3com 520 User Manual

 

 

B

 

R

 

I

 

D

 

G

 

I

 

N

 

G

 

 

 

A

 

N

 

D

 

 R

 

O

 

U

 

T

 

I

 

N

 

G

 

 

TCP/IP Numbering and subnet masking IP numbers 

 

or 

 

 are normally made up of four fields 

 

(normally called 

 

), with each byte having a 

 

whole number value of between 0 and 255, and the 

 

bytes separated by a full stop. For example:

123.123.123.123

 

An IP address is divided into two sections, one is the 

 

section and the other is the 

 

 

 

 section. For example:

123.123.|123.123

 

Network Host 

 

The divider | between the two sections is moveable 

 

according to what 

 

 of IP address it is. The class of 

 

address is defined by what the number is in the first 

 

address byte:

■

 

For a Class A IP address the number in the first byte 

 

will be in the range 00 to 126 

■

 

For a Class B IP address the numbers in the first & 

 

second bytes will be in the range 128.001 to 191.254

■

 

For a Class C IP address the numbers in the first, 

 

second & third bytes will be in the range 192.000.001 

 

to 223.255.254 

 

For example:

 

Class A

1.|123.123.123

 

Network Host 

 

Class B

128.001.|123.123

 

Network Host 

 

Class C

192.123.123.|123

 

Network Host 

 

Using of any of the address classes in a private 

 

TCP/IP network is not a problem, providing that 

 

connections outside of that private network to 

 

external public or private TCP/IP networks are never 

 

needed. If a private IP addressing number scheme is 

 

established within a private corporate network, 

 

connections out of that network to external public or 

 

other private TCP/IP networks, can be achieved via a 

 

computer which has software which enables it to 

 

act as an IP 

 

. These devices, if configured 

 

correctly, provide the IP numbering/address 

 

translation between the two networks. 

Rc.bk : RCAPPA.FRM  Page 12  Thursday, July 10, 1997  9:53 AM