“以太網(wǎng)絡(luò)(Ethernet)的發(fā)明是靠幕后一群無名工程師的協(xié)助；”Bob Metcalfe 一邊深深吸了口香煙，一邊回憶他在1973年5月22日寫給Xerox PARC同事的備忘錄中，所描述的一種現(xiàn)在已經(jīng)無所不在的網(wǎng)絡(luò)技術(shù)。
當(dāng)煙霧繚繞在他的頭頂，有些人名與故事逐漸從遙遠(yuǎn)的過去浮現(xiàn)；第一個人是史丹佛大學(xué)畢業(yè)的David Boggs，他是1973年時Metcalfe在PARC時的隔壁實(shí)驗(yàn)室同事。“Boggs在我笨拙地試圖剝掉電纜末端的電線外皮以及焊接連接器時幫了我一把，那剛好是他很擅長的工作。”Metcalfe回憶。
以太網(wǎng)絡(luò)的幕后推手之一David Boggs
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1976年，上面這兩個男人與另一位同事Tat Lam，共同打造出后來變成以太網(wǎng)絡(luò)的首個實(shí)驗(yàn)原型，是透過同軸電纜達(dá)到2.94 Mbit/second傳輸速率的一個連結(jié)。
3 Mbit/s 以太網(wǎng)絡(luò)原型
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Lam是一位負(fù)責(zé)開發(fā)點(diǎn)陣式顯示器的模擬工程師，與Metcalfe、Boggs同樣在34號大樓的地下室工作，他幫忙為該原型開制作了收發(fā)器。后來Tam創(chuàng)立了一家銷售以太網(wǎng)絡(luò)收發(fā)器的公司，以他的姓名首字母命名為TCL。
Metcalfe吸了一口煙，又想起一個名字──Ron Crane，這是另一個史丹佛畢業(yè)生，Metcalfe雇用他加入Xerox 團(tuán)隊(duì)，后來創(chuàng)辦那家將以太網(wǎng)絡(luò)推向市場的3Com公司時，又邀請Crane過去擔(dān)任硬件設(shè)計主管。
“Crane主導(dǎo)設(shè)計我們所有早期的以太網(wǎng)絡(luò)產(chǎn)品，并與其它許多人共同協(xié)助發(fā)展IEEE標(biāo)準(zhǔn)；”Metcalfe回憶：“現(xiàn)在對以太網(wǎng)絡(luò)有功的工程師名單開始越來越長了…”
David Boggs、Ron Crane與Robert Metcalfe
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的確，有無數(shù)工程師透過標(biāo)準(zhǔn)組織，協(xié)助推動不同種類的以太網(wǎng)絡(luò)技術(shù)進(jìn)入產(chǎn)品與市場；但這一切始于PC問世之前，PARC聘用Metcalfe開發(fā)一種能將該公司的Alto微電腦產(chǎn)品連成網(wǎng)絡(luò)的方法，而當(dāng)時他是取代先前一位工程師Charles Simonyi的位子。
“當(dāng)我加入PARC，Simonyi轉(zhuǎn)向負(fù)責(zé)開發(fā)一種文字編輯器軟件，后來演變成微軟(Microsoft)的 WORD應(yīng)用程序，他也因此變成億萬富翁，還曾經(jīng)上太空造訪國際太空站兩次?！盡etcalfe又長長地吸了一口煙。
在 1973年寫的備忘錄中，Metcalfe列出對以太網(wǎng)絡(luò)的想法，他構(gòu)想出夏威夷大學(xué)Aloha網(wǎng)絡(luò)的變形，并以其做為哈佛博士論文的一部分研究。 Metcalfe的研究成果有兩大創(chuàng)新，一是以資料碰撞(data collisions)將干擾最小化的算法，其二是能在任何介質(zhì)、甚至是神秘的“以太(Ether)”運(yùn)作的靈活性，后來他也用“以太”來為該技術(shù)命 名。
1973年在PARC工作的Bob Metcalfe
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以太網(wǎng)絡(luò)技術(shù)在IEEE標(biāo)準(zhǔn)組織中，與包括IBM、甚至通用汽車(General Motors)等同樣試圖定義自家網(wǎng)絡(luò)標(biāo)準(zhǔn)的大廠有多場戰(zhàn)斗，在市場上也與其它網(wǎng)絡(luò)技術(shù)斗爭；最后，Metcalfe的概念成為局域網(wǎng)絡(luò)(LAN)的基礎(chǔ)。
Metcalfe 認(rèn)為，以太網(wǎng)絡(luò)的勝利有部分源于“我們所付出的誠意”，那與其它廠商提案動機(jī)是保護(hù)自家傳統(tǒng)業(yè)務(wù)大不相同。而也許更重要的是：“以太網(wǎng)絡(luò)了解自己在通訊層 中扮演的角色，只定義第一層與第二層協(xié)議，并沒有想要做更多；也因?yàn)槿绱?，它比其它競爭技術(shù)簡單、成本也較低?！?
以太網(wǎng)絡(luò)最 終被采用為Wi-Fi以及一系列網(wǎng)絡(luò)技術(shù)的基礎(chǔ)，應(yīng)用領(lǐng)域從工業(yè)控制、到在光通訊核心網(wǎng)絡(luò)中取代Sonet，傳輸速率范圍從3 Mbits/s 至 100 Gbits/s。根據(jù)市場研究機(jī)構(gòu) IDC的統(tǒng)計，在2011年，全球以太網(wǎng)絡(luò)連結(jié)出貨量為12億埠，其中有8億埠是無線通訊應(yīng)用。
“現(xiàn)在的‘以太網(wǎng)絡(luò)’與相同技術(shù) CSMA/CD (Carrier sense multiple access with collision detection，載波偵測與多重存取)其實(shí)相去甚遠(yuǎn)，甚至已經(jīng)不在其范圍內(nèi)；但這個名字被用來展現(xiàn)更大的想法?！盡etcalfe表示：“它可能是封 包格式或者是符合官方標(biāo)準(zhǔn)、競爭激烈的商業(yè)模式，并具備向后兼容能力──我認(rèn)為這是今日人們對以太網(wǎng)絡(luò)的定義?！?
