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Addendum: (continued)

How the Internet Works

"Cyberspace. A consensual hallucination experienced daily
by billions of legitimate operators, in every nation, by children
being taught mathematical concepts. . . . A graphical representation
of data abstracted from the banks of every computer in the human system.
Unthinkable complexity."

William Gibson
Neuromancer (1984)

     We will begin our trip through cyberspace with a high-level (i.e., not deeply technical) view of the Internet, the wonderful communications medium that is catapulting so many imaginations into a new realm of pure thought. By the way, you don't necessarily need a computer to journey into cyberspace because, as is explained in this book's opening chapter, your mind is where cyberspace actually exists.

     As we travel from place to place on this mental journey, I recommend that you picture connections between the places we visit by stringing thin, imaginary fibers of light between them. Just like the old woodsmen who made crude diagrams of the trails they cut through a forest, it is helpful to build a mental map so we don't get lost. Imagining these fiber trails will make our trip more manageable.

E-mail

     Let's begin our journey through cyberspace by traveling from your home to our first stop, your cyber-neighborhood's electronic post office. Using your mind's eye, connect one end of a clear plastic fiber, or fishing line, to your house and then reel it out behind you as we travel through cyberspace to what is technically referred to as your e-mail server. (In case you are wondering, in the physical world your home computer is connected to your e-mail server through telephone lines that connect you with your Internet Service Provider, or ISP. Your e-mail server is often located in the ISP office.) You can think of this e-mail server, which is simply a special purpose computer, as your neighborhood post office in cyberspace. Picture your e-mail server as an actual post office building and attach the other end of your plastic fiber to its side. Now imagine that fiber as being filled with a pulsating light, which represents the "ones" and "zeros" of computerspeak. The ever changing patterns of this pulsating light are what carry the actual information flowing into and out of your personal mailbox.

     Simple, isn't it? It might surprise you to learn how close this image is to the physical reality of the Internet.

     You may also be surprised to see how alike cyberspace and our world of consensual reality actually are. Things just happen faster in cyberspace, almost as fast as the speed of light in many cases.

     Now bring to mind all of the people with whom you would like to be in contact-people like your friends, co-workers, former neighbors, relatives, celebrities, and so on. Then picture a thin, lighted fiber running from your e-mail post office to each of their neighborhood e-mail post offices. In your mind, connect a lighted fiber from each of these post offices to the homes and places of business where the people you want to contact will be reading their electronic mail. Done? Congratulations, you have just begun to construct your own working image of cyberspace.

     What cyberspace looks like in your mind's eye isn't important. What is important are the lighted fibers connecting these imaginary edifices, for it is these high speed information "pipes" that really set cyberspace apart from physical spacelight speed interconnections filled with pulsating information. After all, information and connections are what the Internet is really about.

     Perhaps the most important use of the Internet today is also its most commonly used application. I am talking about electronic mail, e-mail, which wins the prize as the killer application of the formative years of the Internet. Even after the advent of the World Wide Web and the introduction of multimedia, e-mail created the most traffic on the Internet. As audio and video technologies become more widely used on the Net, however, the raw number of bits being transmitted for e-mail purposes will lose their dominance, but we still may have a few more years before e-mail loses its title as king of the Internet applications.

     The first few e-mail messages one sends are usually to friends and family, but before long whole new vistas of like-minded spirits come into sight. Then the real power of e-mail can be appreciated. Two people who have never met in person can, nonetheless, become intimate friends through electronic mail. In fact, it may be the lack of face-to-face contact that is responsible for some of these new relationships blossoming into intimate friendships. Without having to process all of the data that is involved in judging someone's personal appearance and voice, we make a direct connection with the thoughts in that other person's mind. Think about this for a minute; with e-mail you can establish a direct channel of communication with another person's mind. So many possibilities begin to unfold.

     There are some pitfalls with electronic mail. For example, we have all read or seen reports in the popular media about the romances of men or women who get fooled by creative teenagers pretending to be someone older. Cases like those remind me of the famous cartoon from The New Yorker Magazine showing two dogs sitting in front of a computer where one dog says, "No one knows you're a dog on the Internet." Pause for a moment, however, and think about what is actually taking place in these cases of fictional e-mail identities. Forget for a moment about the age and gender of the individuals involved and think about the fact that what is happening is a sixty year old man or woman is engaged in a deep and meaningful conversation with a highly imaginative 15 year old boy or girl. There is a lot of intellectual activity taking place here, for e-mail exchanges like these create a temporary shared reality in cyberspace. In the case of online flirting, is that boy or girl lying or just being creative? As long as no one is physically, financially, or emotionally harmed, has any serious damage been done? While I am not promoting this type of behavior, it is nonetheless obvious that minds have been stretched, never again to return to their original dimensions. Emotions have been triggered. Human to human communications have taken place that otherwise never would have transpired. This can't be all bad. I believe it is important to keep in mind that there are many sides to these situations, and that not all unexpected results are negative.

