The Internet - When, Who, Why, What and Where

The modern Internet began life in 1969 as a group of large mainframe computers (located at various universities and research centers) tied together through a network of wire, microwave and satellites. This project was funded from the U.S. Governments Advanced Research Projects Agency or ARPA. Hence it was first known as the ARPANET.

The original aim was to create a network that would allow users at any one site to be able to communicate with users at any other site. The network was designed so it could continue to function even if parts of it were destroyed in the event of a military attack or other disaster. This net or web like design, wherein messages could be routed or rerouted in more than one direction or path across the network, made the system highly redundant and therefore survivable.

The Internet today is a cooperative, public, self- sustaining facility connecting hundreds of millions of personal computers and people worldwide. Physically, the Internet now uses a portion of the total resources of currently existing private telecommunication networks such as those used for telephone and Teletype communications. Technically, what distinguishes the Internet from standard voice type communications is its use of a set of data transmission and reception rules (called protocols) such as TCP/IP (Transmission Control Protocol/Internet Protocol). Two recent adaptations of Internet technology, the Intranet and the Extranet, also make use of the TCP/IP protocol.

Today the Internet provides several basic methods of moving information. These are electronic mail (e-mail), the world wide web (WWW), Internet relay chat (IRC) and Newsgroups.

A computer connected to the Internet can run Server and or Client software. Email programs and Web Browsers used on your home PC are known as Clients because they receive services (data) from sources called Servers (special software programs running on a remote machine whos job it is to serve up data to its clients). The term Server can also apply to a PC whose primary job is to store and render data. The term Daemon also means Server. In Greek mythology, Daemons were half human entities who passed messages between the God's.

The Internet uses a unique addressing system to find and communicate with other computers. This address is called a Universal Resource Locator or URL. A URL is a verbose grouping of words like www.cnn.com that seems to magically know where a request should be routed to on the network. In fact, the network really depends on numerical addresses called Internet Postal numbers or IP's. However, designers knew in the early days people would have an easier time remembering names rather than numbers. In point of fact, the network cannot really find anything with a URL until it is resolved into the actual IP it is paired with. IP's are 4 byte values (sets of numbers that can range from zero to 255) separated by periods. This is called a dot quad. Example, www.cnn.com resolves to 207.25.71.8 which is its actual address on the internet. Special Domain Name Servers (DNS) exist on the Internet for the purpose of matching verbose addresses to usable IP's.

A URL like "http://www.cnn.com/somedir/page.htm" consists of 3 parts: The Protocol (http,telnet,ftp etc), the Domain Name (cnn.com), and the location to the source or Path/File (/somedir/page.htm).

So you type in www.cnn.com and behind the scenes your computer contacts a DNS server to get the actual IP so a packet request from your PC can be properly addressed and routed along the net to its destination. Within seconds all you see is Cable News Networks web page appearing on your screen.

For many Internet users, electronic mail (e-mail) has practically replaced the Postal Service for short written transactions. Electronic mail is the most widely used application on the Net. You can also carry on live "conversations" with other computer users, using IRC (Internet Relay Chat). More recently, Internet telephony hardware and software allows real- time voice conversations.

Another often overlooked service on the Net today are the Newsgroups or NNTP Services. Some of you may have started your modem life by contacting BBS'es (or Bulletin Board Service's) in the late seventies and eighties. Each BBS had a "theme", "subject" or "topic" that it catered too. For instance if you were a Pilot, you likely dialed BBS'es involved in Aviation. The big limitation for most users was their toll free calling radius unless they did not mind paying long distance charges. When the Internet Technology boomed, BBS'es died on the vine. However the demand for gathering places of people of common interest did not. Thus evolved the Newsgroups which began life as a few dozen topics shared by mostly researchers and scientist. Today the individual topic groups in the system number over 80,000. Newsgroups allow the user to POST, REPLY TO and READ messages posted by others. Some groups are moderated and have strict rules and others are lax and loose. To access Newsgroups a client called a Newsreader is required. Many Browsers or E-Mail clients have a Newsreader built into them. But for the purist, a stand alone client like Forte's AGENT Newsreader is the only way to go.

