| Explanation & Hint:
The final operational state that will form between an OSPF Designated Router (DR) and a DROTHER (a router that is neither a DR nor a BDR) once the routers reach convergence is Full.
In OSPF, “Full” is the state indicating that routers have completed the adjacency process and have full knowledge of each other’s databases. This means that they have exchanged and acknowledged all OSPF routing information, and the routers’ link-state databases are synchronized.
Here’s a brief overview of the states:
- Down: The initial state of OSPF neighbor formation. No information has been exchanged.
- Attempt: This is a state where the router has sent out OSPF Hello packets but has not received any Hello packets back from the neighbor. This state is only used in NBMA (Non-Broadcast Multi-Access) networks.
- Init: The router has received a Hello packet from its neighbor, but the receiving router’s ID was not included in the Hello packet.
- 2-Way: Bidirectional communication has been established between two routers. DR and BDR elections occur in this state.
- Exstart: DR and BDR establish a master-slave relationship and determine the sequence number for database exchange.
- Exchange: Routers send Database Description (DBD) packets to each other to exchange link-state database information.
- Loading: Routers are sending Link-State Request (LSR) and Link-State Update (LSU) packets to request and receive the actual OSPF routing information.
- Full: The routers have full knowledge of each other’s OSPF databases and are fully adjacent.
The “Established” state is not an OSPF state; it is more commonly associated with protocols like BGP (Border Gateway Protocol). |