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Switching and Transmission

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INVENTING THE INTERNET AGAIN
By
George Gilder
 
 
FOR THE FIRST TIME IN HIS LIFE as an engineer, Paul Baran was "scared stiff." That can happen to people who stumble too close to the abyss of 20th-century history and look over the edge. Born in 1926 in a house in a corner of Poland that had been claimed by three different nations during his parents' tenure, brought to America by his family at the age of 2, Baran was a child of European tempests.
 
But now, in the heady Southern California of the 1950s, the young Hughes Aircraft engineer found himself working in an American crucible. He was a design engineer for the Minuteman missile control system. Unlike the liquid-fueled Titans of the previous era, which required hours of preparation before they could fly, Minuteman could be instantly rocketed into the sky. To the Pentagon this seemed safer. The solid-fueled rockets would not be vulnerable for hours on the ground awaiting fueling. But Baran and his colleagues knew that this would be the most deadly and dangerous military system ever built. One accident and a cloud of missiles was on its way.
 
Appreciating the risks in the proposed design, Hughes summoned Warren McCullough from MIT as a consultant on human behavior. An expert on command and control-and a psychiatrist and brain surgeon to boot-McCullough explained the emerging facts of life. Throughout history, he told the Hughes engineers, the real command of the battle migrated to the men closest to the enemy. The man in the crow's nest, not the officers on the ship's bridge, was in de facto control. What he saw and reported determined the captain's orders. Regardless of nominal chains of command, the real governance of history moved to individual people on the front lines, often frightened or panicked at the time. But in the nuclear age, no such single person, necessarily fallible, could ever be trusted. Analyzing the technical problems of creating a command- and-control system for Minuteman, Paul Baran found himself abruptly in the crow's nest, stricken by historic terror-"scared stiff," as he recalls. It was clear to him that the problem was systemic; it could not be solved by tweaking the command-and-control schemes then being proposed at Hughes.
 
To explore the problem more broadly, Baran in 1959 left Hughes for RAND, the not-for-profit (the name stands for "R&D") set up after World War II to harbor the systems analysis skills developed during the war. At RAND the formidable strategist Albert Wohlstetter was demonstrating that in a matter of minutes Soviet short-range missiles could take out all U.S. foreign strategic air command bases encircling the Soviet Union. Then the Soviets could say stick 'em up-demanding surrender on the basis of the vulnerability of remaining U.S. missiles to superior Soviet forces. In many vivid papers and speeches, Wohlstetter relentlessly presented his argument that U.S. forces faced a "missile gap." The famed Alsop brothers, leading columnists of the day (Stewart was the father of the computer writer), echoed the Wohlstetter claims. John Kennedy listened and made the gap a theme of his 1960 presidential campaign.
 
Wohlstetter and his colleagues urged that the Pentagon redeploy its strategic forces to the United States and endow them with a second-strike capability-that is, to withstand a first strike and retaliate in kind. Greatly reducing the temptation to go first, this posture would escape the dangerous hair-trigger tenterhooks of the early cold war.
 
A viable second-strike capability, however, assumed that the command, control, and communications systems would remain intact. It was here that Baran fretted. He saw that one nuclear explosion at high altitude would affect the ionosphere for many hours and thus wipe out all long-range, high-frequency radio communications. In addition, one strike at the centralized switching nodes of AT&T would destroy the rest of the control network. The missile system might endure, but it would be deaf and blind.
 
Plunging deeper into history than Kennedy had, Baran resolved to design a communications system that could survive a nuclear attack and save the second-strike deterrent. He took inspiration from another idea of MIT's McCullough-a parallel computer system with adaptive redundancy. Like the human brain, such a system could reconfigure itself to work even after portions were destroyed. But using the noise-prone analog circuits of the time, it was impossible to build the necessary switches. Baran concluded that all the traffic would have to be digital. Moreover, the digital traffic would have to be broken into short message blocks now called "packets," each containing its own routing information, like a DNA molecule, and able to replicate itself correctly whenever a transmission error occurred. With many additions and permutations, his original design is today termed the Internet, and it is shaping the emerging history of the 21st century.
 
