it1080c computer networking ipv4 addressing lab 1 classful addressing when the internet protocol was developed, the internet contains a few large physical networks and many small networks so designers chose an addressing scheme to accommodate a combination of large and small networks. the original classful ip addressing divided ip address space into three primary classes and each class has a different size prefix and suffix. the first four bits of an ip address determined class to which the address belonged and specifies how the remainder of the address was divided into prefix and suffix. class first four bits first octet