ZyXEL WAP3205 Manuel d'utilisateur télécharger pdf (Page 130)

Appendix B IP Addresses and Subnetting

WAP3205 v2 User’s Guide

130

Figure 92 Network Number and Host ID

How much of the IP address is the network number and how much is the host ID varies according

to the subnet mask.

Subnet Masks

A subnet mask is used to determine which bits are part of the network number, and which bits are

part of the host ID (using a logical AND operation). The term “subnet” is short for “sub-network”.

A subnet mask has 32 bits. If a bit in the subnet mask is a “1” then the corresponding bit in the IP

address is part of the network number. If a bit in the subnet mask is “0” then the corresponding bit

in the IP address is part of the host ID.

The following example shows a subnet mask identifying the network number (in bold text) and host

ID of an IP address (192.168.1.2 in decimal).

By convention, subnet masks always consist of a continuous sequence of ones beginning from the

leftmost bit of the mask, followed by a continuous sequence of zeros, for a total number of 32 bits.

Subnet masks can be referred to by the size of the network number part (the bits with a “1” value).

For example, an “8-bit mask” means that the first 8 bits of the mask are ones and the remaining 24

bits are zeroes.

Table 50 IP Address Network Number and Host ID Example

1ST OCTET:

(192)

2ND

OCTET:

(168)

3RD

OCTET:

(1)

4TH OCTET

(2)

IP Address (Binary) 11000000 10101000 00000001 00000010

Subnet Mask (Binary) 11111111 11111111 11111111 00000000

Network Number 11000000 10101000 00000001

Host ID 00000010

1 2 ... 125 126 127 128 129 130 131 132 133 134 135 ... 193 194

Pas de commentaire

ZyXEL WAP3205 Manuel d'utilisateur Page 130