WEBBITS explains the Internet:
TCP/IP explained 
TCP/IP is the protocol (or set of rules) to allow different computers to transfer data between each other to send e-mail, handle logons, transfer files, etc.

IP stands for Internet Protocol.
It is a method for finding the best route to send data between computers.

TCP stands for Transmission Control Protocol and requires that the sending and receiving machines are connected with each other at all times, and acknowledge each message sent between them.

IP Addresses:
Domain Names are used on the Internet to represent IP addresses.  These IP addresses are stored as numbers instead of names.  In order for the Internet to know where in the world to find the site that you are looking for, the IP address for that Domain Name must first be found by looking up a table of all registered Domain Names.

For example, the address:       www.aei.ca
Represents the IP address:      206.123.6.1

An IP address is 32 bits long, broken into four 8-bit parts.  Each 8-bit part can represent numbers from 0 to 255.  The dotted quad notation separates each part by a period, e.g. 147.120.3.28

The largest number for any site can be 255.255.255.255.

This allows for over four billion possible addresses, but in reality, there are actually less than this because some combinations are used to indicate the type of network.

An IP address has two parts to it:

A company site may have more than one host computer on its network site, and the last part of the number is the host number at that site.

The larger the site, the more digits that are reserved for host computers on that network site.

Class A sites have the last 9 digits for host computers
Class B sites have the last 6 digits for host computers
Class C sites have the last 3 digits for host computers

You can tell which Class a site belongs to by looking at the first group of three digits in the address:

Class A addresses are between 0 and 127
Class B addresses are between 128 and 191
Class C addresses are between 192 and 223

Examples:
147.14.87.23 is a Class B network, host # = 87.23
221.132.3.123 is a Class C network, host # = 123

Web Addressses using IPs
You can enter someone's Web page address by using either its domain name or its IP address.  e.g.

It is better to use the domain name because an Internet resource can be moved to another computer which has a different IP address, but the same domain name may still apply.

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The bird illustrations, adapted by me for use here, are from the IBM DOS User's Guide, 1983
Copyright on text and layouts © 1997 Margaret Brown