Metcalfe 在去年接下一個新任務(wù)，擔(dān)任美國德州大學(xué)奧斯汀分校的“創(chuàng)新教授(Professor of Innovation)”，他表示：“我的任務(wù)是讓奧斯汀變成另一個更厲害的硅谷，計劃的核心是一所工程學(xué)院，我在那里于協(xié)助工程師創(chuàng)業(yè)；如果你有興趣開 公司，我會告訴你該怎么做?！?
當(dāng)被問到是否有任何他認(rèn)為具未來潛力的無名新人工程師時，Metcalfe吸了最后一口煙，僅表示：“就算有很多人會潑他們冷水，我會為他們每一個人加油打氣。”
本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載
編譯：Judith Cheng
參考英文原文：Metcalfe on Ethernet’s lessons, unsung heros，by Rick Merritt
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Metcalfe on Ethernet’s lessons, unsung heros
Rick Merritt
“There’s an army of unsung engineers who helped invent Ethernet,” says Bob Metcalfe, taking a long drag on his cigarette as he ruminates about the now ubiquitous network technology he described in a memo to colleagues at Xerox PARC on May 22, 1973.
As the smoke curls around his head some of the names and the stories begin to emerge from the distant past. The first is David Boggs, a Stanford grad student who in 1973 was working in the next lab over from Metcalfe at PARC.
Click on image to enlarge.
David Boggs
“Boggs noticed I had trouble skinning and soldering connectors at end of cables and offered to help because it was something he was good at,” Metcalfe recalls.
By 1976 the two men along with another lab partner, Tat Lam, created the first prototype of what was to become Ethernet, a 2.94 Mbit/second link over a coaxial cable.
Click on image to enlarge.
Ethernet 3 Mbit/s prototype
Lam was an analog engineer working on a bit-mapped display in the same basement of Building 34 as Metcalfe and Boggs. He helped create the transceiver for the prototype. Later Tam created a company that sold Ethernet transceivers and bore his initials, TCL, before disappearing from Metcalfe’s sight like so much cigarette smoke.
Note: Bob Metcalfe says he does not smoke and never has. The interview was conducted via phone and the reporter mistakenly thought he heard sounds of smoking.
The Crane connection
Another drag, another name. Ron Crane, another Stanford grad student. Metcalfe hired Crane for his Xerox team and later recruited him as a hardware guru at 3Com, the company Metcalfe built to take Ethernet to the market. “Crane led the design of all our early Ethernet products and helped develop the IEEE standard” along with many others, Metcalfe recalled. “The list starts getting long now,” he said.
Click on image to enlarge.
David Boggs, Ron Crane and Robert Metcalfe
Indeed, hundreds of engineers have helped drive various flavors of Ethernet through standards bodies, into products and out to the market. It all began when PARC hired Metcalfe to find a way to network the Alto microcomputers it built in the days before the PC. He wound up unseating another engineer who previously had that charter, Charles Simonyi.
In a twist of fate, “when I came Simonyi switched to developing a text editor which over time evolved into Microsoft Word and made him a billionaire who has since visited the International Space Station twice,” said Metcalfe, taking another long draw on his cigarette.
In his 1973 memo, Metcalfe outlined his thoughts on Ethernet. He conceived a variation of the Aloha Network at the University of Hawaii he studied as part of a Harvard doctoral thesis. It sported two innovations — an algorithm that uses data collisions to minimize interference and the flexibility to run over any medium, even the mythical Ether for which he named it.
Click on image to enlarge.
Bob Metcalfe at PARC 1973
There were plenty of fights along the way in IEEE standards groups with giants like IBM and even General Motors who tried to define their own networks--and fights in the market trying to establish those technologies and others.
In the end, Metcalfe’s concepts became the basis for local area networks. Ethernet won in part “due to the sincerity of our efforts,” as opposed to the motivations of other proposals trying to protect legacy businesses, Metcalfe claims.
Perhaps more importantly, “Ethernet understands its role in the comms hierarchy, it was a Layer 1-2 protocol and didn’t try to do more than that,” he said. “As a result it is simpler and cheaper than the alternatives because it only did want it needed and not more,” he added.
Ultimately Ethernet was adopted as the basis for Wi-Fi and a wide range of nets that now span everything from industrial controls to optical telco core networks where it is replacing Sonet. It has evolved from 3 Mbits/s to 100 Gbits/s. Last year, vendors shipped 1.2 billion Ethernet connections, 800 million of them wireless ones, according to International Data Corp.
“It’s not even close to the same technology — CSMA/CD [Carrier sense multiple access with collision detection, one of Metcalfe’s early innovations] isn’t even in it anymore, but the name is used to embody a bigger idea,” Metcalfe said. “It could be the packet format or the business model of a de jure standard with fierce competition and backward compatibility -- that business model is I think what people mean by Ethernet, today,” he said.
Last year, Metcalfe took up a new job as Professor of Innovation at the University of Texas in Austin.
“My mission is to help make Austin a better Silicon Valley, and the core of that is an engineering school where I’m focused on helping engineers who want to start companies,” said Metcalfe. “If you are interested in starting a company, it’s my job to show you how to do it,” he said.
We asked if there are any unsung up-and-coming engineers he wanted to name.
“I am rooting for them all. There are plenty of people who will discourage them,” he said taking a last pull on his cigarette.
責(zé)編：Quentin
