962 lines
53 KiB
Plaintext
962 lines
53 KiB
Plaintext
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From: "gordon jacobson" <gordon.jacobson@channel1.com>
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Date: 16-Mar-93 00:46:12
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Subj: into the fibersphere
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Newsgroups: alt.dcom.telecom
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Organization: Channel 1 Communications
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I have seen references to the following article in this and other
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newsgroups. I contacted the author and Forbes and as the preface
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below indicates obtained permission to post on the Internet. Please
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note that the preface must be included when cross posting this article
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to another newsgroup.
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The following was received directly from George Gilder on Saturday March 6.
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-----------------
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Date: Sat Mar 06, 1993 2:58 pm GMT
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From: George Gilder / MCI ID: 409-1174
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TO: Gordon Jacobson
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Subject: PLEASE UPLOAD TO INTERNET
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The following article, INTO THE FIBERSPHERE, was first published in
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slightly different and shorter form in Forbes ASAP, December 7, 1993. It
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is a portion of my book, Telecosm, which will be published next year by
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Simon & Schuster, as a sequel to Microcosm, published in 1989 and Life
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After Television published by Norton in 1992. Subsequent chapters of
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Telecosm will be serialized in Forbes ASAP beginning with the March issue
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containing a theory of wireless communications.
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PLEASE POST "FIBERSPHERE" TO ANY USENET
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NEWSGROUPS THAT MAY BE DEEMED SUITABLE.
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THE COMING OF THE FIBERSPHERE
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In a world of dumb terminals and telephones,
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networks had to be smart. But in a world of
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smart terminals, networks have to be dumb.
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BY
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GEORGE GILDER
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Philip Hope, divisional vice president for engineering systems of EDS,
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has an IQ problem. His chief client and owner, General Motors, wants to
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interconnect thousands of 3-D graphics and computer aided engineering (CAE)
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workstations with mainframes and supercomputers at Headquarters, with
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automated assembly equipment at factories in Lordstown, Indiana, and
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Detroit, with other powerful processors at their technical center in
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Warren, Michigan, with their Opel plant in Ruesselheim, Germany, and with
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their design center outside San Diego. On behalf of another client, Hope
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wants to link multimedia stations for remote diagnostics, X-ray analysis,
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and pharmaceutical modeling in hospitals and universities across the
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country.
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Any function involving 3-D graphics, CAE, supercomputer visualization,
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lossless diagnostic imaging, and advanced medical simulations demands large
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bandwidth or communications power. Graphics workstations often operate
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screens with a million picture elements (pixels), and use progressive
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scanning at 60 frames or images a second. Each pixel may entail 24 bits of
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color. That adds up fast to billions of bits (gigabits) a second. And
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that's for last year's technology in a computer industry that is doubling
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its powers and cost effectiveness every year.
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What Hope needs is bandwidth and connections. The leading bandwidth
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and connections people have always been the telephone companies. But when
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Hope goes to the telephone companies, they want to tell him about
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intelligence: their Advanced Intelligent Network which will be coming on
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line over the next decade or so and will solve all his problems. For now,
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they have what they call DS-3 services available in many areas, operating
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T-3 lines at 45 megabits (million bits) a second. These facilities are
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ample for most computer uses and working together with several different
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Regional Bell Operating Companies (RBOCs), Hope should be able to acquire
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these services in time for a General Motors takeover by Toyota.
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Hope has been through this before. In the early 1980s, he actually
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wanted D-3 services. Then he was interconnecting facilities in Southeast,
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Michigan, with plants in Indiana and Ohio. But Michigan Bell could not
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supply the lines in time. EDS had to build a network of microwave towers
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to bear the 45 megabit traffic. Later in the decade, the phone companies
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have even offered him higher capacity fiber optic lines, with the
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requirement that the optical bits be slowed down and run periodically
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through an electronic interface so the telco could count the number of
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"equivalent channels" being used.
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What Hope and others in the systems integration business need is not
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intelligent networks tomorrow but dumb bandwidth that they can deliver to
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their customers flexibly, cheaply, and now. To prepare for future demand,
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they want the network to use fiber optics. It so happens that America's
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telephone companies have some two million miles of mostly unused fiber
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lines in the ground today, kept as redundant capacity for future needs.
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Hope would like to be able to tap into this "dark fiber" for his own
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customers.
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As a leader in the rapidly expanding field of computer services, EDS
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epitomizes the needs of an information economy. With a backlog of 22
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billion dollars in already contracted business, EDS is currently a seven
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billion dollar company growing revenues at an annual rate of 15 percent,
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some three times as fast as the phone companies. EDS will add a billion
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dollars or so in new sales in 1992 alone. If the company is to continue to
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supply leading edge services to its customers, it must command leading edge
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communications. To EDS, that means dumb and dark networks.
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THE "DARK FIBER" CASE
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That need has driven EDS into an active role as an ex parte pleader in
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Federal Case 911416, currently bogging down in the District of Columbia
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Federal Court of Appeals as the so-called "dark fiber" case. On the
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surface, the case, known as Southwestern Bell et al versus the Federal
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Communications Commission and the U.S. Justice Department, pits four
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Regional Bell telephone companies against the FCC. But the legal maneuvers
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actually reflect a rising conflict between the Bells and several large
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corporate clients over the future of communications.
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Beyond all the legal posturing, the question at issue is whether fiber
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networks should be dumb and dark, and cheap, the way EDS and other
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customers like them. Or whether they should be bright and smart, and
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"strategically" priced, the way the telephone companies want them.
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On the side of intelligence and light are the phone companies;
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Southwestern Bell, U.S. West, Bell South, and Bell Atlantic. The forces of
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darkness include key officials at the FCC and such companies as Shell Oil,
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the information services arm of McDonald Douglas, long distance network
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provider Wiltel, as well as EDS.
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For most of the four year course of the struggle, it has passed
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unnoticed by the media. In summary, the issue may not seem portentous.
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The large corporate customers want dark fiber; the FCC mandates that it be
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supplied; the Bells want out of the business. But for all their obscurity,
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the proceedings raise what for the next twenty years will be the central
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issue in communications law and technology. The issue, if not the possible
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trial itself, will shape the future of both the computer and telephone
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industries during a period when they are merging to form the spearhead of a
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new information economy.
