IP route summarization is a mechanism used to design networks that are more flexible and perform better. Although some routing protocols summarize only at the boundaries of major network numbers, others support route summarization (aggregation) at any bit boundary. Variable-length subnet masks enable routing protocols to summarize on bit boundaries. This aggregation process can work hand-in-hand with VLSM to build hierarchically structured networked environments. The following are some of the many advantages to summarizing addresses into a hierarchy:
Reduces the amount of information stored in routing tables
Allocates an existing pool of addresses more economically
Makes the routing process more efficient
Lessens the load on ...