Zyxel-communications G.SHDSL.bis 4-port Security Gateway P-793H Manual do Utilizador descarregar pdf (Página 396)

P-793H User’s Guide

396 Appendix F IP Addresses and Subnetting

The first mask shown is the class “C” natural mask. Normally if no mask is specified it is

understood that the natural mask is being used.

Example: Two Subnets

As an example, you have a class “C” address 192.168.1.0 with subnet mask of 255.255.255.0.

The first three octets of the address make up the network number (class “C”). You want to

have two separate networks.

Divide the network 192.168.1.0 into two separate subnets by converting one of the host ID bits

of the IP address to a network number bit. The “borrowed” host ID bit can be either “0” or “1”

thus giving two subnets; 192.168.1.0 with mask 255.255.255.128 and 192.168.1.128 with

mask 255.255.255.128.

Note: In the following charts, shaded/bolded last octet bit values indicate host ID bits

“borrowed” to form network ID bits. The number of “borrowed” host ID bits determines

the number of subnets you can have. The remaining number of host ID bits (after

“borrowing”) determines the number of hosts you can have on each subnet.

255.255.255.248 /29 1111 1000

255.255.255.252 /30 1111 1100

Table 143 Alternative Subnet Mask Notation (continued)

SUBNET MASK SUBNET MASK “1” BITS LAST OCTET BIT VALUE

Table 144 Two Subnets Example

IP/SUBNET MASK NETWORK NUMBER HOST ID

IP Address 192.168.1. 0

IP Address (Binary) 11000000.10101000.00000001. 00000000

Subnet Mask 255.255.255. 0

Subnet Mask (Binary) 11111111.11111111.11111111. 00000000

Table 145 Subnet 1

IP/SUBNET MASK NETWORK NUMBER

LAST OCTET BIT

VALUE

IP Address 192.168.1. 0

IP Address (Binary) 11000000.10101000.00000001. 00000000

Subnet Mask 255.255.255. 128

Subnet Mask (Binary) 11111111.11111111.11111111. 10000000

1 2 ... 391 392 393 394 395 396 397 398 399 400 401 ... 431 432

Sem comentários

Zyxel-communications G.SHDSL.bis 4-port Security Gateway P-793H Manual do Utilizador Página 396