Chart H-7 Subnet 1; Chart H-8 Subnet 2 - ZyXEL Communications VANTAGE RADIUS 50 User Manual

Subnet Mask (Binary)
Subnet Address: 192.168.1.128
Broadcast Address: 192.168.1.255
The remaining 7 bits determine the number of hosts each subnet can have. Host IDs of all zeros
represent the subnet itself and host IDs of all ones are the broadcast address for that subnet, so the
actual number of hosts available on each subnet in the example above is 2
each subnet.
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
6
bits, giving 2 -2 or 62 hosts for each subnet (all 0's is the subnet itself, all 1's is the broadcast
address on the subnet).
IP Address
IP Address (Binary)
Subnet Mask (Binary)
Subnet Address: 192.168.1.0
Broadcast Address: 192.168.1.63
IP Subnetting
11111111.11111111.11111111.
Lowest Host ID: 192.168.1.129
Highest Host ID: 192.168.1.254

Chart H-7 Subnet 1

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

Chart H-8 Subnet 2

NETWORK NUMBER
Vantage RADIUS User's Guide
10000000
7
– 2 or 126 hosts for
LAST OCTET BIT VALUE
0
00000000
11000000
LAST OCTET BIT VALUE
H-5