     The next question is, "How does your electronic letter get delivered to the proper post office after you click the SEND button?" Obviously, there is a lot of complex equipment involved, the most important being the router. Without routers, there is no Internet.

Routers and Packets

     Whenever I think about what actually takes place when someone sends an e-mail message to a friend on the Internet, I am amazed that this technology even works once in a while, let alone millions of times a second. My highly technical friends may sneer at the following explanation of the inner-workings of the Internet because they are comfortable talking about TCP/IP stacks, and "improving performance by moving routing functions down to layer 3," and other seemingly arcane topics. But most people simply are not interested in that level of detail.

     One way to think of a router is to compare it with a heart. Both hearts and routers "pump" stuff, but the "stuff" routers pump is information, and that information is contained in packets. The concept of a packet is actually quite simple.

     The best analogy for a packet is that of a letter and an envelope. The letter contains the information, and the envelope, with the letter in it, is analogous to a packet. So a packet may be thought of as an electronic envelope, complete with an address, a return address, and some information inside. The thing about packets that may surprise you, however, is that your e-mail letter to a friend is broken into more than one packet. "Why," you might ask, "do we cut a letter into little pieces, send them one at a time, each in their own 'envelope,' and then force the recipient to tape them back together once they are received?" Good question.

     Let us continue with the metaphor of a postal letter to better understand how packets work. Assume for a moment that the governments of the world agreed to a common price for all postage. Assume further that, in their infinite wisdom, they also agreed that for a letter with only one sheet of paper in the envelope they will charge fifty U.S. cents to mail it anywhere in the world, but if you put two sheets of paper in the envelope they will charge you two U.S. dollars. (Don't laugh, governments have passed regulations far more moronic than that.)

     Now, how would you send a letter under those conditions if it contained two pages? The most economical way would be to place each page in its own envelope, purchase two fifty-cent stamps, and save a dollar in the process. Economics is also the reason your e-mail message is broken into smaller sections, or packets. It is just more efficient to send information in smaller, and more uniform-sized, packets.

     When you click the SEND button on your e-mail program, the first thing your computer does is to "cut" your message into smaller pieces. It then puts each piece in its own packet, adds the recipient's address, adds your return address, and adds some information that tells your friend's computer where to place each piece in relation to the other pieces that are coming in separate packets. These packets are then sent from your computer to the e-mail server in your office. Next, the packets proceed from your ISP router (which we will discuss in a moment) and on through a series of other routers to your friend's e-mail server. Eventually, they reach your friend's computer, which then magically stitches all the packets back together into a single message. Why is it done this way? Because it is more efficient. It costs less in terms of router and computer processing time. If you would like more detailed information on this topic, just visit your favorite bookseller and browse through their Internet section, where you will find dozens of texts on the subject.

     I should add one additional comment about e-mail, however. As you begin exchanging messages with more and more people, you may notice that sometimes the messages you receive are not formatted very well. You may see paragraphs with strange line spacing, perhaps with just one or two words on a line followed by a long line of text which is in turn followed by blank lines, etc. Don't panic. What has happened is that your e-mail program, technically your e-mail client, and the e-mail client of the sender are slightly incompatible. So, your e-mail program makes an educated guess as to how the letter should be reconstructed after it is received. Often they guess incorrectly about page margins, etc. Don't let it put you off, for some of the e-mail you send to others may also have this problem. These incompatibilities can be corrected, of course, but it is easier to live with a little sloppy formatting rather than spend time correcting software bugs, which often are due to the pressures of a marketplace that forces software manufacturers into quality compromises.

