ZyXEL Communications P-660HWP-D1, User Manual

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Appendix D IP Subnetting
P-660HWP-D1 User’s Guide
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In the following charts, shaded/bolded last octet bit values indicate host ID bits
“borrowed” to make network ID bits. The number of “borrowed” host ID bits
determines the number of subnets you can have. The remaining number of host
ID bits (after “borrowing”) determines the number of hosts you can have on
each subnet.
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
7
– 2 or 126 hosts 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.
Table 148 Subnet 1
IP/SUBNET MASK NETWORK NUMBER
LAST OCTET BIT
VALUE
IP Address 192.168.1. 0
IP Address (Binary) 11000000.10101000.00000001. 0 0000000
Subnet Mask 255.255.255. 128
Subnet Mask (Binary) 11111111.11111111.11111111. 1 0000000
Subnet Address: 192.168.1.0 Lowest Host ID: 192.168.1.1
Broadcast Address:
192.168.1.127
Highest Host ID: 192.168.1.126
Table 149 Subnet 2
IP/SUBNET MASK NETWORK NUMBER LAST OCTET BIT VALUE
IP Address 192.168.1. 128
IP Address (Binary) 11000000.10101000.00000001. 1 0000000
Subnet Mask 255.255.255. 128
Subnet Mask (Binary) 11111111.11111111.11111111. 1 0000000
Subnet Address:
192.168.1.128
Lowest Host ID: 192.168.1.129
Broadcast Address:
192.168.1.255
Highest Host ID: 192.168.1.254