THE INTERNET PROTOCOL (IP)

A wire can get data from one place to another. However, you already know that the Internet can get data to many different places, distributed all over the world. How does that happen? The different pieces of the Internet are connected by a set of computers called routers, which connect networks together. These networks are sometimes Ethernets; sometimes token rings, and sometimes telephone line.
The telephone lines and Ethernets are equivalent to the trucks and planes of the Postal Service. They are means by which mail is moved from place to place. The routers are postal substations; they make decisions about how to route data ("packets"), just like a postal substation decides how to "route" envelopes containing mail.
Each substation or router does not have a connection to every other one. If you put an envelope in the mail in Dixville Notch, New Hampshire, addressed to Boonville, California, the Post Office doesn't reserve a plane from New Hampshire to California to carry it.
The local Post Office sends it to a substation; the substation sends it to another substation; and so on, until it reaches the destination. That is, each sub-station only needs to know what connections are available, and what is the best "next hop" to get a packet closer to its destination. Similarly, with the Internet: a router looks at where your data is going and decides where to send it next. It just decides which pipe is best and uses it.