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"Dark fiber" is simply a glass fiber optic thread with nothing
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attached to it, (ie. no light being sent through it). In this "unlit"
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condition, it is available for use without the intermediation of phone
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company electronics or intelligent services.
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In the mid-1980s, the Bells leased some of their dark fiber lines to
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several large corporations on an individual case basis. These companies
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learned to love dark fiber. But when they tried to renew their leases with
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the Bells, the Bells clanged no! Why don't you leave the interconnections
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and protocols to us? Why don't you use our marvellous smart network with
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all the acronyms and intelligent services? Why don't you let us meter your
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use of the fiber and send you a convenient monthly bill for each packet of
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bits you send?
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EDS and the other firms rejected the offer; they preferred that dumb
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fiber to the intelligent network. When the Bells persisted in an effort to
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deny new leases, the companies went to the FCC to require the Bells, as
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regulated "common carrier" telephone companies, to continue supplying dark
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fiber.
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In the fall of 1990, the FCC ruled that the phone companies would have
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to offer dark fiber to all comers under the rules of common carriage.
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Rather than accept this new burden, the phone companies petitioned to
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withdraw from the business entirely under what is called a rule 214
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application. Since the FCC has not acted on this petition, the Bells are
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preparing to go to court to force the issue. Their corporate customers are
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ready to litigate as well.
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It is safe to say that none of the participants fully comprehend the
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significance of their courthouse confrontation. To the Bells, after all is
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said and done, the key problem is probably the price. Under the existing
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tariff, they are required to offer this service to anyone who wants it for
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an average price of approximately $150 per strand of fiber per month. As
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an offering that competes with their T-3 45 megabit (millions of bits) a
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second lines and other forthcoming marvels, dark fiber threatens to gobble
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up their future as vendors of broadband communications to offices, even as
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cable TV preempts them as broadband providers to homes. Since the Bells'
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profits on data are growing some 10 times as fast as their profits on voice
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telephony, they see dark fiber as a menace to their most promising markets.
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The technological portents, however, are far more significant even
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than the legal and business issues. The coming triumph of dark fiber will
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mean not only the end of the telephone industry as we know it but also the
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end of the telephone industry as they plan it: a vast intelligent fabric
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of sophisticated information services. It also could mean a thoroughgoing
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restructuring of a computer industry increasingly dedicated to supplying
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"smart networks." Indeed, for most of the world's communications companies,
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professors of communications theory, and designers of new computer
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networks, the triumph of dark and dumb means "back to the drawing board,"
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if not back to the dark ages.
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But the new dark ages cannot be held back.
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Springing out the depths of IBM's huge Watson Laboratories is a
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powerful new invention: the all optical network, that will soon relegate
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all bright and smart executives to the Troglodyte file and make dumb and
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dark the winning rule in communications.
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THE WRINGER EFFECT
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From time to time, the structure of nations and economies goes through
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a technological wringer. A new invention radically reduces the price of a
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key factor of production and precipitates an industrial revolution. Before
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long, every competitive business in the economy must wring out the residue
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of the old costs and customs from all its products and practices.
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The steam engine, for example, drastically reduced the price of
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physical force. Power once wreaked at great expense from human and animal
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muscle pulsed cheaply and tirelessly from machines burning coal and oil.
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Throughout the world, dominance inexorably shifted to businesses and
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nations that reorganized themselves to exploit the suddenly cheap resource.
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Eventually every human industry and activity, from agriculture and sea
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transport to printing and war, had to centralize and capitalize itself to
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take advantage of the new technology.
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Putting the world through the technological wringer over the last
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three decades has been the integrated circuit, the IC. Invented by Robert
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Noyce of Intel and Jack Kilby of Texas Instruments in 1959, the IC put
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entire systems of tiny transistor switches, capacitors, resistors, diodes,
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and other once costly electronic devices on one tiny microchip. Made
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chiefly of silicon, aluminum, and oxygen, three of the most common
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substances on earth, the microchip eventually reduced the price of
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electronic circuitry by a factor of a million.
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As industry guru Andrew Rappaport has pointed out, electronic
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designers now treat transistors as virtually free. Indeed, on memory
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chips, they cost some 400 millionths of a cent. To waste time or battery
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power or radio frequencies may be culpable acts, but to waste transistors
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is the essence of thrift. Today you use millions of them slightly to
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enhance your TV picture or to play a game of solitaire or to fax Doonsbury
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to Grandma. If you do not use transistors in your cars, your offices, your
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telephone systems, your design centers, your factories, your farm gear, or
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your missiles, you go out of business. If you don't waste transistors,
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your cost structure will cripple you. Your product will be either too
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expensive, too slow, too late, or too low in quality.
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Endowing every information age engineer or PC hacker with the creative
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potential of a factory owner of the industrial age, the microchip reversed
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the centralizing thrust of the previous era. All nations and businesses
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had to adapt to the centrifugal law of the microcosm, flattening
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hierarchies, outsourcing services, liberating engineers, shedding middle
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management. If you did not adapt your business systems to the new regime,
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you would no longer be a factor in the world balance of economic and
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military power.
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During the next decade or so, industry will go through a new
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technology wringer and submit to a new law: the law of the telecosm. The
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new wringer, the new integrated circuit, is called the all optical network.
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It is a communications system that runs entirely in glass. Unlike existing
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fiber optic networks, which convert light signals to electronic form in
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order to amplify or switch them, the all optical network is entirely
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photonic. From the first conversion of the signal from your phone or
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computer to the final conversion to voice or data at the destination, your
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message flies through glass on wings of light.
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Just as the old integrated circuit put entire electronic systems on
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single slivers of silicon, the new IC will put entire communications
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systems on seamless webs of silica. Wrought in threads as thin as a human
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hair, this silica is so pure that you could see through a window of it
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seventy miles thick. But what makes the new wringer roll with all the
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force of the microchip revolution before it is not the purity but the
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price. Just as the old IC made transistor power virtually free, the new
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IC, the all optical network, will make communications power virtually free.
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Another word for communications power is bandwidth. Just as the
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entire world had to learn to waste transistors, the entire world will now
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have to learn how to waste bandwidth. In the 1990s and beyond, every
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industry and economy will go through the wringer again.
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The impact on the organization of companies and economies, however,
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has yet to become clear. What is the law of the telecosm? Will the new
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technology reverse the centrifugal force of the microchip revolution...or
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consummate it? To understand the message of the new regime, we must follow
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the rule of microcosmic prophet Carver Mead of Caltech: "Listen to the
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technology...and find out what it is telling us."
