Subnetting and Supernetting

Intro
When a large network is subnetted, the network is divided into at least two smaller subnetworks, with each subnetwork (subnet) having its own subnetwork address (subnetid). When supernetting is performed, several small Class C networks are combined to create one large network, or supernetwork.

Differences:
Subnetting is the process of dividing an IP network in to sub divisions called subnets whereas, Supernetting is the process of combining several IP networks with a common network prefix. Supernetting will reduce the number of entries in a routing table and also will simplify the routing process. In subnetting, host ID bits (for IP addresses from a single network ID) are borrowed to be used as a subnet ID, while in supernetting, bits from the network ID are borrowed to be used as the host ID.