Table 71 Subnet 2 - ZyXEL Communications P-660R-D Series User Manual

Table 71 Subnet 2 (continued)
IP/SUBNET MASK
Subnet Address:
192.168.1.128
Broadcast Address:
192.168.1.255
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
for 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 (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,
6
giving 2 -2 or 62 hosts for each subnet (all zeroes is the subnet itself, all ones is the broadcast address on
the subnet).
Table 72 Subnet 1
IP/SUBNET MASK
IP Address
IP Address (Binary)
Subnet Mask (Binary)
Subnet Address: 192.168.1.0
Broadcast Address:
192.168.1.63
Table 73 Subnet 2
IP/SUBNET MASK
IP Address
IP Address (Binary)
Subnet Mask (Binary)
Subnet Address: 192.168.1.64
Broadcast Address: 192.168.1.127
Appendix E IP Addresses and Subnetting
NETWORK NUMBER
Lowest Host ID: 192.168.1.129
Highest Host ID: 192.168.1.254
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
P-660R-D Series User's Guide
LAST OCTET BIT VALUE
7
LAST OCTET BIT
VALUE
0
00000000
11000000
LAST OCTET BIT
VALUE
64
01000000
11000000
– 2 or 126 hosts
5