The most widely used part of the Internet today is the World Wide Web (often abbreviated "WWW" or called "the Web"). Its outstanding feature is the use of hypertext links, a method of instant cross-referencing. What makes hypertext links unique is one second you may be reading a document on a computer at your local university and with the next link a document on a system in England. In most Web pages, certain words or phrases appear in text of a different color than the rest; often this text is also underlined. When you click one of these words or phrases, you will be transferred to the site or page that is relevant to this word or phrase. Sometimes there are buttons, images, or portions of images that are "click able." If you move the pointer over a spot on a Web site and the pointer changes into a hand, this indicates that you can click and be transferred to another site.

Using the Web, you have access to millions of pages of information. Web "surfing" is done with a Web browser, the most popular of which are Netscape Navigator and Microsoft Internet Explorer. The appearance of a particular Web PAGE may vary slightly depending on the browser you use. The language of the Web is HTML or Hyper Text Markup Language. HTML is a constantly evolving programming language. As such, not all Browsers are up to date. The latest versions of any particular Browser are always able to render the "bells and whistles" (animation, virtual reality, sound, music) much better than the earlier versions. It pays to stay current!

A request for a Web Page somewhere on the World Wide Web travels through a complicated labyrinth that is generally referred to as the "infrastructure" of the Net. It starts at you modem, goes through your phone system to your Internet Service Provider, then out on the Net over a grid of wire, microwave and satalite links until it arrives at the destination. This may be another Internet Service Provider who then routs it to a customer system or direct to another network.

Unless you are using a direct connection with a NIC (Network Interface Card) Your computer typically makes one phone connection vi a modem to an Internet Service Provider and activates a communication protocol between your PC and the Net called TCP/IP. The reason you can have several specialized Net Clients all running at the same time, but accessing completely different servers for different kinds of data, is because your connection protocol (tcp/ip) can divide into many different virtual connections (up to 256) each of which can communicate on up to 65,000 separate channels called Ports. Example, by international agreements, e-mail clients communicate on port 25 and 110, Telnet on 23, FTP on 21, the WWW on port 80.

Section Two: The Technical Details

After traveling through your phone line or other path and then through the telephone company central office (or your enterprise's proxy and firewall servers), your Web page request travels successively through:

Your Internet service provider (ISP) server The regional network your ISP is connected to If necessary, through one of the four major network access points (NAPs) in the U.S. Then through the national commercial Backbones.

And then once again through the NAP, regional network, and ISP at the other end. Sounds complicated? thats because it is!

The regional networks and many Internet service providers (ISPs) connect to several major commercial networks that provide the backbone or superlink that carries your Web requests and returned pages cross country or on to international destinations. (Most of the major Internet service providers are also national commercial backbone providers.)

The actual physical wiring is often leased by the networks from Regional Bell Operating Companies (RBOCs) or other telephone companies. The Internet networks interconnect the leased lines with their own routers and switchers. Routers share information with adjacent routers about the best routes to use. The agreements among ISPs and the backbone providers to interconnect and carry each other's traffic are called peering agreements.

The regional networks and tributaries of the major commercial networks intersect at four main network access points (NAPs) near New York, Washington, D.C., Chicago, and San Francisco.

Major companies that provide this collective backbone (they sometimes rent or share each other's lines) include:

AT&T Network Services
BBN Planet
Cable & Wireless USA
Sprintlink
UUNET, a part of MCI WorldCom

In general, the NAPs interconnect with each other and with major cities that feed into them with T-3 lines. Locations with less traffic are connected with T-1 lines. Cable & Wireless USA includes a large ATM network with OC-3 lines. Many regional ISPs interconnect directly with each other for regional connections that do not need to go through a NAP.

In addition to the commercial backbone, there is also a national scientific backbone called the "very high speed Backbone Network Service" (vBNS) that interconnects five supercomputer centers in the United States.

