Example: Four Subnets; Table 91 Subnet 1; Table 92 Subnet 2; Table 93 Subnet 3 - ZyXEL Communications PRESTIGE 2602R Series User Manual

192.168.1.0 with mask 255.255.255.128 is the subnet itself, and 192.168.1.127 with mask
255.255.255.128 is the directed broadcast address for the first subnet. Therefore, the lowest IP
address that can be assigned to an actual host for the first subnet is 192.168.1.1 and the highest
is 192.168.1.126. Similarly the host ID range for the second subnet is 192.168.1.129 to
192.168.1.254.

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 of 00, 01, 10 and 11. The subnet
mask is 26 bits (11111111.11111111.11111111.11000000) or 255.255.255.192. Each subnet
contains 6 host ID bits, giving 2
1's is the broadcast address on the subnet).

Table 91 Subnet 1

IP Address
IP Address (Binary)
Subnet Mask (Binary)
Subnet Address: 192.168.1.0
Broadcast Address:
192.168.1.63

Table 92 Subnet 2

IP Address
IP Address (Binary)
Subnet Mask (Binary)
Subnet Address: 192.168.1.64
Broadcast Address: 192.168.1.127

Table 93 Subnet 3

IP Address
IP Address (Binary)
Subnet Mask (Binary)
Appendix C IP Subnetting
6
-2 or 62 hosts for each subnet (all 0's is the subnet itself, all
NETWORK NUMBER
192.168.1.
11000000.10101000.00000001.
11111111.11111111.11111111.
Lowest Host ID: 192.168.1.1
Highest Host ID: 192.168.1.62
NETWORK NUMBER
192.168.1.
11000000.10101000.00000001.
11111111.11111111.11111111.
Lowest Host ID: 192.168.1.65
Highest Host ID: 192.168.1.126
NETWORK NUMBER
192.168.1.
11000000.10101000.00000001.
11111111.11111111.11111111.
Prestige 2602R Series User's Guide
LAST OCTET BIT
VALUE
0
00000000
11000000
LAST OCTET BIT
VALUE
64
01000000
11000000
LAST OCTET BIT
VALUE
128
10000000
11000000
296