ZyWALL 2 Series User’s Guide

Chart I-10 Subnet 4

 

NETWORK NUMBER

 

 

LAST OCTET BIT VALUE

 

 

 

 

 

 

IP Address

192.168.1.

 

192

 

 

 

 

 

 

IP Address (Binary)

11000000.10101000.00000001.

 

 

000000

11

 

 

 

 

 

 

Subnet Mask (Binary)

11111111.11111111.11111111.

 

 

000000

11

 

 

 

 

 

 

Subnet Address: 192.168.1.192

 

Lowest Host ID: 192.168.1.193

 

 

 

Broadcast Address: 192.168.1.255

 

Highest Host ID: 192.168.1.254

 

 

 

 

 

 

Example Eight Subnets

Similarly use a 27-bit mask to create 8 subnets (001, 010, 011, 100, 101, 110).

The following table shows class C IP address last octet values for each subnet.

Chart I-11 Eight Subnets

SUBNET

SUBNET ADDRESS

FIRST ADDRESS

LAST ADDRESS

BROADCAST ADDRESS

 

 

 

 

 

1

0

1

30

31

 

 

 

 

 

2

32

33

62

63

 

 

 

 

 

3

64

65

94

95

 

 

 

 

 

4

96

97

126

127

 

 

 

 

 

5

128

129

158

159

 

 

 

 

 

6

160

161

190

191

 

 

 

 

 

7

192

193

222

223

 

 

 

 

 

8

224

223

254

255

 

 

 

 

 

The following table is a summary for class “C” subnet planning.

Chart I-12 Class C Subnet Planning

NO. “BORROWED” HOST BITS

SUBNET MASK

NO. SUBNETS

NO. HOSTS PER SUBNET

 

 

 

 

1

255.255.255.128 (/25)

2

126

 

 

 

 

2

255.255.255.192 (/26)

4

62

 

 

 

 

3

255.255.255.224 (/27)

8

30

 

 

 

 

I-6

IP Subnetting