Ip Concepts; Ip Addresses - D-Link DSL-504 User Manual

DSL-504 ADSL Router User's Guide
B

IP Concepts

This appendix describes some basic IP concepts, the TCP/IP addressing scheme
and show how to assign IP Addresses.
When setting up the Router, you must make sure it has a valid IP address. Even
if you will not use the WAN port (ADSL port), you should, at the very least, make
sure the Ethernet LAN port is assigned a valid IP address. This is required for
telnet, in-band SNMP management, and related functions such as "trap"
handling and TFTP firmware download.

IP Addresses

The Internet Protocol (IP) was designed for routing data between network sites
all over the world, and was later adapted for routing data between networks
within any site (often referred to as "subnetworks" or "subnets"). IP includes a
system by which a unique number can be assigned to each of the millions of
networks and each of the computers on those networks. Such a number is called
an IP address.
To make IP addresses easy to understand, the originators of IP adopted a system
of representation called "dotted decimal" or "dotted quad" notation. Below are
examples of IP addresses written in this format:
201.202.203.204 189.21.241.56 125.87.0.1
Each of the four values in an IP address is the ordinary decimal (base 10)
representation of a value that a computer can handle using eight "bits" (binary
digits — 1s and 0s). The dots are simply convenient visual separators.
Zeros are often used as placeholders in dotted decimal notation; 189.21.241.56
can therefore also appear as 189.021.241.056.
IP networks are divided into three classes on the basis of size. A full IP address
contains a network portion and a "host" (device) portion. The network and host
portions of the address are different lengths for different classes of networks, as
shown in the table below.
57