Refer to the exhibit. You have completed an OSPF implementation, and you are verifying OSPF operation. You notice that router A and router B are stuck in the two-way state. From the show ip ospf interface command output, what is the cause of this issue?
 

A. All OSPF implementations must have at least one interface in area 0.

B. You are attempting to run in the broadcast mode over an NBMA interface.

C. Both routers are configured to function as a BDR; therefore, there is no DR router.

D. Someone has changed the OSPF router ID; therefore you must clear the OSPF process.

E. The OSPF priority is set to 0 on both routers; therefore neither can become the DR.






 

Suggested Answer: E

Explanation -
When OSPF adjacency is formed, a router goes through several state changes before it becomes fully adjacent with its neighbor. The states are Down, Attempt,
Init, 2-Way, Exstart, Exchange, Loading, and Full.
An OSPF neighbor reaches the 2-way state when bidirectional communication is established (each router has seen the other`s hello packet). This is the beginning of an OSPF adjacency. On broadcast media and non-broadcast multiaccess networks, the DR and BDR are elected in this state. But the priority on both routers are 0 so no DR and BDR are elected -> These routers stay in the 2-way state.
(Reference and a good resource of OSPF Neighbor states:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0e.shtml)

This question is in 300-101 Cisco Implementing Cisco IP Routing (ROUTE) Exam
For getting Cisco Certified Network Professional (CCNP) Routing and Switching Certificate




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