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THE SHANNON-SHOCKLEY REGIME
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The father of the all-optical-network, the man who coined the phrase,
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built the first fully functional system, and wrote the definitive book on
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the subject, is Paul E. Green, Jr. of Watson Laboratory at IBM. Now
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standing directly in the path of Green's wringer is Robert Lucky, who some
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seven years ago at a conference at Cornell first gave Green the idea that
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an all optical network might be possible.
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The leading intellectual in telephony, Lucky recently shocked the
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industry by shifting from AT&T's Bell Labs, where he was executive director
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of research, to Bellcore, the laboratory of the Regional Bell Operating
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Companies (RBOCs). There he will soon have to confront the implications of
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Green's innovation.
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Contemplating the new technology, Lucky recalls a course on data
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networks that he used to teach many years ago with Green. As a computer
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man, Green relished the contrast between the onrushing efficiencies in his
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technology and the relative dormancy in communications. Indeed, for some
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twenty five years, while computer powers rose a millionfold, network
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capacities increased about a thousandfold. It was not until the late 1980s
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that most long distance data networks much surpassed the Pentagon's
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"ARPANET" running at 50 kilobits (thousands of bits) per second since the
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mid sixties.
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This was the era dominated by the powerful mathematic visions and
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theories of Claude Shannon of MIT and Bell Labs. Shannon was the reclusive
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genius who invented Information Theory to ascertain the absolute carrying
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capacity of any communications channel.
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Whether wire or air, channels were assumed to be narrow and noisy, the
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way God made them (sometimes with help from AT&T). Typical were the copper
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phone lines that still link every household to the telephone network and
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the air waves that still bear radio and television signals and static.
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The all-purpose remedy for these narrow, noisy channels was powerful
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electronics. Invented at Bell Laboratories by a team headed by William
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Shockley and then developed by Robert Noyce and other Shockley proteges in
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Silicon Valley, silicon transistors and integrated circuits engendered a
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constant exponential upsurge of computing power.
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Throwing ever more millions of ever faster and cheaper transistors at
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every problem, engineers created fast computers, multiplexors, and switches
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that seemed to surmount and outsmart every limit of bandwidth or
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restriction of wire. This process continues today with heroic new
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compression tools that allow the creation of full video conferences over 64
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kilobit telephone connections. Scientists at Bellcore are now even
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proposing new ways of using the Motion Picture Engineering Group (MPEG)
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compression standard to send full motion movies at 1.5 megabits a second
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over the 4 kilohertz twisted pair copper wires to the home. Using ever
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faster computers, the telephone company is saying it can give you pay-per-
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view movies without installing fiber, or even coaxial cable, to the home.
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In the Shannon-Shockley era, the communications might be noisy and
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error prone, but smart electronics could encode and decode messages in
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complex ways that allowed efficient identification and correction of all
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errors. The Shannon channel might be narrow, but fast multiplexors allowed
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it to be divided into time slots accommodating a large number of
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simultaneous users in a system called time division multiplexing. The
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channel might clog up when large numbers of users attempted to communicate
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with each other at once, but collision detectors or token passers could
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sort it all out in nanoseconds. Graphics and video might impose immense
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floods of bits on the system, but compression technology could reduce the
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floods to a manageable trickle with little or no loss of picture quality.
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If all else failed, powerful electronic switches could compensate for
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almost any bandwidth limitations. Switching could make up for the
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inadequate bandwidth at the terminals by relieving the network of the need
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to broadcast all signals to every destination. Instead, the central switch
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could receive all signals and then route them to their appropriate
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addresses.
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To this day, this is the essential strategy of the telephone
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companies: compensate for narrow noisy bandwidth with ever more powerful
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and intelligent digital electronics. Their "core competence," the Bells
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hasten to tell you, is switching. They make up for the shortcomings of
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copper wires by providing smart, powerful digital switches.
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Their vision for the future is to join the computer business all the
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way, making these switches the entering wedge for ever more elaborate
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information services. Switches will grow smarter and more sophisticated
|
||
|
until they provide an ever growing cornucopia of intelligent voice and fax
|
||
|
features, from caller ID and voice mail to personal communications systems
|
||
|
that follow you and your number around the world from your car commute to
|
||
|
your vacation beach hideaway. In the end, these intelligent networks could
|
||
|
supply virtually all the world's information needs, from movies, games and
|
||
|
traffic updates to data libraries, financial services, news programs, and
|
||
|
weather reports, all climaxing with yellow pages that exfoliate into a
|
||
|
gigantic global mall of full motion video where your fingers walk (or your
|
||
|
voice commands echo) from Harrods, to Jardines, to Akihabara, to Century 21
|
||
|
without you leaving the couch.
|
||
|
|
||
|
At the time when Green and Lucky taught their course, this strategy
|
||
|
for the future was only a glimmer in the minds of telephone visionaries.
|
||
|
|
||
|
But the essence of it was already in place. As Green pointed out,
|
||
|
telephone companies' response to sluggishness in communications was to
|
||
|
enter the computer industry, where progress was faster. The creativity of
|
||
|
digital electronics would save the telephone industry from technical
|
||
|
stagnation.
|
||
|
|
||
|
Lucky, however, protested to Green that it was unjust to compare the
|
||
|
two fields. Computers and telecom, as Lucky explained it, operate on
|
||
|
entirely different scales. Computers work in the microscale world of the
|
||
|
IC, putting ever more thousands of wires and switches on single slivers of
|
||
|
silicon.
|
||
|
|
||
|
By contrast, telecommunications functions in the macroworld, laying
|
||
|
out wires and switches across mostly silicon landscapes and seabeds. It
|
||
|
necessarily entails a continental, or even intercontinental stretch of
|
||
|
cables, microwave towers, switches, and poles. "How was it possible,"
|
||
|
Lucky asked, "to make such a large scale system inexpensive?" Inherent in
|
||
|
the structure and even the physics of computers and telecommunications, so
|
||
|
it seemed to Lucky two decades ago, was a communications bottleneck.
|
||
|
|
||
|
As Lucky remembers it, Green was never satisfied with Lucky's point.
|
||
|
Green believed that someday communications could achieve miracles
|
||
|
comparable to the integrated circuit in computing....
