Learning objectives

Internet 101: Understanding How the Internet Works

1. Describe how the technologies of the Internet combine to answer these questions: What are you looking for? Where is it? And how do we get there?

2. Interpret a URL, understand what hosts and domains are, describe how domain registration works, describe cybersquatting, and give examples of conditions that constitute a valid and invalid domain-related trademark dispute.

3. Describe certain aspects of the Internet infrastructure that are fault-tolerant and support load balancing.

4. Discuss the role of hosts, domains, IP addresses, and the DNS in making the Internet work.

The Internet is a network of networks—millions of them, actually. If the network at your university, your employer, or in your home has Internet access, it connects to an Internet service provider (ISP). Many (but not all) ISPs are big telecommunications companies like Verizon, Comcast, and AT& T. These providers connect to one another, exchanging traffic, and ensuring your messages can get to any other computer that’s online and willing to communicate with you.

The Internet has no center and no one owns it. That’s a good thing. The Internet was designed to be redundant and fault-tolerant—meaning that if one network, connecting wire, or server stops working, everything else should keep on running. Rising from military research and work at educational institutions dating as far back as the 1960s, the Internet really took off in the 1990s, when graphical Web browsing was invented, and much of the Internet’s operating infrastructure was transitioned to be supported by private firms rather than government grants.

Enough history—let’s see how it all works! If you want to communicate with another computer on the Internet then your computer needs to know the answer to three questions: What are you looking for? Where is it? And how do we get there? The computers and software that make up Internet infrastructure can help provide the answers. Let’s look at how it all comes together.

The URL: “What Are You Looking For? ”

When you type an address into a Web browser (sometimes called a URL for uniform resource locator), you’re telling your browser what you’re looking for. Figure 12.2 " Anatomy of a Web Address" describes how to read a typical URL.

Figure 12.2 Anatomy of a Web Address

The URL displayed really says, “Use the Web (https://) to find a host server named ‘www’ in the ‘nytimes.com’ network, look in the ‘tech’ directory, and access the ‘index.html’ file.”

The https:// you see at the start of most Web addresses stands for hypertext transfer protocol. A protocol is a set of rules for communication—sort of like grammar and vocabulary in a language like English. The http protocol defines how Web browser and Web servers communicate and is designed to be independent from the computer’s hardware and operating system. It doesn’t matter if messages come from a PC, a Mac, a huge mainframe, or a pocket-sized smartphone; if a device speaks to another using a common protocol, then it will be heard and understood.

The Internet supports lots of different applications, and many of these applications use their own application transfer protocol to communicate with each other. The server that holds your e-mail uses something called SMTP, or simple mail transfer protocol, to exchange mail with other e-mail servers throughout the world. FTP, or file transfer protocol, is used for—you guessed it—file transfer. FTP is how most Web developers upload the Web pages, graphics, and other files for their Web sites. Even the Web uses different protocols. When you surf to an online bank or when you’re ready to enter your payment information at the Web site of an Internet retailer, the http at the beginning of your URL will probably change to https (the “s” is for secure). That means that communications between your browser and server will be encrypted for safe transmission. The beauty of the Internet infrastructure is that any savvy entrepreneur can create a new application that rides on top of the Internet.