How Routers Send Data to Their Destination


How Routers Send Data to Their Destination

A router has input ports for receiving IP packets and output ports for sending those packets toward their destinations. When a packet comes to an input port, the router examines the packet header and checks the destination in it against a routing tablea database that tells the router how to send packets to various destinations.



 


Part 2: Connecting to the Internet

 

You can connect to the Internet in many waysand many more ways pop up practically every day. They range from simple telephone dial-in connections to high-speed cable and digital subscriber lines (DSL) to satellite connections, TV connections, wireless connections, connections at work and home via local area networks (LANs), and even connections via cellular telephones. This part of the book looks at the myriad ways people and computers gain access to the Internet.

One general rule is true about Internet connections: the faster, the better. People want the fastest connection possible because many pictures, sounds, and videos are available on the Internet. Today, the three most common ways you can connect to the Internet are through a corporate or university LAN, at home via a cable modem or DSL modem, or over telephone lines. Increasingly important, though, are wireless connections via the WiFi networking standard. Direct connections over LANs are generally the fastest connection, cable modems and DSL modems are the second fastest, and telephone-line connections the slowest. Cable modems, DSL modems, and LAN connections are all very high-speed connections, and are known as broadband connections.

This section looks at the ways computers can connect to the Internet. Chapter 7, "How Computers Connect to the Internet," provides an overview of the types of Internet connections that are possible. Not only will you examine various kinds of network connections and phone-line connections, but you'll also look at newer, high-speed DSL connections as well.

Chapter 8, "How Internet/Television Connections Work," looks at what might become one of the primary ways many of us connect to the Internetthrough some type of television connection. This chapter looks at how cable modems work, and peers inside a newer technologyInternet-enhanced TVthat adds interactivity to your television set and makes your Internet experience more compelling. It also looks at what some believe is the future of the Internet and television, IPTV.

Chapter 9, "How Wireless Connections and WiFi Work," looks at how you can make an Internet connection without wires. Some common ones include using a satellite dish, much like the one now used for satellite TV, and using cell phones. But the most common wireless connection of all is known as WiFi, a standard that allows you to hook up without wires to the Internet at home, at work, or at many public hot spots. A laptop or PC equipped with a wireless network adapter can access the Internet without being physically connected to a networkWiFi routers connect you. In addition, a newer technology called WiMax allows anyone in a metropolitan region to connect as well.

Chapter 10, "How Home Networks Work," examines a fast-growing phenomenonusing networks at home to connect to the Internet. Many homes have more than one computer, and users want to be able to share a high-speed connection, such as a cable or DSL modem. Home networks make that possible. And increasingly, other devices at home will be connected to the Internet, not just PCsand this chapter looks at them as well.

As you'll see in this part of the book, connecting to the Internet will become increasingly easyand at increasingly higher speeds. Not only can you do things more quickly on the Internet, but you can access entirely new services that contain video, animation, and other high-bandwidth content. And as more places install wireless hardware, the Internet can be accessed anywherenot just when you happen to be sitting in front of a PC connected to a network or phone line.


 

Chapter 7: How Computers Connect to the Internet

 

Chapter 8: How Internet/Television Connections Work

 

Chapter 9: How Wireless Connections and WiFI Work

 

Chapter 10: How Home Networks Work