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
THE BANDWIDTH SCANDAL
|
||
|
|
||
|
|
||
|
|
||
|
Today, as Lucky was the first to announce, fiber optics has utterly
|
||
|
overthrown the previous relationship between fast computers and slow wires.
|
||
|
Now it is computer technology that imposes the bottleneck on the vast
|
||
|
vistas of dark fiber.
|
||
|
|
||
|
A silicon transistor can change its state some 2.5 billion times a
|
||
|
second in response to light pulses (bundles of photons) hitting a photo-
|
||
|
detector. Since it would take a human being a thousand years or so of 10
|
||
|
hour workdays even to count to two billion, two billion cycles in a single
|
||
|
second (two gigahertz) might seem a sprightly pace. But in the world of
|
||
|
fiber optics running at the speed and frequencies of light, even a rate of
|
||
|
two billion cycles a second is a humbling bow to the slothful pace of
|
||
|
electronics. Since optical signals still have to be routed to their
|
||
|
destinations through computer switches, communications now suffers from
|
||
|
what is known as the "electronic bottleneck."
|
||
|
|
||
|
It is this electronic bottleneck, the entire Bell edifice of Shannon
|
||
|
and Shockley, that Paul Green plans to blow away with his all optical
|
||
|
networks. Green is targeting what is a secret scandal of modern
|
||
|
telecommunications: the huge gap between the real capacity of fiber optics
|
||
|
and the actual speed of telephone communications.
|
||
|
|
||
|
In communications systems, the number of waves per second (or hertz)
|
||
|
represents a rough measure of its potential bandwidth or ultimate carrying
|
||
|
capacity. The bandwidth of a radio system, for example, is determined by
|
||
|
the frequency of each station or channel and by the number of stations that
|
||
|
can fit within the band. Your AM dial, for example, runs from around 535
|
||
|
thousand hertz (kilohertz) to 1705 kilohertz and each station uses some 10
|
||
|
kilohertz. With an ideal receiver, the AM passband might carry 117
|
||
|
stations.
|
||
|
|
||
|
By contrast, the intrinsic bandwidth of one strand of dark fiber is
|
||
|
some 25 thousand gigahertz in each of three groups of frequencies (three
|
||
|
passbands) through which fiber can transmit light over long distances. At
|
||
|
a gigahertz per terminal, this bandwidth might accommodate some 25,000
|
||
|
supercomputer "stations" (or 2.5 billion AM stations). Using what is
|
||
|
called dispersion shifted fiber, it may be possible to use two of these
|
||
|
passbands at once: a total of some 40 or 50 thousand gigahertz. For
|
||
|
comparison, consider all the radio frequencies currently used in the air
|
||
|
for radio, television, microwave, and satellite communications and multiply
|
||
|
by two thousand. The bandwidth of one fiber thread could carry more than
|
||
|
two thousand times as much information as all these radio and microwave
|
||
|
frequencies that currently comprise the "air." One fiber thread could bear
|
||
|
twice the traffic on the phone network during the peak hour of Mothers' Day
|
||
|
in the U.S. (the heaviest load currently managed by the phone system).
|
||
|
|
||
|
Yet even for point-to-point long distance links, let alone connections
|
||
|
to homes, telephone and computer network engineers now turn their backs on
|
||
|
this immense capacity and use perhaps one or two fifty thousandths it.
|
||
|
Deferring to the electronic bottleneck, the telephone industry uses fiber
|
||
|
merely as a superior replacement for the copper wires, coaxial cables,
|
||
|
satellite links, and microwave towers that connected the local central
|
||
|
office switches to one another for long distance calls.
|
||
|
|
||
|
Over the last 15 years, the Bell Laboratory record for fiber optics
|
||
|
communication has run from 10 megabits per second over a one kilometer span
|
||
|
to some 10 gigabits per second over nearly one thousand kilometers. But
|
||
|
all the heroic advances in point-to-point links between central offices
|
||
|
continued to use essentially one frequency on a fiber thread, while
|
||
|
ignoring its intrinsic power to accommodate thousands of useful
|
||
|
frequencies.
|
||
|
|
||
|
In a world of all optical networks, this strategy is bankrupt. No
|
||
|
longer will it be possible to throw more transistors, however cheap and
|
||
|
fast, at the switching problem. Electronic speeds have become an
|
||
|
insuperable bottleneck obstructing the vast vistas of dark fiber beyond.
|
||
|
|
||
|
So called gigabit networks planned by the telephone and computer
|
||
|
companies will not do. What is needed is not a gigabit spread among many
|
||
|
terminals, but a large network functioning at a gigabit per second per
|
||
|
terminal.
|
||
|
|
||
|
The demands of EDS offer a hint of the most urgent business needs.
|
||
|
Added to them will be consumer demands. True high definition television,
|
||
|
comparable to movies in resolution, requires close to gigabit-a-second
|
||
|
bandwidth, particularly if the program is dispatched to the viewer in burst
|
||
|
mode all at once in a few seconds down the fiber, or if the user is given a
|
||
|
chance to shape the picture, choose a vantage point, window several images
|
||
|
at once, or experience three dimensions. When true broadband channels
|
||
|
become available, there will be a flood of new applications comparable to
|
||
|
the thousands of new uses of the IC.
|
||
|
|
||
|
No foreseeable progress in electronics can overcome the electronic
|
||
|
bottleneck. To do that, we need an entirely new communications regime. In
|
||
|
the form of the all optical network, this regime is now at hand.