The T-carrier system, introduced by the Bell System in the U.S. in the 1960s, was the first successful system that supported digitized voice transmission. The transmission rate for a T1 is 1.544 Mbps. The T-1 line is in common use today in Internet service provider (ISP) connections to the Internet.

Another level, the T-3 line, providing 44.736 Mbps, is also commonly used by ISPs. Another commonly installed service is a fractional T-1 line, which is the rental of some portion of the 24 channels in a T-1 line, with the other channels going unused.

The T-carrier system is entirely digital, using pulse code modulation and time-division multiplexing. The system uses four wires and provides full-duplex capability (two wires for receiving and two for sending at the same time).

The T-1 digital stream consists of 24 64-Kbps channels that are multiplexed. (The standardized 64 Kbps channel is based on the bandwidth required for a voice conversation.) The four wires were originally a pair of twisted-pair copper wires, but can now also include coaxial cable, optical fiber, digital microwave, and other media. A number of variations on the number and use of channels are possible.

In the T-1 system, voice signals are sampled 8,000 times a second and each sample is digitized into an 8- bit word. With 24 channels being digitized at the same time, a 192-bit frame (24 channels each with an 8-bit word) is thus being transmitted 8,000 times a second. Each frame is separated from the next by a single bit, making a 193-bit block. The 192 bit frame multiplied by 8,000 and the additional 8,000 framing bits make up the T-1's 1.544 Mbps data rate. The signaling bits are the least significant bits per frame.

ATM (asynchronous transfer mode) is a dedicated- connection switching technology that organizes digital data into 53-byte cells or packets and transmits them over a medium using digital signal technology. Individually, a cell is processed asynchronously relative to other related cells and is queued before being multiplexed over the line.

Because ATM is designed to be easily implemented by hardware (rather than software), faster processing speeds are possible. The pre specified bit rates are either 155.520 Mbps or 622.080 Mpbs. IEEE Spectrum reports that speeds on ATM networks are expected to reach 10 Gbps.

The Synchronous Optical Network (SONET) includes a set of signal rate multiples for transmitting digital signals on optical fiber. The base rate (OC-1) is 51.84 Mbps. OC-2 runs at twice the base rate, OC-3 at three times the base rate, and so forth. Planned rates include OC-1, OC-3 (155.52 Mbps), OC-12 (622.08 Mpbs), and OC-48 (2.488 Gbps). ATM makes use of some of the Optical Carrier levels.

The vBNS (very high-speed Backbone Network Service) is a network that interconnects a number of supercomputer centers in the United States and is reserved for science applications requiring the massive computing that supercomputers can provide. Scientists at the supercomputer centers and other locations apply for time on the supercomputers and use of the vBNS by describing their projects to a committee that apportions computer time and vBNS resources. The vBNS and the supercomputer centers were initiated and are maintained by the National Science Foundation (NSF).

The vBNS began operation in April, 1995, as the successor to the NSFNet. The NSFNet itself succeeded DARPANET, the original Internet network. The vBNS is the scientific portion of the Internet that NSF continues to fund. The physical infrastructure for the original Internet is now owned and maintained by the national commercial backbone companies in the United States and worldwide.

Currently, MCI provides the backbone infrastructure for the vBNS under contract from the National Science Foundation. The backbone consists mainly of interconnected OC-3 lines (operating at 155 Mbps or higher). The vBNS provides connections to the four national network access points (NAPs). The vBNS infrastructure itself is not shared with commercial companies and ordinary users.

As part of the evolution toward a commercially self- sustained Internet, the National Science Foundation continues to operate the routing arbiter, a service that the NAPs and other routers use to route and reroute packets and optimize traffic flow on the Internet. The routing arbiter service is managed by Merit under a contract from the NSF that expires in July, 1999.

The vBNS has recently become part of the infrastructure of Internet2. A new NFS-funded initiative is developing an advanced network infrastructure referred to as the National Technology Grid.

