ZyXEL FSG1100HN User Guide - Page 118

Subnetting, Subnetting Example: Before Subnetting

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Appendix B IP Addresses and Subnetting Subnetting You can use subnetting to divide one network into multiple sub-networks. In the following example a network administrator creates two sub-networks to isolate a group of servers from the rest of the company network for security reasons. In this example, the company network address is 192.168.1.0. The first three octets of the address (192.168.1) are the network number, and the remaining octet is the host ID, allowing a maximum of 28 - 2 or 254 possible hosts. The following figure shows the company network before subnetting. Subnetting Example: Before Subnetting You can "borrow" one of the host ID bits to divide the network 192.168.1.0 into two separate sub-networks. The subnet mask is now 25 bits (255.255.255.128 or /25). The "borrowed" host ID bit can have a value of either 0 or 1, allowing two subnets; 192.168.1.0 /25 and 192.168.1.128 /25. 118 FSG1100HN User's Guide

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Appendix B IP Addresses and Subnetting
FSG1100HN User’s Guide
118
Subnetting
You can use subnetting to divide one network into multiple sub-networks. In the
following example a network administrator creates two sub-networks to isolate a
group of servers from the rest of the company network for security reasons.
In this example, the company network address is 192.168.1.0. The first three
octets of the address (192.168.1) are the network number, and the remaining
octet is the host ID, allowing a maximum of 2
8
– 2 or 254 possible hosts.
The following figure shows the company network before subnetting.
Subnetting Example: Before Subnetting
You can “borrow” one of the host ID bits to divide the network 192.168.1.0 into
two separate sub-networks. The subnet mask is now 25 bits (255.255.255.128
or /25).
The “borrowed” host ID bit can have a value of either 0 or 1, allowing two
subnets; 192.168.1.0 /25 and 192.168.1.128 /25.