ZyXEL Communications Internet Security Gateway ZyWALL 2 Series - Manual (Page 566)

ZyWALL 2 Series User’s Guide
I-6 IP Subnetting
Chart I-10 Subnet 4
NETWORK NUMBER LAST OCTET BIT VALUE
IP Address 192.168.1. 192
IP Address (Binary) 11000000.10101000.00000001. 11000000
Subnet Mask (Binary) 11111111.11111111.11111111. 11000000
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