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Excerpt: Subnetting, in short, can be thought of as an adjustable “slide rule” that tells the network infrastructure the logical size of a sub-network, or subnet. This is useful if you know how many IP addresses you’ll  to suit the needs of a predetermined number of PCs, so you can plan the size of your subnets to match that requirement. With IPv4, subnet masks are used to determine how big the subnets are. A standard IPv4 address requires 32 bits to describe it. These are commonly seen in the following format: 192.168.0.1 You’ve probably also seen these addresses accompanied by their “subnet masks”. A…