Table 89 Subnet 1; Table 90 Subnet 2 - ZyXEL Communications PRESTIGE 2602R Series User Manual

Prestige 2602R Series User's Guide
The first three octets of the address make up the network number (class "C"). You want to
have two separate networks.
Divide the network 192.168.1.0 into two separate subnets by converting one of the host ID bits
of the IP address to a network number bit. The "borrowed" host ID bit can be either "0" or "1"
thus giving two subnets; 192.168.1.0 with mask 255.255.255.128 and 192.168.1.128 with
mask 255.255.255.128.
Note: In the following charts, shaded/bold last octet bit values indicate host ID bits
"borrowed" to form 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.

Table 89 Subnet 1

IP Address
IP Address (Binary)
Subnet Mask
Subnet Mask (Binary)
Subnet Address: 192.168.1.0
Broadcast Address:
192.168.1.127

Table 90 Subnet 2

IP Address
IP Address (Binary)
Subnet Mask
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
or 126 hosts for each subnet.
295
NETWORK NUMBER
192.168.1.
11000000.10101000.00000001.
255.255.255.
11111111.11111111.11111111.
Lowest Host ID: 192.168.1.1
Highest Host ID: 192.168.1.126
NETWORK NUMBER
192.168.1.
11000000.10101000.00000001.
255.255.255.
11111111.11111111.11111111.
Lowest Host ID: 192.168.1.129
Highest Host ID: 192.168.1.254
LAST OCTET BIT
VALUE
0
00000000
128
10000000
LAST OCTET BIT VALUE
128
10000000
128
10000000
7
Appendix C IP Subnetting
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