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
LAW OF THE TELECOSM: NETWORKS DUMB AS A STONE
|
||
|
|
||
|
|
||
|
The new regime will use fiber not as a replacement for copper wires
|
||
|
but as a new form of far more capacious and error-free air. Through a
|
||
|
system called wavelength division multiplexing and access, computers and
|
||
|
telephones will tune into desired messages in the fibersphere the same way
|
||
|
radios now tune into desired signals in the atmosphere. The fibersphere
|
||
|
will be intrinsically as dumb and dark as the atmosphere.
|
||
|
|
||
|
The new regime overcomes the electronic bottleneck by altogether
|
||
|
banishing electronics from the network. But, ask the telcos in unison,
|
||
|
what about the switches? As long as the network is switched, it must be
|
||
|
partly electronic. Unless the network is switched, it is not a true any-
|
||
|
to-any network. It is a broadcast system. It may offer a cornucopia of
|
||
|
services. But it cannot serve as a common carrier like the phone network
|
||
|
allowing any party to reach any other. Without intelligent switching it
|
||
|
cannot provide personal communications nets that can follow you wherever
|
||
|
you go. Without intelligent switching, the all optical network, so they
|
||
|
say, is just a glorified cable system.
|
||
|
|
||
|
These critics fail to grasp a central rule of the telecosm: bandwidth
|
||
|
is a nearly perfect substitute for switching. With sufficient physical
|
||
|
bandwidth, it is possible to simulate any kind of logical switch
|
||
|
whatsoever. Bandwidth allows creation of virtual switches that to the user
|
||
|
seem to function exactly the way physical switches do. You can send all
|
||
|
messages everywhere in the network, include all needed codes and
|
||
|
instructions for correcting, decrypting, and reading them, and allow each
|
||
|
terminal to tune into its own messages on its own wavelength, just like a
|
||
|
two-way radio. When the terminals are smart enough and the bandwidth great
|
||
|
enough, your all optical network can be as dumb as a stone.
|
||
|
|
||
|
Over the last several years, all optical network experiments have been
|
||
|
conducted around the world, from Bellcore in New Jersey to NTT at Yokosuka,
|
||
|
Japan. British Telecom has used wavelength division multiplexing to link
|
||
|
four telephone central offices in London. Columbia's Telecom Center has
|
||
|
launched a "Teranet" that lacks tunable lasers or receivers but can
|
||
|
logically simulate them. Bell Laboratories has generated most of the
|
||
|
technology but as a long distance specialist has focussed on the project of
|
||
|
sending gigabits of information thousands of miles without amplifiers. But
|
||
|
only fully functional system is the Rainbow created by Paul Green at IBM.
|
||
|
|
||
|
As happens so often in this a world of technical disciplines sliced
|
||
|
into arbitrary fortes and fields, the large advances come from the
|
||
|
integrators. Paul Green is neither a laser physicist, nor an optical
|
||
|
engineer, nor a telecommunications theorist. At IBM, his work has ranged
|
||
|
from overseeing speech recognition projects at Watson Labs to shaping
|
||
|
company strategy at corporate headquarters in Armonk. His most recent
|
||
|
success was supervising development of the new APPN (Advanced Peer to Peer
|
||
|
Network) protocol. According to an IBM announcement in March, APPN will
|
||
|
replace the venerable SNA (systems network architecture) that has been
|
||
|
synonymous with IBM networking for more than a decade.
|
||
|
|
||
|
Green took some pride in this announcement, but by that time, the
|
||
|
project was long in his past. He was finishing the copy editing on his
|
||
|
magisterial tome on Fiber Optic Networks (published this summer by Prentice
|
||
|
Hall). And he was moving on to more advanced versions of the Rainbow which
|
||
|
he and his team had introduced in December 1991 at the Telecom 91
|
||
|
Conference in Geneva and which has been installed between the various
|
||
|
branches of Watson Laboratories in Westchester County, N.Y.
|
||
|
|
||
|
As Peter Drucker points out, a new technology cannot displace an old
|
||
|
one unless it is proven at least 10 times better. Otherwise the billions
|
||
|
of dollars worth of installed base and thousands of engineers committed to
|
||
|
improving the old technology will suffice to block the new one. The job of
|
||
|
Paul Green's 15 man team at IBM is to meet that tenfold test.
|
||
|
|
||
|
Green's all optical network creates a fibersphere as neutral and
|
||
|
passive as the atmosphere. It can be addressed by computers the same way
|
||
|
radios and television sets connect to the air. Consisting entirely of
|
||
|
unpowered glass and passive spitters and couplers, the fibersphere is dark
|
||
|
and dumb. Any variety of terminals can interconnect across it at the same
|
||
|
time using any protocols they choose.
|
||
|
|
||
|
Just as radios in the atmosphere, computer receivers connected to the
|
||
|
fibersphere do not find a series of bits in a message; they tune into a
|
||
|
wavelength or frequency. Because available Fabry Perot tunable filters
|
||
|
today have larger bandwidth than tunable lasers, Green chose to locate
|
||
|
Rainbow's tuning at the receiver and have transmitters each operate at a
|
||
|
fixed wavelength. But future networks can use any combination of tunable
|
||
|
equipment at either end.
|
||
|
|
||
|
When Green began the project in 1987, the industry stood in the same
|
||
|
general position as the pioneers of radio in the early years of that
|
||
|
industry. They had seemingly unlimited bandwidth before them, but lacked
|
||
|
transmitters and receivers powerful enough to use it effectively. Radio
|
||
|
transmitters suffered "splitting losses" as they broadcast their signals
|
||
|
across the countryside. Green's optical messages lose power everytime they
|
||
|
are split off to be sent to another terminal or are tapped by a receiver.
|
||
|
|
||
|
The radio industry solved this problem by the development of the
|
||
|
audion triode amplifier. Green needed an all optical amplifier to replace
|
||
|
the optoelectronic repeaters that now constitute the most widespread
|
||
|
electronic bottleneck in fiber. Amplifiers in current fiber networks first
|
||
|
convert the optical signal to an electronic signal, enhance it, and then
|
||
|
convert it back to photons.
|
||
|
|
||
|
Like the pioneers of radio, Green soon had his amplifier in hand.
|
||
|
Following concepts pioneered by David Payne at the University of
|
||
|
Southhampton in England, a Bell Laboratories group led by Emmanuel
|
||
|
Desurvire and Randy Giles developed a workable all optical device. They
|
||
|
showed that a short stretch of fiber doped with erbium, a rare earth
|
||
|
mineral, and excited by a cheap laser diode, can function as a powerful
|
||
|
amplifier over the entire wavelength range of a 25,000 gigahertz system.
|
||
|
Today such photonic amplifiers enhance signals in a working system of links
|
||
|
between Naples and Pomezia on the west coast of Italy. Manufactured in
|
||
|
packages between two and three cubic inches in size, these amplifiers fit
|
||
|
anywhere in an optical network for enhancing signals without electronics.
|
||
|
|
||
|
This invention overcame the most fundamental disadvantage of optical
|
||
|
networks compared to electronic networks. You can tap into an electronic
|
||
|
network as often as desired without weakening the voltage signal. Although
|
||
|
resistance and capacitance will weaken the current, there are no splitting
|
||
|
losses in a voltage divider. Photonic signals, by contrast, suffer
|
||
|
splitting losses every time they are tapped; they lose photons until
|
||
|
eventually there are none left. The cheap and compact all optical
|
||
|
amplifier solves this problem.
