The basic idea of the NII is to provide information channels over which information services can be provided. Just as the highway system provides for traffic flow from place-to-place and the American Automobile Association (AAA) provides routing from point-to-point for interested drivers, the NII has a traffic flow and routing function. Like the highway system, the NII will have limits on how much traffic can go how far how fast. Like the highway system, when too many things go to the same place at the same time, there will be delays. Like the highway system, parts of the NII will break down from time to time, and the result will be inconvenience and reduced service capacity over certain routes.
The roads on the highway system have an analog on the NII called information channels, or simply channels. Just as roads have maximum flow limits, channels have channel capacities. Just as roads have intersections where cars can go one way or another, the NII has switching systems which route information from one channel to another. Just as roads have stoplights where cars line up, the NII has buffers where information queues up.
The history that led to the NII of today started with the telegraphic systems of the mid-nineteenth century. By the end of the nineteenth century, there were under 100 electrical paths for getting information across the United States and the signaling rate was limited by human capabilities to about five signals per second per line. The total U.S. signal capacity was only a few hundred signals per second.
Early telephone systems created in the first half of the twentieth century allowed people to call the operator and request a connection to another telephone. Since the number of wires was small, party lines, where many people shared a single telephone line, were common. You would pick up the telephone, and if the line wasn't busy, you could turn a crank that would put enough voltage on the line to sound a buzzer and light a light at the operator's station. The operator would plug a headset into your wire, ask if they could help, and you would tell the operator that you wanted to talk to Bill over at Tyson's Corners. The operator would try to hook a wire into Tyson's Corners, and ask the operator there to hook you up to Bill's line. If that line was available, that operator would hook the line up and signal that a call was coming in for Bill by ringing an appropriate number of rings in the right pattern. If Bill were in, he might pick up the phone, and the operators would tell each party to hold on while they plugged the wires in to connect you to Bill. You would talk till you were done, and then hang up. This would turn off the lights on the operator's console, and they would pull out the wires. This early telephone system allowed thousands of connections across the United States, each running at 4,000 signals per second of channel bandwidth. The total channel bandwidth across the US was now up to several million signals per second. This is almost as much bandwidth as the computer network in my office provides.
The next great innovation was the introduction of broadcast radio stations throughout the United States. With the introduction of radio, a full voice channel was simultaneously broadcast to hundreds of thousands of potential listeners. With this capability, a small number of people could send audio information to a large number of people. The channel bandwidth of only a few thousand signals per second had an effective information rate far exceeding newspapers and, even more importantly, the listener could get the information quickly without having to read it. This brought large amounts of information to many illiterate people.
Soon after broadcast radio came on the scene, dial telephones appeared. In this case, automation was used to replace the human operator in local calls. This early circuit-switching technology reduced the labor required for the telephone system, made calls more efficient for everyone concerned, and brought down the price of local telephone calls. Long distance still needed an operator. The increased switching speed increased the number of simultaneous calls, which increased bandwidth again. By this time the total number of signals per second available in the United States was on the order of one billion.
Television came next. Many thought that this new technology would make radio obsolete and revolutionize education for the masses. Neither has come true yet, but the effective bandwidth for television and the presence of pictures dramatically increased the requirement for high quality signaling, reception, and programming. Problems arose with measuring listener response and getting advertisers to pay for time, and these problems remain to a certain extent even today. Three nationwide affiliations were formed to compete for the market and these television networks dominated broadcast television until the 1980s when cable television took hold. Their larger market gave them more watchers which meant more advertising money and allowed them to create more expensive and better looking programs. This, in turn, made competition more difficult and created a sort of a triopoly (i.e., a three party monopoly - also the name of a board game).
Direct-dial long distance soon became available and this advancement in switching systems again changed the economics of telephones. International calls still needed operators, but the number of international calls compared to cross-country calls is relatively small. Automated switching systems were now getting to the limit of the complexity feasible for mechanical systems and repair costs were increasing substantially while reliability became an increasing concern.
