Appendix E IP Subnetting

P-660HWP-Dx User’s Guide 39
Example: Four Subnets

The above example illustrated using a 25-bit subnet mask to divide a class “C” address space

into two subnets. Similarly to divide a class “C” address into four subnets, you need to

“borrow” two host ID bits to give four possible combinations (00, 01, 10 and 11). The subnet

mask is 2 6 bits (11111111 .11111111.11111111.11000000) or 255.25 5.255.192. Each subnet

contains 6 host ID bits, giving 26-2 or 62 hosts for each subnet (all zeroes is the subnet itself,

all ones is the broadcast address on the subnet).

Table 161 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 (Binary) 11111111.11111111. 11111111. 11000000
Subnet Address: 192.168.1.0 Lowest Host ID: 192.168.1.1
Broadcast Address:
192.168.1.63
Highest Host ID: 192.168.1.62

Table 162 Subnet 2

IP/SUBNET MASK NETWORK NUMBER LAST OCTET BIT
VALUE
IP Address 192.168.1. 64
IP Address (Binary) 11000000.10101000.00000001. 01000000
Subnet Mask (Binary) 11111111.11111111. 11111111. 11000000
Subnet Address: 192.168.1.64 Lowest Host ID: 192.168.1.65
Broadcast Address: 192.168.1.127 Highest Host ID: 192.168.1.126

Table 163 Subnet 3

IP/SUBNET MASK NETWORK NUMBER LAST OCTET BIT
VALUE
IP Address 192.168.1. 128
IP Address (Binary) 11000000.10101000.00000001. 10000000
Subnet Mask (Binary) 11111111.11111111. 11111111. 11000000
Subnet Address:
192.168.1.128
Lowest Host ID: 192.168.1.129
Broadcast Address:
192.168.1.191
Highest Host ID: 192.168.1.190

Table 164 Subnet 4

IP/SUBNET MASK 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