THE INEXORABLE LOGIC OF DIGITAL COMMUNICATION
 
Baran, though, is not satisfied with his creation. Contemplating its vulnerability to terrorism and other attack, he feels pangs of fear that echo his alarm of 40 years before. As more and more of the critical systems of advanced industrial society migrate to the Net, they become susceptible to new forms of sabotage, espionage, hacking, and other mischief. Air traffic controls, train switches, banking transfers, commercial transactions, police investigations, personal information, defense plans, power line controllers, and myriad other crucial functions all can fall victim to cybernecine attack. If the Internet is to fulfill its promise as a new central nervous system for the global economy, its security and reliability problems will have to be addressed.
Paul Baran
"Paul Baran is presently Chairman of the Board of Com21, Inc. He is generally blamed for creating the concept of what is now called packet switching and detailing its unusual properties in a series of RAND Memoranda in the early 1960s. He also designed and built the first doorway gun detector, and later recommended its use by the FAA to reduce hijackings. While at RAND, he was the first computer scientist to testify before Congress on the coming issue of computer privacy." From http://www.acm.org (external link)
 
Seventy-one years old, still with his Ph.D. economist wife Evelyn (their son David is director of information technology at Twentieth Century Fox Home Entertainment), Baran remains in the crow's nest, buffeted by inklings and insights of historic threats and opportunities. In a sense, Baran's current projects merely fulfill the far-reaching logic of his original concept, elaborated at RAND between 1960 and 1962 and published under the title "On Distributed Communications" in 11 compendious volumes in 1964: a survivable "network of unmanned digital switches implementing a self-learning policy at each node, without need for a central and possibly vulnerable control point, so that overall traffic is effectively routed in a changing environment."
To fulfill this scheme, Baran specified all the critical functions of the Internet: packets with headers for addresses and fields for error detection and packet ordering. He described in detail the autonomous adaptive nodes found in Arpanet IMPs (interface message processors) designed by Bolt, Beranek & Newman (BBN).
 
Baran also included features only recently and selectively introduced, such as encryption, prioritization, quality of service, and roaming ("provisions to allow each user to 'carry his telephone number' with him"). He described a web of peer nodes each connected to three or more other nodes, and he offered the first of the distributed routing algorithms that have multiplied over time.
 
Unique to his vision was its grasp of the economics of a network that could handle "the expected exponential growth in the transmission of digital data." Declaring that "it would be possible to build extremely reliable communications networks out of low-cost unreliable links, even links so unreliable as to be unusable in present-type networks," he estimated that the price of the system would be some $60 million per year. That was some 20 to 30 times less than what was being paid by the Department of Defense for their leased communications systems without any of these features. It was two orders of magnitude cheaper than new analog national systems being proposed at the time by each of the three military services.
 
Thus Baran not only conceived the essential technical features of the Internet, he also prophesied the cliff of costs over which digital technology would take the networking industry. By imagining the compounding effects of Moore's law three years before Moore's own famous prophecy, Baran stressed the key economic drivers that impelled the prevalence of the Web as the universal Net.
 
The system of communications that Baran attacked in the early 1960s at RAND was the imperial establishment of AT&T. As Baran explains, "While AT&T did have digital transmission under examination, it was in the context of fitting directly into the plant by replacing existing units on a one-for-one basis. A digital repeater unit would replace an analog loading coil. A digital multiplexer would replace an analog channel bank-always a one-for-one conceptual replacement, never a drastic change of basic architecture. I think that AT&T's views on digital networks were most honestly summarized by AT&T's Joern Ostermann after an exasperating session with me: 'First, it can't possibly work, and if it did, damned if we are going to allow the creation of a competitor to ourselves.'"
 
In 1972 the company sealed its fate by turning down an opportunity to buy the entire Arpanet. As Larry Roberts explained in {Where Wizards Stay Up Late}, "They finally concluded that the packet technology was incompatible with the AT&T network." So it was and so it still is. The existing phone system remains the chief obstacle to the final triumph of the Net. But the logic of digital communications is inexorable. It will displace all the existing establishments of television and telephony.
 