Soon, electronic switching systems became a vital advancement to the telephone company and the effort to link electronic switching systems began in earnest. To send the digital switching information needed over analog wires, the modulator/demodulator (i.e., modem) was invented. As a general purpose tool for linking digital systems over analog wires, the modem became a core technology for linking computers, which were starting to come into widespread use. By this time, the total communications bandwidth in the United States was about $10^$ signals per second.
With the introduction of the integrated circuit, and the subsequent introduction of microprocessors and single board computers, the number of computers increased dramatically. Soon, there were millions of personal computers, and modems became increasingly important in linking distant computing sites together over telephone circuits.
Satellites began to be used for communication in the early 1960s. At first, relatively low bandwidth retransmitters were put into orbit and only a select few military installations had the knowledge and ability to use them, but soon, high bandwidth commercial satellites became available. By the 1980s suitcase-sized satellite transmitters and receivers were available for use in the field, and by the Gulf War, CNN was broadcasting live video direct from Bagdad during the initial bombings.
Cable television became available in major metropolitan areas and the effect on broadcast television was dramatic. Large local stations that had some of their own programming were now able to transmit over cable systems to other cities. In a very short time, a single station could become a nationwide mini-network and, if the programming was popular enough, it could make inroads against even the three major networks. As more of these niche channels became available over cable, the three major television networks began to decline in popularity and influence. Their death grip on television was broken.
Soon, there was enough money going into cable television to afford such wonderful capabilities as the Cable News Network , which was the first 24-hour-a-day cable news station, and Court TV, which broadcast courtroom proceedings directly into the common person's home. There is C-SPAN which broadcasts congressional hearings and other political events direct from the source. Astute viewers were now able to see the news first hand over live television feeds, watch the subsequent news stories, and make value judgments about how the media was interpreting the facts.
Today, the total communication bandwidth in the United States is on the order of $10^$ signals per second, and the vast majority of it is digital (1 or 0) signals.
As it exists today, the NII is a jumble of different networks. I will try to give a general idea of the different technologies currently in the mix.
As an overview, the NII consists of a set of communications technologies (e.g., satellite links) combined with commercial communications systems (e.g., telephone systems) to support protocols (e.g., NTSC video channels) which are used by information service providers (e.g., your local cable provider) to provide information services (e.g., The OJ Simpson case live from Los Angeles).
In the United States, free enterprise rules. Anyone who has the money to spend can launch a satellite, create a telephone system, implement a new protocol, provide access to services, provide programming, or in most cases, combine these together in any way they wish. There are some restrictions brought about by the federal licensing procedures relating to radio frequencies and satellite launches, but historically, anyone with enough money can buy these rights as long as that person doesn't monopolize the market.
The cost of implementing communications technologies on a large scale normally limits this part of the market to big players, but on a local level, ma and pa operations have started cable television systems for investments of a few thousand dollars, servicing as few as 10 or 20 customers.
When AT&T was broken up by the now famous Consent Decree, local phone companies covering only a few hundred people in a small town were fairly common. Today, many businesses have Private Branch eXchange (PBX) systems that turn their phone system into a local telephone company.
Novell, Banyon, 3-COM, LanTastic, and Little Big LAN are all commercial network protocol providers with their own communications protocols. Although standards such as TCP/IP are freely available and widely used, many companies opt for other protocols for the advantage of restricting access to their markets except by providers that pay them for the protocol development tools or because their protocol is a bit more efficient for some special application they want to implement.
Information service providers are springing up very rapidly today because the market for information services has not yet matured. For example, the number of computers on Internet has increased by a factor of 10 every two and a half years for quite some time. But in this case, it has to stop soon because at this rate, before the year 2000, every person in the United States will have their own computer on the Internet.
Communication technologies are roughly broken down into radiated energy waves (e.g., radio, television, microwave, and satellite transmission) and physically connected energy waves (e.g., shielded twisted pair wires, coaxial cables, fiber optics). The dominant infrastructure components today are copper wires, coaxial cables, fiber optic cables, microwave links, broadcast radio and television, and satellite links.