     Now that you understand the concept of packets, let's return to routers for just a moment. As you now know, when you click the SEND button on your e-mail application, the first thing that happens, right inside your own computer, is that your message is broken down into small sections, and each section is placed in its own "envelope," or packet. After your computer has all of these packets ready, it sends them along to your e-mail server, which, in turn, forwards them to the router that connects your ISP to the Internet. When that router sees the TO address on your first packet it asks the question: "Is the recipient's e-mail server connected to me?" If the answer is "Yes," the packets are sent to your friend's e-mail server. If the answer is "No," your router asks the question, "Am I connected to the router that the recipient's e-mail server is connected to?" If the answer is "Yes," your packets are sent to that router. If the answer is "No," it asks itself the question, "Which router am I connected to that will get this packet closer to the router connected to the recipient's e-mail server?" After looking up the address of that next closest router, it sends your packets on their way to that router. The router in your ISP office continues this process until all of your packets are "off its desk."

     All of the routers between your ISP office and your friend's e-mail server, in turn, ask themselves the same questions until the first of the above questions is answered in the affirmative, and the packets are delivered to your friend's e-mail server. From there your friend will pick up her or his e-mail and reassemble the packets into the letter you wrote. It is all quite simple, actually. At least it appears simple until one considers the fact that the latest generation of routers can move millions of these little packets on to the proper router every second! (Within five years of the time this book is first published people will laugh at how slow today's routers are.)

     One question you may ask is, "How do these routers know what e-mail servers, computers, and other routers are connected to them?" The answer, while seemingly simple, hides one of the most complex, and rapidly changing, parts of the Internet. The key to traffic flow on the Internet is in its routing tables. Essentially, a routing table is a map that shows the best route to every destination on the Net.

     How is your mental image of the Internet coming along? Do you remember the picture of cyberspace you began by connecting your home to your local electronic post office with a light-filled fiber? To make that picture a little more accurate, place a router in front of every post office in cyberspace. Now envision your computer connected to your ISP router, which is in turn connected to your electronic post office. It is important to add the router to the picture because it is also your gateway to other routers, which, in turn, will take you to web sites, chat rooms, Inhabited Virtual Worlds, IVW, and all of the other interesting places to be found in cyberspace.

     By now you can visualize the computer in your home connected by a light-filled fiber optic cable to your Internet service provider's router. Visualize that router connected to other routers which, in turn, are connected to yet more routers, and on to yet others, until you at last connect to the computer in your friend's house without even a post office between you. In fact, the post offices just seem to hang off these routers. So, when you check your e-mail what you are actually doing is going through your local router, which acts like a traffic cop, and then stopping in at your local post office to check your mail box. As you now see, there really isn't true home delivery of mail on the Internet. You have to "travel" to your local electronic post office to pick it up!

     Now let's try a mental experiment. Imagine the series of routers between you and your friend as each being connected to several other routers that aren't directly in the path to your friend's house. Can you see the web-like structure that is unfolding? If you and a friend are connected to the Internet and want to communicate directly with each other in a chat room, under normal conditions your messages would be passed from Router A to Router B to Router C and on to your friend's computer. Now assume that the connection from Router B to Router C has been broken. What do you think happens? Router B simply sends its packets along a different path to Router C. This new path may be less direct, but a few broken links won't keep your packets from getting through.

     It is not only a broken link that causes a router to send some of your packets along a different path. Perhaps the next router along the shortest path is busy, and the packets are stacking up on its "desk." (The technical term for this "desk" is buffer, which is the source of the expression, "My buffer just overflowed," that programmers sometimes use when they can't absorb any more information at the moment.) An overly busy router simply tells its neighboring routers that it is running behind. The neighboring routers then take mercy on it and send their packets along an alternate path. In theory, but seldom in actual practice, each of your packets could take a unique path to your friend's house. While you might think that all of this routing and packetizing is terribly inefficient, and that it may cause big delays, actually it works extremely well. In fact, it works so well that tens of millions of e-mail messages are sent and delivered every day, and this number continues to rise exponentially!

     Here was the real surprise for me when I first learned how routers worked: The largest amount of time consumed in this entire process is usually at the sending and receiving machines. Your computer and your friend's computer are quite often the worst bottlenecks in transmitting information over the Internet, not the routers that connect them. The disassembling and assembling of these messages into and out of packets usually takes the most time in this process. By the way, web pages are sent in exactly the same manner as e-mail messages, they are broken into packets and sent through routers. One way to speed up your Web browsing experience, therefore, is to get a faster computer, rather than change to a different Internet service provider.