|
||
|
|
||
|
Not only did Green and his IBM colleagues create working all optical
|
||
|
networks, they also reduced the interface optoelectronics to a single
|
||
|
microchannel plug-in card that can fit in any IBM PS/2 level personal
|
||
|
computer or R6000 workstation. Using off-the-shelf components costing a
|
||
|
total of $16,000 per station, Rainbow achieved a capacity more than 90
|
||
|
times greater than FDDI at an initial cost merely four times as much.
|
||
|
|
||
|
Just as Jack Kilby's first ICs were not better than previous adders
|
||
|
and oscillators, the Rainbow I is not better in some respects than rival
|
||
|
networks based on electronics. At present it connects only 32 computers at
|
||
|
a speed of some 300 megabits per second, for a total bandwidth of 9.5
|
||
|
gigabits. This rate is huge compared to most other networks, but it is
|
||
|
still well below the target of a system that provides gigabit rates for
|
||
|
every terminal.
|
||
|
|
||
|
A more serious limitation is the lack of packet switching. Rather
|
||
|
than communicating down a dedicated connection between two parties, like
|
||
|
phones do, computer networks send data in small batches, called packets,
|
||
|
each bearing its own address. This requires switching back and forth
|
||
|
between packets millions of times a second. Neither the current Rainbow's
|
||
|
lasers nor its filters can tune from one message to another more than
|
||
|
thousands of times a second. This limitation is a serious problem for
|
||
|
links to mainframes and supercomputers that may do many tasks at once in
|
||
|
different windows on the screen and with connections to several other
|
||
|
machines.
|
||
|
|
||
|
As Green shows, however, all these problems are well on the way to
|
||
|
solution. A tide of new interest in all optical systems is sweeping
|
||
|
through the world's optical laboratories. The Pentagon's Defense Advanced
|
||
|
Projects Agency (DARPA) has launched a program for all optical networking.
|
||
|
With Green installed as the new President of the IEEE Communications
|
||
|
Society, the technical journals are full of articles on new wavelength
|
||
|
division technology. Every few months brings new reports of a faster laser
|
||
|
with a broader bandwidth, or filter with faster tuning, or an ingenious new
|
||
|
way to use bandwidth to simulate packet switching. Today lasers and
|
||
|
receivers can switch fast enough but they still lack the ability to cover
|
||
|
the entire bandwidth needed.
|
||
|
|
||
|
The key point, however, is that as demonstrated both in Geneva and
|
||
|
Armonk, the Green system showed the potential efficiency of all optical
|
||
|
systems. Even in their initial forms they are more cost effective in
|
||
|
bandwidth per dollar than any other network technology. Scheduled for
|
||
|
introduction within the next two years, Rainbow III will comprise a
|
||
|
thousand stations operating at a gigabit a second, with the increasingly
|
||
|
likely hope of fast packet switching capability. At that point, the system
|
||
|
will be a compelling commercial product at least hundreds of times more
|
||
|
cost effective than the competition.
|
||
|
|
||
|
Without access to dark fiber, however, these networks will be
|
||
|
worthless. If the telephone companies fail to supply it, they risk losing
|
||
|
most of the fastest growing parts of their business: the data traffic
|
||
|
which already contributes some 50 percent of their profits. But there is
|
||
|
also a possibility that they will lose much of their potential consumer
|
||
|
business as well: the planned profits in pay-per-view films and electronic
|
||
|
yellow pages. This is the message of a second great prophet of dark fiber,
|
||
|
Will Hicks of Southbridge, Massachusetts.
|
||
|
|
||
|
A venerable inventor of scores of optical products, Hicks believes
|
||
|
that Green's view of the future of fiber is too limited. Using wavelength
|
||
|
division, Hicks can see the way to deliver some 500 megahertz two-way
|
||
|
connections to all the homes in America for some $400 per home. That is
|
||
|
fifty times the 10 megahertz total capacity of an Ethernet (with no one
|
||
|
else using it) for some 20 percent of the cost. That is capacity in each
|
||
|
home for twenty digital two-way HDTV channels at once at perhaps half the
|
||
|
cost of new telephone connections. Then, after a large consumer market
|
||
|
emerges for fiber optics, Hicks believes, Green's sophisticated computer
|
||
|
services will follow as a matter of course.
|
||
|
|
||
|
The consumer market, Hicks maintains, is the key to lowering the cost
|
||
|
of the components to a level where they can be widely used in office
|
||
|
networks as well. He cites the example of the compact disk laser diode.
|
||
|
Once lasers were large and complex devices, chilled with liquid nitrogen,
|
||
|
and costing thousands of dollars; now they are as small as a grain of salt,
|
||
|
cheap as a box of cereal, and more numerous than phonograph needles. An
|
||
|
executive at Hitachi told Hicks that Hitachi could work a similar
|
||
|
transformation on laser diodes and amplifiers for all optical networks.
|
||
|
"Just tell me what price you want to pay and I'll tell you how many you
|
||
|
have to buy."
|
||
|
|
||
|
The divergence of views between the IBM executive and the wildcat
|
||
|
inventor, however, is far less significant than their common vision of dark
|
||
|
fiber as the future of communications. By the power of ever cheaper
|
||
|
bandwidth, it will transform all industries of the coming information age
|
||
|
just as radically as the power of cheaper transistors transformed the
|
||
|
industries of the computer age.
|
||
|
|
||
|
For the telephone companies, the age of ever smarter terminals
|
||
|
mandates the emergence of ever dumber networks. This is a major strategic
|
||
|
challenge; it takes a smart man to build a dumb network. But the telcos
|
||
|
have the best laboratories and have already developed nearly all the
|
||
|
components of the fibersphere.
|
||
|
|
||
|
Telephone companies may complain of the large costs of the
|
||
|
transformation of their system, but they command capital budgets as large
|
||
|
as the total revenues of the cable industry. Telcos may recoil in horror
|
||
|
at the idea of dark fiber, but they command webs of the stuff ten times
|
||
|
larger than any other industry. Dumb and dark networks may not fit the
|
||
|
phone company self-image or advertising posture. But they promise larger
|
||
|
markets than the current phone company plan to choke off their future in
|
||
|
the labyrinthine nets of an "intelligent switching fabric" always behind
|
||
|
schedule and full of software bugs.
