Subnetting With Class A And Class B Networks - ZyXEL Communications ZyXEL ZyWALL 2WE User Manual

SUBNET SUBNET ADDRESS
8 224
The following table is a summary for class "C" subnet planning.
NO. "BORROWED" HOST BITS
1
2
3
4
5
6
7

Subnetting With Class A and Class B Networks.

For class "A" and class "B" addresses the subnet mask also determines which bits are part of the network
number and which are part of the host ID.
A class "B" address has two host ID octets available for subnetting and a class "A" address has three host ID
octets (see Chart K-1) available for subnetting.
The following table is a summary for class "B" subnet planning.
NO. "BORROWED" HOST BITS
1
2
3
IP Subnetting
Chart K-11 Eight Subnets
FIRST ADDRESS
223
Chart K-12 Class C Subnet Planning
SUBNET MASK
255.255.255.128 (/25)
255.255.255.192 (/26)
255.255.255.224 (/27)
255.255.255.240 (/28)
255.255.255.248 (/29)
255.255.255.252 (/30)
255.255.255.254 (/31)
Chart K-13 Class B Subnet Planning
SUBNET MASK
255.255.128.0 (/17)
255.255.192.0 (/18)
255.255.224.0 (/19)
ZyWALL 2 and ZyWALL 2WE
LAST ADDRESS BROADCAST ADDRESS
254
NO. SUBNETS NO. HOSTS PER SUBNET
2
4
8
16
32
64
128
NO. SUBNETS NO. HOSTS PER SUBNET
2
4
8
255
126
62
30
14
6
2
1
32766
16382
8190
51