hi In OSPF , its split in to areas for concentrating the LSA updates in to one area  without traversing to other area , why a hierarchial design was made , as a central backbone area , to which all other areas are connected .

hi  why BGP is using TCP ,for session establishment , as other routing protocols  such as OSPF is not using it

OSPF is  link state routiing protocol , any change in the topology is updated by th lsa at the moment change is happened and LSDB is updated, if there is no change in the topology  why OSPF is refresing the LSDB  after every 30 minutes RegardsBinoj

hi two routers are connected  and ospf is enabled , after creating adjacency , how router is knowing that hello packet is a just a hello packet  to keep the adjacency up  . RegardsBinoj