|
||
|
|
||
|
The telephone companies cannot expect to impose a uniform network
|
||
|
governed by universal protocols. The proliferation of digital protocols
|
||
|
and interfaces is an inevitable effect of the promethean creativity of the
|
||
|
computer industry. Green explains, "You cannot fix the protocol zoo. You
|
||
|
must use bandwidth to accommodate the zoo."
|
||
|
|
||
|
As Robert Pokress, a former switch designer at Bell Labs now head of
|
||
|
Unifi Corporation, points out, telephone switches (now 80 percent software)
|
||
|
are already too complex to keep pace with the efflorescence of relatively
|
||
|
simple computer technology on their periphery. While computers become ever
|
||
|
more lean and mean, turning to reduced instruction set processors, networks
|
||
|
need to adopt reduced instruction set architectures. The ultimate in dumb
|
||
|
and dark is the fibersphere now incubating in their magnificent
|
||
|
laboratories.
|
||
|
|
||
|
The entrepreneurial folk in the computer industry may view this
|
||
|
wrenching phone company adjustment with some satisfaction. But the fact is
|
||
|
that computer companies face a strategic reorientation as radical as the
|
||
|
telcos do. In a world where ever smarter terminals require ever dumber
|
||
|
communications, computer networks are as gorged and glutted with smarts as
|
||
|
phone company networks and even less capacious. The nation's most
|
||
|
brilliant nerds, commanding the 200 MIPS Silicon Graphics superstations or
|
||
|
Mac Quadra multimedia power plants, humbly kneel before the 50 kilobit
|
||
|
lines of the Internet and beseech the telcos to upgrade to 64 kilobit basic
|
||
|
ISDN.
|
||
|
|
||
|
Now addicted to the use of transistors to solve the problems of
|
||
|
limited bandwidth, the computer industry must use transistors to exploit
|
||
|
the opportunities of nearly unlimited bandwidth. When home-based machines
|
||
|
are optimized for manipulating high resolution digital video at high
|
||
|
speeds, they will necessarily command what are now called supercomputer
|
||
|
powers. This will mean that the dominant computer technology will emerge
|
||
|
first not in the office market but in the consumer market. The major
|
||
|
challenge for the computer industry is to change its focus from a few
|
||
|
hundred million offices already full of computer technology to a billion
|
||
|
living rooms now nearly devoid of it.
|
||
|
|
||
|
Cable companies possess the advantage of already owning dumb networks
|
||
|
based on the essentials of the all optical model of broadcast and select--
|
||
|
of customers seeking wavelengths or frequencies rather than switching
|
||
|
circuits. Cable companies already provide all the programs to all the
|
||
|
terminals and allow them to tune in to the desired messages. Uniquely in
|
||
|
the world, U.S. cable firms already offer a broadband pipe to ninety
|
||
|
percent of American homes. These coaxial cables, operating at one
|
||
|
gigahertz for several hundred feet, provide the basis for two way broadband
|
||
|
services today. But the cable industry cannot become a full service
|
||
|
supplier of telecommunications until it changes its self-image from a cheap
|
||
|
provider of one way entertainment services into a common carrier of two way
|
||
|
information. Above all, the cable industry cannot succeed in the digital
|
||
|
age if it continues to regard the personal computer as an alien and
|
||
|
irrelevant machine.
|
||
|
|
||
|
Analogous to the integrated circuit in its economic power, the all
|
||
|
optical network is analogous to the massively parallel computer in its
|
||
|
technical paradigm. In the late 1980s in computers, the effort to make one
|
||
|
processor function ever faster on a serial stream of data reached a point
|
||
|
of diminishing returns. Superpipelining and superscalar gains hit their
|
||
|
limits. Despite experiments with Josephson Junctions, high electron
|
||
|
mobility, and cryogenics, usable transistors simply could not made to
|
||
|
switch much faster than a few gigahertz.
|
||
|
|
||
|
Computer architects responded by creating machines with multiple
|
||
|
processors operating in parallel on multiple streams of data. While each
|
||
|
processor worked more slowly than the fastest serial processors, thousands
|
||
|
of slow processors in parallel could far outperform the fastest serial
|
||
|
machines. Measured by cost effectiveness, the massively parallel machines
|
||
|
dwarfed the performance of conventional supercomputers.
|
||
|
|
||
|
The same pattern arose in communications and for many of the same
|
||
|
reasons. In the early 1990s the effort to increase the number of bits that
|
||
|
could be time division multiplexed down a fiber on a single frequency band
|
||
|
had reached a point of diminishing returns. Again the switching speed of
|
||
|
transistors was the show stopper. The architects of all optical networks
|
||
|
responded by creating systems which can use not one wavelength or frequency
|
||
|
but potentially thousands in parallel.
|
||
|
|
||
|
Again, the new systems could not outperform time division multiplexing
|
||
|
on one frequency. But all optical networks opened up a vast vista of some
|
||
|
75 thousand gigahertz of frequencies potentially usable for communications.
|
||
|
That immense potential of massively parallel frequencies left all methods
|
||
|
of putting more bits on a single set of frequencies look as promising as
|
||
|
launching computers into the chill of outer space in order to accelerate
|
||
|
their switching speeds.
|
||
|
|
||
|
Just as the law of the microcosm made all terminals smart,
|
||
|
distributing intelligence from the center to the edges of the network, so
|
||
|
the law of the telecosm creates a network dumb enough to accommodate the
|
||
|
incredible onrush of intelligence on its periphery. Indeed, with the one
|
||
|
chip supercomputer on the way, manufacturable for under a hundred dollars
|
||
|
toward the end of the decade, the law of the microcosm is still gaining
|
||
|
momentum. The fibersphere complements the promise of ubiquitous computer
|
||
|
power with equally ubiquitous communications.
|
||
|
|
||
|
What happens, however, when not only transistors but also wires are
|
||
|
nearly free? As Robert Lucky observes in his forward to Paul Green's book,
|
||
|
"Many of us have been conditioned to think that transmission is inherently
|
||
|
expensive; that we should use switching and processing wherever possible to
|
||
|
minimize transmission." This is the law of the microcosm. But as Lucky
|
||
|
speculates, "The limitless bandwidth of fiber optics changes these
|
||
|
assumptions. Perhaps we should transmit signals thousands of miles to
|
||
|
avoid even the simplest processing function." This is the law of the
|
||
|
telecosm: use bandwidth to simplify everything else.
