Appendix B IP Addresses and Subnetting

The following figure shows the company network before subnetting.

Figure 183 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.

The following figure shows the company network after subnetting. There are now two sub-networks, A and B.

Figure 184 Subnetting Example: After Subnetting

 

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VSG1432-B101 Series User’s Guide