
Inside The Internet
By: Peter Wealick
According to Computer Industry Almanac, there were more than 533 million Internet users in 2000. There were more than 149 million users in the North America and 126 million in Western Europe.
Most of the time, you couldnt care less about how the Internet works. As long as youre getting your email and you can find the latest baseball scores on the Web, youre happy.
Its those times when your Internet connection is broken in the middle of a three-hour file download or when the Web site you want to visit delivers an error message that you probably exclaim, "How does the Internet work, anyway?"
The Internet is actually an amazing collaboration of thousands of networks around the world, sharing information using a single protocol. In 30-plus years, the Internet has grown from a four-computer network to an estimated 533 million users or more. Yet the protocols developed in the Internets early stages continue to be used today.
Physical Components. Youll discover that exact data about the Internet, such as the number of users or the exact routing of cables, is impossible to find. Thats because no single entity owns or oversees the Internet, making it tough to track all of the components or count the users.
The components that make up the Internet are owned and shared by thousands of public and private entities. The supercomputers, or NAPs (Network Access Points), that serve as the major hubs of the Internet are owned by several companies, including MCI WorldCom and AT&T. The connections spread out from the NAPs to routers (Internet-dedicated computers that move Internet traffic) and regional networks through high-speed cables, called backbones. The NAPs are connected to each other by backbones. Spreading out from the regional networks are smaller networks, private networks, and ISPs (Internet service providers). Your Internet connection almost certainly will come through an ISP or through a private network at your company, governmental entity, or educational unit.
The components that make up the Internet come in a variety of forms. Some computers are dedicated to routing Internet traffic, while others share their resources between the Internet and private networks. Some cables that serve to connect remote offices for a single company also carry Internet traffic. The private companies that own the routers and Internet components have a working agreement stating theyll carry each others traffic to make the Internet work as smoothly as possible.
Cabling. Smaller networks and individual ISPs handle far less Internet traffic than the major routers or NAPs, and the cable connecting them is much smaller than the backbone cables. Several sizes of cables connect the various components of the Internet.
Smallest. These cables, normally used by individuals and small businesses to connect to the Internet, include common telephone lines. Speeds ranging from 14.4Kbps (kilobits per second) to 128Kbps are common.
Small. Outside of common telephone lines, individual users have several options for faster Internet connections, including cable television lines, satellite television connections, and digital telephone lines, such as DSL (Digital Subscriber Lines). Speeds usually range from 128Kbps to 8Mbps (megabits per second), or about 8 million bits per second.
Medium. Companies using ISPs to connect to the Internet tend to use cables dedicated to carrying Internet traffic to make the connection. Some of the cables in use are T1, T2, and frame relay. Speeds usually range from 512Kbps to 20Mbps.
Large. As the ISPs connect to the Internet, they need high-speed, dedicated cables to carry the traffic from all of their customers. Although some smaller ISPs use twisted-pair or coaxial cable to make this connection, others use optical fiber. Large companies that connect their networks directly to the Internet also may use these large cables, including T3, T3D, or OC1. Speeds usually range from 8Mbps to 135Mbps.
Largest. The cables used to create the Internet backbone, connecting the NAPs to routers and to each other, are the largest and fastest cables. Optical fiber is used for the largest cables, which include OC3, OC12, OC24, and OC256. Speeds usually range from 125Mbps to 13Gbps (gigabits per second), or about 13 billion bits per second.
TCP/IP. The key to downloading and sharing data across the Internet in a format that may be read and deciphered by almost any computer, no matter what OS (operating system) its running, is TCP/IP, or Transmission Control Protocol/Internet Protocol. TCP is the protocol used to break the data into packets, which are the largest blocks of data that can be sent across the Internet (less than 1,500 characters or 128KB). IP is the protocol used to send the data across the Internet to its final destination. TCP is then used again to reassemble the packets in the correct order. TCP also checks the packets for any errors that may have occurred during transmission.
The TCP and IP protocols work together to transmit data from one Internet destination to another, whether youre sending an email message to your mom or accessing the latest stock quotes from your Web broker. Other protocols may work inside the parameters of TCP/IP, depending on the type of Internet usage.
When one computer is told to send data across the Internet, TCP is applied to the data. TCP creates each packet, adding a header and a checksum (a calculated value transmitted with data to check for errors in the transmission) to each packet. The header specifies the order in which the packets must be reassembled; the checksum specifies the exact amount of data in the packet. This is used to check for errors.
Next, IP is applied to each packet, labeling each packet with its destination address. You can think of the IP process as placing each packet inside an envelope with the destination address printed on the outside.
The packets are then sent along the Internet network (a group of computers that are connected and can share data because theyre using the same protocol or OS). Because the Internet is the ultimate networkoften called a network of networksthe packets may encounter several different types of computers running several different OSes. TCP/IP is the common thread, though. Just as computers in a corporate network can communicate because theyre running the same OS, all computers on the Internet can communicate because they can all use TCP/IP.
As the packets travel along the Internet, they encounter routers. The routers read the IP address on each packet. If the packet is destined for the regional network or local network served by the router, it directs it to the final destination. Otherwise the router must send the packet along to the router closest to the packets final destination.
