DBD (Database Description or Type2 OSPF Packet) is a sort of summary of the OSPF Database in a router. DBD is used to check if the LSDB between 2 routers is the same. These packets are exchanged when an adjacency is being initialized. They describe the topology information a router has in its database. DBD uses poll-response procedure (master/slave). Master sends DBD packets/polls which are acknowledged by the slave.       Consider the simple below topology with two Routers: As soon as we enable OSPF on the router interfaces, it starts exchanging Hello and DBD Packets. It is obvious … Continue reading OSPF Type2 Message / DBD Packet (Database Descriptor)