Calling the Internet! Calling the Internet!

Calling the Internet! Calling the Internet!

Let's face it: Practically everyone on the planet knows about the Internet. But we all probably have our own opinions about what the Internet is and is not. One definition of the Internet is that it is an IP packet forwarding service. The Internet is a bunch of networking devices, cables, and software, which collectively try to forward IP packets to their correct destination IP host.

As mentioned earlier, the Internet includes Enterprise networks, home users, ISPs and their networks, as well as all the connections between them. If you think of the Internet as an IP packet forwarding service, each Enterprise will want to have at least one router that can route packets to and from an ISP router. For instance, by using a point-to-point WAN link between a router in an Enterprise network and a router in an ISP network, the two routers can route IP packets back and forth.

Ultimately, the WAN link just lets the routers forward packets. And as long as each Enterprise network has some form of WAN link between itself and an ISP, the Enterprise can communicate with the Internet.

The rest of this chapter focuses on ways you can connect to the Internet from home. After you're connected, all your PC needs to do is send and receive IP packets so that your applications will work. Essentially, once your PC can send and receive IP packets with an ISP, it has become a part of the global Internet.