Which OSPF state indicates that the router has finished transmitting its database but is still receiving database information?
Correct Answer: A
Explanation/Reference:
In the loading state, routers send link-state request packets. During the adjacency, if a router receives an outdated or missing link-state advertisement (LSA), it requests that LSA by sending a link-state request packet.
Note: OSPF states for adjacency formation are Down, Init, Attempt, 2-way, Exstart, Exchange, Loading and Full.
Incorrect Answers:
B: After two OSPF neighboring routers establish bi-directional communication and complete DR/BDR election (on multi-access networks), the routers transition to the exstart state. In this state, the neighboring routers establish a master/slave relationship and determine the initial database descriptor (DBD) sequence number to use while exchanging DBD packets.
C: The 2-way state indicates that the router has seen its own Router ID in the Neighbor field of the neighbor's HELLO packet. Receiving a Database Descriptor (DBD) packet from a neighbor in the init state will also a cause a transition to 2-way state.
D: Once the master/slave relationship has been negotiated (the router with the highest Router-ID becomes the master), the neighboring routers transition into the exchange state. In this state, the routers exchange DBD packets, which describe their entire link-state database. The routers also send link-state request packets, which request more recent link-state advertisements (LSA) from neighbors.
References: http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13699-
29.html#anc10