 Welcome to Dataflow on the Internet. The Internet is a worldwide collection of computers that are linked together. These global connections form a common wide area network, also known as the World Wide Web. This global connection allows you to exchange information with someone down the street or halfway around the world at any time of day, 365 days a year. Let's look at what happens when you press the Enter key on your computer and send information out to the World Wide Web. The information you send is broken into smaller pieces called data packets. This allows people around the world to use the Internet at the same time. Your information is sent through the Internet as small data packets and reassembled at the receiver's computer. Let's compare how data flows on the Internet to how cars travel on streets. The data packets from your computer are sent to your Internet service provider, or ISP, which sends them out to the Internet. Just as streets have speed limits for cars, the speed at which your data packets travel is dependent on your Internet connection. High-speed connections like DSL, wireless, and mobile broadband allow data packets to travel at faster speeds than slower connections like dial-up and older broadband. The speed at which your data packets travel is also dependent on the size of the data packets. Just like large trucks take longer to get up to speed and may travel at a slower speed, larger data packets travel more slowly and take longer to reach their destination. Each data packet contains a piece of your original information, as well as your IP address and the address for the destination computer. It might also contain a sequence number if the application you use to send the information is guaranteeing its delivery. The data packets may also contain other bits of information needed for controlling and checking their content. Just like cars may use different roads within a highway network to reach the same destination city, your data packets may use different routes within the Internet network to reach the same destination computer. In this example, all of the red cars have the same IP address. This means the cars have the same origin and destination. They are, however, all traveling on different paths to reach that destination. The Internet is a series of many interconnecting networks. To help manage traffic on your local roads, a traffic cop directs and monitors traffic. The Internet uses a router as its traffic cop. The router determines the best path for the data packets depending on the speed and number of other traveling data packets. Internet routers regularly communicate with each other so they know what routes provide the fastest delivery. These routes are stored inside the router's memory and are called routing tables. Just as traffic patterns can vary because of the amount of traffic, construction, and road conditions, Internet patterns can also vary depending on the amount, size, and type of data being sent. This means that your data packets may not always take the same path to reach their destination. In fact, some data packets may arrive out of sequence because of delays or they may not arrive at all. If you've ever used the Internet to listen to music or watch a video that cut out or looked pixelated, you've experienced high data traffic. Eventually, your data packets will reach the destination computer's ISP. Just as highways have on and off ramps, the local ISP is the destination computer's off ramp for your data packets. All ISPs have their own router that knows the final path to the destination computer. While these routers do interact with the Internet, their purposes are to know the fastest routes to the customer's computers and provide an on and off ramp to the Internet. When your data packets arrive at the destination computer, it starts the process of reassembling the packets. If the packets contain sequence numbers, the computer assembles them in the correct order and requests the retransmission of any packets that were lost during the journey. This concludes our journey of data flow over the Internet. A few key points to remember are all data is broken into smaller parts for transmission over the Internet. Not all data packets take the same route between the sending and receiving computers. The application used to send the information determines if the delivery of the data packets is guaranteed. The speed at which data packets travel is affected by Internet traffic. You have completed data flow on the Internet.