<Li> 2 - Way: The 2 - Way state indicates the establishment of a bidirectional conversation between two routers . This state immediately precedes the establishment of adjacency . This is the lowest state of a router that may be considered as a Designated Router . </Li> <Li> ExStart: The ExStart state is the first step of adjacency of two routers . </Li> <Li> Exchange: In the Exchange state, a router is sending its link state database information to the adjacent neighbor . At this state, a router is able to exchange all OSPF routing protocol packets . </Li> <Li> Loading: In the Loading state, a router requests the most recent Link - state advertisements (LSAs) from its neighbor discovered in the previous state . </Li>

Advantages of open shortest path first (opsf) are