WASTED FOREVER...LIKE WATER OVER A DAM
 
These days Baran's vision, however, goes far beyond wireline communications. Baran takes the Internet model and extends it boldly to wireless communications. On June 23, 1995, on the occasion of the Marconi Centennial, marking the 100th anniversary of the invention of the radio, Baran gave a momentous keynote speech in Bologna, Italy. In it he demanded a radical reconception of wireless networks.
 
"The first 100 years of radio," he declared, were marked by a perpetual "scarcity of spectrum.... One of the very first questions asked of young Marconi about his nascent technology was whether it would ever be possible to operate more than one transmitter at a time. Marconi's key British patent #7,777 taught the use of resonant tuning to permit multiple transmitters.... [Yet] even today, with over 30,000 times more spectrum at our disposal than in Marconi's day, entrepreneurs wishing to implement new services encounter the same perpetual shortage of frequencies."
 
Focusing on the most desired bands between 300 and 3,000 megahertz (UHF), Baran asserted that when you "tune a spectrum analyzer across a band of UHF frequencies,:" you discover that "much of the radio band is empty much of the time. This unused spectrum might be available for transmission if we could take measurements and know exactly when and where to send the signal."
 
As an example, he cited "the many millions of cordless telephones, burglar alarms, wireless house controllers, and other appliances now operating within a minuscule portion of the spectrum and with limited interference to one another. These early units are very low power {dumb devices} compared to equipment being developed that can change its frequencies and minimize radiated power to better avoid interference to itself and to others.
 
"In part," he declared, "the frequency shortage is caused by thinking solely in terms of dumb transmitters and dumb receivers. With today's smart electronics, even occupied frequencies could potentially be used."
 
The chief reason for the apparent shortage of spectrum, he concluded, is regulation of it. Echoing his earlier critique of wireline communications, he declared that "the present regulatory mentality tends to think in terms of a centralized control structure, altogether too reminiscent of the old Soviet economy. As we know today, that particular form of centralized system... ultimately broke down. Emphasis with that structure was on limiting distribution rather than on maximizing the creation of goods and services. Some say that this old highly centralized model of economic control remains alive and well today-not in Moscow but within our own radio regulatory agencies."
 
The heart of the problem is the concept of spectrum as public property -- as scarce real estate or a precious natural resource. Spectrum is nothing of the kind. It has been created by a series of brilliant technical innovations, beginning with Marconi and continuing in a steady stream of high technology oscillators and digital signal processors: from magnetrons and kystrons to varactor multipliers and surface acoustical wave devices, from gallium arsenide and indium phosphide heterojunctions to voltage-controlled oscillators and Gunn or IMPATT diodes. Spectrum is chiefly a product of inventors and entrepreneurs. Americans will rue the day when foreign governments and international organizations begin auctioning and taxing, marshaling and mandating the use of these mostly American technologies.
 
The real estate model applies chiefly to broadcasters and others using analog modulation schemes in which all interference shows up in the signal. A television signal requires some 50 decibels of signal to noise power, or 100,000-to-1. By contrast, error-corrected digital signals can offer virtually perfect communications at a signal-to- noise ratio well below 10 decibels, or 10,000 times less. Moreover, new digital systems can divide and subdivide the spectrum space into cells and differentiate calls by spread- spectrum codes or even isolate particular connections in space by space-division-multiple-access-devices that function as "virtual wires" allocating all of the spectrum to each call.
 
Baran pointed out that "any transmission capacity not used is wasted forever, like water over the dam. And there has been water pouring here for many, many years, even during an endless spectrum drought.:" Although Baran urged as an ideal the transfer of the 480 megahertz of spectrum currently occupied by analog broadcasters to fiber optics and cable coax, he said, "We don't have to wait [for this ideal solution]....The existing spectrum can be more efficiently used by resorting to smart receivers and transmitters."
 