|
||
|
|
||
|
Daniel Hillis of Thinking Machines Corporation offers a similar
|
||
|
vision, adding to Lucky's insight the further assertion that massively
|
||
|
parallel computer architectures are so efficient that they can overthrow
|
||
|
the personal computer revolution. Hillis envisages a powerplant computer
|
||
|
model, with huge Thinking Machines at the center tapped by millions of
|
||
|
relatively dumb terminals.
|
||
|
|
||
|
All these speculations assume that the Law of the Telecosm usurps the
|
||
|
Law of the Microcosm. But in fact the two concepts function in different
|
||
|
ways in different domains.
|
||
|
|
||
|
Electronic transistors use electrons to control, amplify, or switch
|
||
|
electrons. But photonics differ radically from electronics. Because
|
||
|
moving photons do not affect one another on contact, they cannot readily be
|
||
|
used to control, amplify, or switch each other. Compared to electrons,
|
||
|
moreover, photons are huge: infrared photons at 1550 or 1300 nanometers
|
||
|
are larger than a micron across. They resist the miniaturization of the
|
||
|
microcosm. For computing, photons are far inferior to electrons. With
|
||
|
single electron electronics now in view, electrons will keep their
|
||
|
advantage. For the foreseeable future, computers will be made with
|
||
|
electrons.
|
||
|
|
||
|
What are crippling flaws for photonic computing, however, are huge
|
||
|
assets for communicating. Because moving photons do not collide with each
|
||
|
other or respond to electronic charges, they are inherently a two way
|
||
|
medium. They are immune to lightning strikes, electromagnetic pulses, or
|
||
|
electrical power surges that destroy electronic equipment. Virtually
|
||
|
noiseless and massless pulses of radiation, they move as fast and silently
|
||
|
as light.
|
||
|
|
||
|
Listening to the technology, as Caltech prophet Carver Mead
|
||
|
recommends, one sees a natural division of labor between photonics and
|
||
|
electronics. Photonics will dominate communications and electronics will
|
||
|
dominate computing. The two technologies do not compete; they are
|
||
|
beautiful complements of each other.
|
||
|
|
||
|
The law of the microcosm makes distributed computers (smart terminals)
|
||
|
more efficient regardless of the cost of linking them together. The law of
|
||
|
the telecosm makes dumb and dark networks more efficient regardless of how
|
||
|
numerous and smart are the terminals. Working together, however, these two
|
||
|
laws of wires and switches impel ever more widely distributed information
|
||
|
systems.
|
||
|
|
||
|
It is the narrow bandwidth of current phone company connections that
|
||
|
explains the persistence of centralized computing in a world of distributed
|
||
|
machines. Narrowband connections require smart interfaces and complex
|
||
|
protocols and expensive data. Thus you get your online information from
|
||
|
only a few databases set up to accommodate queries over the phone lines.
|
||
|
You limit television broadcasting to a few local stations. Using the
|
||
|
relatively narrowband phone network or television system, it pays to
|
||
|
concentrate memory and processing at one point and tap into the hub from
|
||
|
thousands of remote locations.
|
||
|
|
||
|
Using a broadband fiber system, by contrast, it will pay to distribute
|
||
|
memory and services to all points on the network. Broadband links will
|
||
|
foster specialization. If the costs of communications are low, databases,
|
||
|
libraries, and information services can specialize and be readily reached
|
||
|
by customers from anywhere. On line services lose the economies of scale
|
||
|
that lead a firm such as Dialog to attempt to concentrate most of the
|
||
|
world's information in one set of giant archives.
|
||
|
|
||
|
By making bandwidth nearly free, the new integrated circuit of the
|
||
|
fibersphere will radically change the environment of all information
|
||
|
industries and technologies. In all eras, companies tend to prevail by
|
||
|
maximizing the use of the cheapest resources. In the age of the
|
||
|
fibersphere, they will use the huge intrinsic bandwidth of fiber, all 25
|
||
|
thousand gigahertz or more, to replace nearly all the hundreds of billions
|
||
|
of dollars worth of switches, bridges, routers, converters, codecs,
|
||
|
compressors, error correctors, and other devices, together with the
|
||
|
trillions of lines of software code, that pervade the intelligent switching
|
||
|
fabric of both telephone and computer networks.
|
||
|
|
||
|
The makers of all this equipment will resist mightily. But there is
|
||
|
no chance that the old regime can prevail by fighting cheap and simple
|
||
|
optics with costly and complex electronics and software.
|
||
|
|
||
|
The all optical network will triumph for the same reason that the
|
||
|
integrated circuit triumphed: it is incomparably cheaper than the
|
||
|
competition. Today, measured by the admittedly rough metric of MIPS per
|
||
|
dollar, a personal computer is more than one thousand times more cost
|
||
|
effective than a mainframe. Within 10 years, the all optical network will
|
||
|
be millions of times more cost effective than electronic networks. Just as
|
||
|
the electron rules in computers, the photon will rule the waves of
|
||
|
communication.
|
||
|
|
||
|
The all optical ideal will not immediately usurp other technologies.
|
||
|
Vacuum tubes reached their highest sales in the late 1970s. But just as
|
||
|
the IC inexorably exerted its influence on all industries, the all optical
|
||
|
technology will impart constant pressure on all other communications
|
||
|
systems. Every competing system will have to adapt to its cost structure.
|
||
|
In the end, almost all electronic communications will go through the
|
||
|
wringer and emerge in glass.
|
||
|
|
||
|
This is the real portent of the dark fiber case wending its way
|
||
|
through the courts. The future of the information age depends on the rise
|
||
|
of dumb and dark networks to accommodate the onrush of ever smarter
|
||
|
electronics. Ultimately at stake is nothing less than the future of the
|
||
|
computer and communications infrastructure of the U.S. economy, its
|
||
|
competitiveness in world markets, and the consummation of the age of
|
||
|
information. Although the phone companies do not want to believe it, their
|
||
|
future will be dark.
|
||
|
|
||
|
#####
|
||
|
---
|
||
|
~ 1st 1.10b #1477 ~
|
||
|
--
|
||
|
Channel 1 (R) Cambridge, MA
|
||
|
|