     During a conversation I once had with a man who spent his entire career designing routers and other black boxes that make up the Internet's infrastructure, I was taken aback when this highly respected scientist answered my question about the workings of a new multi-gigabit router by saying, "it's magic." In a sense, this was the only answer possible.

     The deeper one digs into the essence of these black boxes and learns the details of moving packets of information from Des Moines to Moscow, the more the process resembles magic. The point at which understanding bleeds into magic is different for each of us. For the Internet novice, just clicking on a hypertext link for the first time and watching a web page appear on the screen is often a magical experience. For the Internet engineer who spends her days working with complex routing algorithms, the magic may begin to shine through at the chip level; deep within the routers of which she appears to be the master. As Arthur C. Clarke's (1) third law of technology says, "Any sufficiently advanced technology is indistinguishable from magic."

     Of course, magic carries different meanings for each of us depending upon our cultural backgrounds. Personally, I don't like television programs that expose famous magical illusions. For me, a little magic makes life more interesting. So, you might wish to be careful about trying to gain too complete an understanding about the technical nature of the Internet if all you want to do is surf the Web and communicate with friends. In the final analysis, all of the technical descriptions in the world will not explain the phenomena we call "the Internet." I see nothing wrong with believing that one aspect of the spirit of the Internet is magical.

What is the Internet

     Now that you have a basic understanding of routers and packets, it is time to tackle the issue of just what is this thing we call the Internet. Given its importance and the amount of media coverage the Internet receives, it is sometimes hard to believe that the Internet is nothing more than a network of networks that are connected by routers and other such devices. Of course, the phrase "nothing more than" belies the fact that it is also the largest and most complex technological artifact ever created by humankind!

     What then, you ask, is a network? In the context of the Internet, the word "network" refers to a chain of interconnected computers. For example, many businesses today connect their computers to a Local Area Network, a LAN, to save the expense of buying individual printers for every employee. By use of a LAN, several computers can share common services such as file storage and printing services, which often require expensive equipment. All you really need to know about networks for the purposes of this book is that they are somewhat complicated combinations of wire, software, and black boxes that move information, usually in the form of packets, from one computer or peripheral device to another.

     In addition to Local Area Networks, which are usually confined to a single building or to a small group of geographically close buildings, there are also Metropolitan Area Networks, MANs, which cover relatively small geographical areas. Another common type of network is the Wide Area Network, or WAN, which generally covers a much larger area, such as a state or country.

     All of these types of networks, LAN, MAN, and WAN, operate independent of each other. Not all use the same protocols, and each has its own administrator and rules of operation. For a computer on one network to exchange information with a computer on a different network, a router must connect the two networks. (Actually, there are other connecting devices such as gateways and bridges involved in interconnecting networks, but a discussion of these devices is too technical to be included here and would add nothing to the discussion that follows.) Two networks connected to each other are called an "internet." (Note the lowercase "i.") While there are many of these smaller internets, often called "Intranets," the interconnection of all of them into a single, global network is the communications medium we call the Internet.

     Why, you may ask, would someone own a network and not connect it to the Internet? There could be many reasons for such a choice, but the most important ones are security and economics. Although it is difficult, and in some cases extremely difficult, for unauthorized persons to gain access to information they aren't entitled to see on a computer network, whenever computers are interconnected the possibility of unauthorized access exists. A good computer security expert will tell you that the only way to ensure that your data remains secure is to disconnect the computer from all networks, unplug it, and bury it in the back yard. What they are saying is that given enough time and computing power, any computer network can be hacked. (2) That, in addition to the fact that it costs money to connect a LAN to the Internet, is the primary reason some computer networks are not "on the Net."

     There you have it, at least at a basic level. Using your telephone line, you connect your home computer to the network that is operated by your Internet Service Provider, your ISP. This ISP network is then connected to other ISP networks and to the networks of information providers through routers. (See Figure A-4 on page 192 of the PDF or paperback edition.)

     This globally interconnected network of networks is what we call the Internet. It sounds simple, and from this elementary point of view it is. Only when one begins to dig deeper into the underlying technology do you begin to understand the "unthinkable complexity" of this global communications medium we are building.

     Fortunately, in order to use the Internet you don't need to know any more about its inner workings than you do about the ignition system on your automobile. All you really need to know is how to get it started and which roads to take. If you want to, you can leave everything else up to the technicians, scientists, and engineers who are building this infrastructure. The only semi-technical details you may want to check out are the "rules of the road" and who makes these rules.


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