Establishing the telephone connection consists first of dialing the number. Then the person you called
answers, ???Hello,??? and then you say, ???Hi, this is George.??? Your connection is established.
The protocol following a connection on the phone is for one person to speak, and then the other. If two
people speak at once, we expect both to stop speaking, and then listen for the other to begin again, after a short
interval. Computer protocols are sometimes quite analogous to such human behavior.
Computer networks can be classified based on their size. A small network that connects computers contained
in a single room, floor, or a single building is called a local area network (LAN). LANs have become very
commonplace, and you may have a LAN in your home. A LAN is typically owned by an individual and
connects computers that are relatively close together.
A wide area network (WAN) covers a large geographical distance. For example a WAN may span several
cities, several states, or an entire country. A WAN, unlike a LAN, is typically owned and maintained by an
organization and has the capacity to carry large amounts of data.
To understand the difference between a LAN and a WAN, consider for a moment the pipes that carry water
to your house.
Pages:
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351