Commercial Communications Systems
Commercial communication systems currently include cable television systems (e.g., Warner Cable, TCI), long-haul telephone systems (e.g., AT&T, MCI, Sprint), regional and local telephone systems (e.g., New York Telephone, SouthEast Bell) and computer communications systems (i.e., Tymnet, NSFnet).
Packets and Protocols
Regardless of the physical means by which information is transmitted and received, the flow of information is organized and controlled by switching systems. Whereas historically, line switching or leased lines were used to make end-to-end connections, today, almost all computer communications and an increasing portion of the telephonic and video information is put into finite-sized packets which are switched in a store and forward network.
Store and forward networks transmit packets of information which are stored in switching computers along the route and forwarded to the next computer along the line until they reach their final destination. It is sort of like taking apart a 100-page report, numbering each page, and handing pages out to people in the front row of a classroom. The people then pass the pages around with the object of getting them to someone at the back of the room who reassembles them.
In order for these networks to operate, the intermediate computers must make routing decisions about which outgoing communications path to use to forward a packet to a particular destination when it came from a particular source. These decisions are based on the design of the network and information stored in the packets used to contain the information. The control of the network is carried out through a communication protocol, a formalized way in which the switching systems communicate with each other.
The same protocol can be used over almost any communication technology, so that the protocol creates a virtual communication environment that abstracts the physical nature of the media. The protocol is typically divided into a set of layers, each forming a packet which contains information at other protocol layers. By using the packet and protocol system as a virtual infrastructure, applications are implemented to provide user services. This is the so-called application layer of a protocol.
This was discussed in some detail in the introduction to the book.
Information is rapidly becoming a commodity. Information is already sold by the bit without regard to content or value. For example, for $29 or so, you can buy several thousand software packages on a CD-ROM, including spread sheets, databases, and all manner of other packages that high-priced vendors sell for hundreds of dollars per program. It's hard to tell where the real value lies without spending a lot of time and effort in analyzing the differences between products. Consumer reports may be good for looking at which car to buy, but there are only a few hundred choices of cars on the market today, while there are tens of thousands of software packages and information services, and Consumer Reports doesn't have a clue about where the value lies.
Good information is still expensive, and it is likely to remain expensive for some time to come, but the public as a whole is poor at differentiating good information from poor information, and very often chooses based on price and marketing rather than content and quality.
It is increasingly the meta-information (information about information) that has more value, and soon, the meta-meta-information (information about the meta-information) may become the real value. Round and round it goes, and where it stops, nobody knows.
The race is on to wire every home and office in the United States with fiber optic cables, to connect them to packet switching systems capable of handling the traffic, and to connect services of all sorts to this network. But the race is also on to regulate the NII and to find ways of attacking and defending it.
Current plans for the cable system are for regional wide-area networks (RWANs) that go between cities in a region of the continent with a capacity of 3 billion bits per second and are capable of supporting up to 50 cities, and national wide area networks (NWANs) that serve an entire continent and have a capacity of 10 billion bits per second or more. Current plans for telephone companies include wiring far more fiber optic connections between central offices (COs) and implementing digital compression to allow moderate quality video phones, integrated computer and communications services, and many other functions.
The next advancement may be implementing fiber optic switching systems that have similar switching capabilities to current telephone switches, but which switch optical fiber channels that have channel capacities of a trillion ($10^$) bits per second, and are multiplexed into a million simultaneous channels. One of these sorts of connections could serve a thousand households with a thousand channels each, and would last well into the future without substantial enhancements. To give you an idea of how much information could be moved with such a system, just one hundred of these fibers channels could carry as many bits per second as all of the personal computers in the world combined can now generate.
In fact, it is hard to comprehend how an individual household could use a thousand television channels worth of information. If 10 family members were each engaged in a 10 person conference call, this would only use 200 channels.
SouthEast Bell seems to believe in the fiber optic concept and they are now in the process of rewiring all homes receiving their service with fiber. Some of their competitors, on the other hand, take the position that fiber optic cables will never go to every home. [Reality]