SMART RADIO IS A BRAIN BEHIND THE ANTENNA
 
To conceive of Baran's model of wireless, begin by thinking of the human eye and comparing it to a radio. Like a radio, the eye is essentially a device for converting photons into electrons, pulses of electromagnetic energy into electrical currents. Geared for visible light rather than radio frequency signals, the eye is a receiving antenna. As radio technology moves up through the microwaves toward the infrared realm-with infrared wireless links from Canon now reaching 155 megabits per second-many of the differences are dissolving.
 
Yet, in the crucial index of performance, the radio is drastically inferior to the eye. While most radios can receive signals across a span of frequencies ranging from the kilohertz to the megahertz, from thousands to a few million cycles a second, the eye can grasp signals with a total bandwidth of more than 350 trillion hertz (terahertz). That is the span of visible light, from 400 terahertz to 750 terahertz, red to purple.
 
How is it that your eyes command 350 terahertz of bandwidth and your FM radio around 20 megahertz, 17 million times less? It is not chiefly the special powers of the retina and other optical faculties. Radio antennas can collect an even larger span of frequencies. The difference is mostly behind the receiver. Backing up the eyes is the processing power of some 10 billion neurons and trillions of synapses. Backing up the radio antenna is a lot of fixed- analog hardware. Eyes are smart and aerobatic while the radio is dumb and blind.
 
In Baran's vision, the future of wireless is the replacement of current dumb radios by smart digital radios that resemble eyes. Coupling radio technology with computer technology, the antenna can acquire a brain. Smart radios can eventually process gigahertz of spectrum (billions of cycles a second). They can sort out the frequency channels much as eyes sort out arrays of color, and pin down codes and sources of radiation much as the eyes descry different sources, shapes, and patterns of light. For example, a smart radio could process phone calls, videos, teleconferences, geopositioning codes, speed-trap lasers, and emergency SOS's.
 
The result will be a transformation of the nature of the spectrum. The current real estate model will give way to a new view. Rights to spectrum will roughly resemble drivers' licenses for use on the highways. Today you use your 350-terahertz eyes to survey the highway in front of you and avoid other traffic. As long as you do not collide with other users, pollute the air, or go too fast (use excessive power), you can drive anywhere you want. As radios are computerized, they will be able to "see" the radio frequency spectrum as your eyes see the roads. Smart radios will be licensed to drive in open spaces in the air as long as they don't collide with other radios, overpower them, or pollute the airwaves.
 
As Baran argues, the fulfillment of this dream is at hand. It is the broadband digital radio or software radio. Essentially, the radios used in cellular or PCS (personal communications services) phones will be able to differentiate among frequencies; they will be able to tell which direction a signal is coming from and isolate it in space; they will be able to identify the language of codes and protocols and waveforms that it is using and download software translators. No longer caught in a dedicated set of channels, time slots, protocols, data types, and access standards, radios will be smart and agile rather than dumb and fixed frequency.
 
MOORE'S LAW WILL LEAPFROG TODAY'S LIMITS
 
This will not happen tomorrow. But like any technological vista, it illuminates the future. It opens the way to a new wireless paradigm, fully in place shortly after the turn of the century, that will mandate an entirely new model of wireless regulation and a new method for judging the evolution of companies and their prospects. In general, the companies on the path to broadband digital radios-the smart radio-will prevail over companies that hook their futures to hardwired machines linked to narrow spans of frequencies. Moore's law, the doubling of computer power every 18 months or so, is enabling the creation of broadband cellular radios in which most of the processing occurs in digital form.
continues on page 2 --->
From http://www.gildertech.com/public/telecosm_series/inventing.html (link now dead) The following article, INVENTING THE INTERNET AGAIN, was first published in Forbes, June 2, 1997. It is a portion of George Gilder's book, Telecosm, which waspublished in 1997 by Simon & Schuster, as a sequel to Microcosm, published in 1989 and Life After Television published by Norton in 1992. Reposted by permission. 
privateline.com logo http://www.privateline.com: West Sacramento, California, USA. A Tom Farley production

 

 

 
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