Who Runs the Internet:

The Internet is a public collaboration. No one person, organization, or group of organizations owns it. It grew from a relatively small network of four computers used in research for the United States defense establishment into a public system comprised of hundreds of commercial telecommunication networks of all sizes, thousands of institutions, hundreds of thousands of businesses, and at least 30 million individual users. Who really runs it and keeps it going? You. In your roles as economic producer and consumer, as information user, as free-speech advocate and concerned parent, as a political participant in your own community and the world community, you have a real interest in seeing that the Internet serves you well. Fortunately, there are many ways to do this.

The Internet Society. The institutional "soul" of the Internet. You can join.

The Internet Architecture Board. Among other things, this Internet Society board oversees the IETF.

The Internet Engineering Task Force. This group, composed of working members from many corporations as well as interested and competent individuals, maintains TCP/IP, the underlying Internet protocol.

The World Wide Web Consortium. This industry-supported organization, whose founders include Web protocol inventor Tim Berners-Lee, fosters standards for the Web, including the Hypertext Transport Protocol (HTTP) that your Web browser and all Web servers use, Hypertext Markup Language (HTML), and other Web standards.

The Internet Corporation for Assigned Names and Numbers (ICANN), the private, non-profit corporation with responsibility for Internet address space allocation, protocol parameter assignment, domain name system management, and root server system management functions, the service previously performed by the Internet Assigned Numbers Authority.

InterNIC. This organization controls the assignment of domain names and their equivalent IP addresses. If we examine the minimum and maximum numerical value that can be stored in an IP (dot quad - 4 byte number) we see it can range from zero to 4,294,967,295 or approximately 5 billion, the current population of the Earth.

There are three classes of domain or network providers A, B and C. A class C provider is the more common, representative of most smaller local Internet Service providers. They can typically sell 254 unique addresses. The class B can offer 65,535 addresses and the class A - 16,777,215.

A typical ISP has 1000 customer. When 254 call at the same time, someone will get a busy signal. Each customer is assigned an IP number at the time they connect. They will be the only person in the world who has that number at that time. Its truly a unique identification. When they hang up, that IP is returned to the IP modem POOL to be reissued to the next caller. This is called dynamic IP addressing. Some services give you an IP that never changes, this is called a Static IP. The primary advantage in a static IP is having a fixed or permanent address on the Net - like your municipal house number. This makes DC or direct connect clients and servers very easy to use. This is sometimes called peer to peer communications such as Internet telephone/video and chat communications.

When you apply for a domain of your own such as garyraymond.com, you are given a static IP which is registered and paired with your URL (domain name) on the DNS server system.

For example to find "www.volvo.se" (the web server for Volvo in Sweden), DNS does the following:

1) Ask one of the 13 root DNS servers for the addresses of "se" DNS servers.

2) Ask one of these "se" DNS servers for the addresses of "volvo.se" DNS servers.

3) Ask one of these "volvo.se" DNS servers for the address of "www.volvo.se"

By iterating through the tree (starting at the root), DNS can find any address in the world based on this "root file".

Originated because of "cold war" security needs and U.S. defense research efforts, the Internet continues to be influenced by governments around the world. Some governments determine how accessible the Internet is and who can access it. Democratic governments are concerned about defense security, children's access to pornography, and the regulation of and provision of fair access to telecommunications infrastructure.

The Electronic Frontier Foundation. This organization leads the fight to protect free speech on the Internet.

Standards organizations. Standards foster order and stability. Foremost is the International Organization for Standardization (ISO). Among groups that contribute to standards development are the Institute of Electrical and Electronic Engineers. Many other organizations contribute to standards.

Inventors and product developers. The Internet is the result of the individual ideas of people like Vinton Cerf (TCP/IP) and Tim Berners-Lee (HTTP), teams and work groups of bright and devoted contributors, often supported by collaborating corporations such as Netscape, Microsoft, Sun Microsystems, IBM, and every company that produces a product you can use on the Internet.

Content developers. Not least, there has to be some reason to use the Internet. Content developers are the people who've built the millions and millions of Web pages.

Infrastructure providers. These include Internet service providers, your local phone company, possibly your cable TV company, and hundreds of companies that manufacture and put together the networks that make up the Internet.