At Merit, the internal router must be told how much of that string of numbers identifies the network and how much of that string identifies the host. When a Class C network is not subnetted, the first three octets indicate the network and the last octet indicates the host. With no subnets, and the last eight bits identifying the host, the default subnet mask of 255.255.255.0 is used. The subnet mask tells the router inside the network which of those 32 bits represent the network number and which represent the host number. Then, the router compares the address it was given to the subnet mask.
Any bit set to zero in the subnet mask blocks the number from appearing in the network address.
One network is identified and the address above identifies host number 129 on that network. In this case, any one of 256 host addresses can be assigned to a device because the network is not subnetted. The router in the network can reach all 256 hosts on this network. 198.108.60.0 and 198.108.60.255 are not used for host addresses. Two subnets Suppose, the network is divided into two subnets.