The Border Gateway Protocol （BGP）is an interautonomous system（）protocol.The primary function of a BGP speaking system is to exchange network （）information with other BGP system.This network reachability information includes information on the list of Autonomous System（ASs）that reachability  information  traverses.BGP-4 provides a new set of mechanisms for supporting （）interdomain routing.These mechanisms include support for advertising an IP （）and eliminate the concept of network class within BGP.BGP-4 also introduces mechanisms that allow aggregation of routes， including （）of AS paths.These changes provide support for the proposed supernettting scheme.