two logical plane :

control plane : building a RIB

forwarding plane:

two major functions :

    packet classification :process of condense RIB into a forwarding information base \(FIB\)

    packet forwarding 

memory cost :

main is the BGP router process : three major components, route map, filter list caches

• BGP RIB---network entries,path entries,path attribute
• IP RIB for BGP learned prefix
• IP switching component for BGP learned prefixes