Subnetting

Subnetting - process of taking a large network and spitting it up into many individual and smaller subnetworks, or subnets

Subnet Masks - 32-bit numbers that are normally written out as 4 octets in decimal

Your IP address is 192.168.8.34, and your subnet mask is 255.255.0.0. What part of the subnet mask represents the subnet ID?

In this case, the last two octets represent the host ID. The first two octets in the subnet mask are all ones in binary (11111111,11111111). This tells the router that the first two octets of the IP address are the subnet ID.

You always lose two host IDs per network. For example, the subnet mask of 255.255.255.0 has the last octet available for host IDs (256 potential hosts). But remember, zero is generally not used, and 255 is normally reserved as a broadcast address. This means that, really, only the numbers 1-254 are available for assignment to a host.