[ospf] The state of OSPF adjacency

Init: Hey, we're getting somewhere! The first hello packet has been received from the neighbor.

2-Way: When you're here, you're almost gold. At this point, each router has received a Hello packet containing its own RID, indicating bidirectiona communication. When a router receives a hello packet containing its own RID, it's ot just talking to itself; that's the remote router's way of saying "I received that hello packet you sent me earlier."

Exstart: Following the DR/BDR election, the exchange of link state database ingo can begin! The router with the highest RID will begin the exchange and incremen the initial sequence number, which is determined during this stage.

Exchange: Database Descriptor (DBD) packets are exchanged. As you;d expect, these packerts contain a description of the link state database.

Loading: Routers now send Link State Request (LSR) packets to the almost-neighbor.

Full: Router database are synced and the adjacency has been formed