Summarization
Summarization allows the representation of a series of networks in a single summary address. At the top of the hierarchical design, the subnets in the routing table are more generalized. The subnet masks are shorter because they have aggregated the subnets lower in the network hierarchy. These summarized networks are often referred to as supernets, particularly when seen in the Internet as an aggregation of class addresses. They are also known as aggregated routes. The summarization of multiple subnets within a few subnets has several advantages. These include: reducing the size of the routing table; simplifying the recalculation of the network as the routing tables are smaller; network overhead scalability; and hiding network changes.