and avoidance and so on has been made vestigial, if not quite completely irrelevant, with the advent of switch-based, dedicated-access networks.

What do you see as the key challenges facing the technology?

Bhardwaj: For the copper version, it is the limitations of the analog circuitry. A special semiconductor process might be needed just for analog, which could provide higher speed transistors at higher voltages and with better substrate noise isolation. I doubt if the current gigabit standard would work reliably on the installed base of CAT 5 cable and connectors with current state-of-the-art analog technology.

Cooper: The Ethernet-compatible frame size of 1500 bytes is a brick-wall impediment to high performance. This is already evident in the Gigabit Ethernet arena, where vendors must resort to proprietary, not Ethernet, larger frames to achieve respectable performance. Ironically, ATM surmounted this challenge years ago by logically separating the notion of small fixed-size cells from larger variable- size frames and using inexpensive silicon to do the conversion.

Cerf: Dealing with higher speeds, possibly rearchitecting to work in optical mode, with optical switches and transverse filters.

Daines: That we don't trivialise it. In some ways the reason for Ethernet being so successful over the last few years is there have been challenges. 100VG-AnyLAN was challenging, so people who were doing 100Mbps Ethernet had to work hard to make it happen and do a good job.

Will Ethernet have a 50th birthday, or will it be just a memory by the year 2023?

Cooper: Due to its ubiquity, Ethernet will survive as a marketing term and perhaps as an emulated compatibility mode supported by the terabit/sec, combined cell-and-frame, all-switched networks of the year 2023.

Bradner: Just like the person who said: "I don't know what the major programming language will be in the year 2000, but I know it will be called COBOL," I fully expect that a technology called Ethernet will be a major player in networks in the year 2023. But I do not expect that it will be a CSMA/CD-based technology.

Cerf: It's lasted 25 years and gone from 3Mbps to 1000Mbps in that time. If it can reach terahertz through switching methods, it could reach 1,000,000Mbps by 2023, maybe sooner.

Daines: Unless every computer uses teleportation or has ESP built into them by then, yes, I think Ethernet will have a 50th birthday.

Bhardwaj: It depends on what we mean by Ethernet. Ethernet is today full duplex, and that means it is no longer CSMA/CD technology. It is also no longer a shared medium with the advent of switching. So Ethernet will keep on evolving, but it is quite possible that it will be called Ethernet after 50 years even though it will have, in effect, changed from an ape to a human being.

What has most surprised you about the evolution of Ethernet?

Daines: The biggest surprise I had was at Grand Junction when we were working on a 100Mbps Ethernet network interface card that would start selling at about $US1500, which is about what the FDDI ones were. I made the prediction that within a few years we'd get our NIC down to about $US250. Look how wrong I was. It's now between $US30 to $US40 for a 100Mbps NIC.

Bradner: The level of assumption by others - first token ring proponents, then ATM proponents - that Ethernet was a has- been inferior technology and would soon fade to nothing.

Cerf: Its ability to adapt to higher speeds through the switched versions.


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