The router uses a router table to determine where to send the packets. A router table is a database stored in the router with information about which routers should handle certain addresses. Some routers, called static routers, always send the packets in the same direction. Other routers, called dynamic routers, can choose from several different routes, bypassing busy routers to move the packets more quickly. You can think of the static router as a commuter who always drives the same route to work, regardless of the rush-hour consequences. A dynamic router would be similar to a commuter who listens to radio reports on traffic congestion before choosing the best route to work.
During the busiest times of Internet usage, you probably notice some slowing in Web page loading or file downloading. One explanation is the routers are receiving requests to move packets faster than they can handle them, causing some packets to be lost. When a packet is lost, it must be re-sent, causing additional traffic and additional delays.
Once the packets arrive at their final destination, TCP is used to check each of them for errors, using the checksum. If any errors are detected, a request is made to have the packet re-sent. After all of the packets arrive; TCP is used to arrange them in the correct order, making them readable.
The Web. Without TCP/IP, transferring data between computers on the Internet would be nearly impossible, no matter what portion of the Internet you were using, including the Web.
The World Wide Web (often shortened to WWW or Web) is probably the portion of the Internet with which youre most familiar; the Web has become the commercial arm of the Internet. Whether you want to purchase a book, research a stock, the Web is probably where youll turn. The Webs ability to deliver a mixture of graphics, photos, audio clips, video clips, and text make it a powerful tool.
To use the Web, you must first make an Internet connection and open your Web browser (the software that lets you load and view documents from the Web). After you type the URL (uniform resource locator) of the Web page and press ENTER, a complex process takes place behind the scenes to load the Web page. The address is sent across the Internet using a combination of TCP/IP and HTTP (Hypertext Transfer Protocol), the protocol used by Web browsers and servers to communicate.
Each portion of the Web address is important to loading the proper page. The http: at the beginning of the address signifies the use of HTTP. The www signifies use of Web technology. The address.com or address.org portion signifies the exact Web server that contains the desired Web page. The portion of the address after the .com or .org specifies a particular page or directory on the server.
Web routers move the address along the Internet, steering it toward the correct server. Once the server receives the address, it sends the Web page and any accompanying graphics and text back across the Internet to the computer that made the request. The Web browser accepts all of the elements and assembles them in the correct order to be displayed.
Once the Web server completes your request, it moves on to another request; it doesnt keep a connection open for any additional requests from you. If you later make another request from the same Web server to load another page, the entire process begins again. However, subsequent pages may load more quickly because some of the elements of the page are already stored in the Web browsers cache memory on your computer.
Internet Information. The amount of data on the Internet is overwhelming to consider. But who creates this data? Here are some of the main groups that provide Internet data.
Commercial.
Companies see the Internet, and especially the Web, as a large money- making market where they can sell products. Some Web-based companies, such as Amazon .com, already have established themselves. Such Web storesand the Internet advertising that accompanies themshould continue to provide a large chunk of Internet data.Navigating The Internet. So how do you get to that recipe? Connecting to the Internet is easy using modern equipment. There are a variety of ways to access the Internet, and you dont even need to own a computer.
Modem. The most popular way for individuals to gain access to the Internet is through a computer modem connected to a telephone line. (A modem is a piece of hardware that translates computer data into signals that can be transmitted across telephone lines.) The modem dials your ISPs modem, making the connection. The ISPs computer serves as your gateway to the Internet, transferring your data requests to the proper server on the Internet.
To read Web data or to send and receive email, youll need Web browsing software.
LAN. Many companies let employees connect to the Internet through the companys LAN (local-area network). Larger companies often have an Internet server available that manages all active Internet connections along the network. Such companies usually use a dedicated cable to keep the Internet connection available at all times. As long as youre connected to the network and you have the right software, you can access the Internet through the LAN.
The Future. Considering the evolution of the Internet and the increase in traffic during the 1990s, the ability of the Internet to thrive using many of its original protocols is remarkable. The developers of the Internet may not have foreseen all of todays uses for the technology, but they did plan for most of them.
How long the Internet will continue to operate in its current form is impossible to predict. As Internet2 develops and as new protocols are created, theyll probably begin to filter down to the original Internet, expanding its ability to deliver data more efficiently and more quickly.
Until then, Internet users will have to suffer through the occasional irregularity or quirk. Now that you know the hoops the millions of packets must travel through before reaching your computer, you probably can forgive the occasional error message.
I hope that this information is helpful in your day-to-day operation of your computer. If you have any question Aboriginal Computer Solutions technical support can be reached either by email or telephone.
Peter Wealick is a citizen of the Sto:lo Nation, TZEACHTEN reserve located in Sardis B.C. and is the president of Aboriginal computer Solutions Ltd. He has a diploma of Technology in computer systems and has been in the technology industry for over twenty years.
Aboriginal Computer Solutions Ltd. is a technology company specializing in the supply of computer products, related services and solutions.
Aboriginal Computer Solutions Ltd.
Can be contacted at
Tel: 604-925-8106
Fax: 604-925-8156
Email: support@acsl.ca
Or visited us the web at
www.acsl.ca
Home | Archive | Subscription Rates | Advertising Rates
© 2000 Kahtou News - kahtou@dccnet.com