350-401 exam dumps: questions 401 to 500 of 629

Correct answer: A

• A. Correct.

  This is the correct answer. For a route to qualify as a feasible successor, its reported distance must be less than the feasible distance of the current successor route. If this condition is not met, there will be no feasible successor.

• B. Incorrect.

  While a route stuck in active indicates an issue, it’s not relevant to the lack of a feasible successor. Stuck in active occurs when a query for an alternate route fails to find a response within the allowed time.

• C. Incorrect.

  The removal of the successor route would lead to the route becoming invalid, but it does not directly explain why there is no feasible successor.

• D. Incorrect.

  If the feasible condition is satisfied, the route would be installed as a feasible successor. This statement is incorrect and contradicts the premise of the question.

Correct answer: B

• A. Incorrect.

  This option refers to a stub area, which reduces the size of the OSPF database by blocking external LSAs (Type 5). However, it still allows inter-area routes (Type 3 LSAs), which is not ideal for a branch office with limited connectivity.

• B. Correct.

  A totally stubby area blocks both external (Type 5) and inter-area (Type 3) LSAs, injecting only a default route into the area. This is the best choice for a branch office requiring minimal routing information.

• C. Incorrect.

  An NSSA allows external routes (Type 7 LSAs) to be advertised from the branch office into the OSPF domain. This is unnecessary and inefficient for the given scenario, as the branch office only needs a default route.

• D. Incorrect.

  OSPF area range summarization is used for summarizing routes between areas, which is not relevant in this case as the branch office does not need detailed inter-area or external route information.

Correct answer: B

• A. Incorrect.

  A stub area can reduce routing overhead by blocking external routes, but it still allows inter-area routes, which might not be necessary for this scenario.

• B. Correct.

  A totally stubby area is the most optimized type for this scenario because it blocks both external and inter-area routes, requiring only a default route to the central data center, reducing resource usage significantly.

• C. Incorrect.

  An NSSA is used when the area needs to import external routes while limiting some OSPF overhead, but it is unnecessary in this scenario since the branch office does not need external routes.

• D. Incorrect.

  The backbone area is the core of an OSPF network and is not intended to reduce routing overhead. It would not optimize resource usage for a branch office.

Correct answer: A

• A. Correct.

  Correct. In a stub area, the ABR must inject a default route (Type 3 LSA) for devices in the stub area to reach external destinations. Without this default route, the devices in the stub area cannot route traffic outside the OSPF domain.

• B. Incorrect.

  Incorrect. The 'no-summary' option is used to create a totally stubby area, which blocks all summary LSAs in addition to external LSAs. However, this is unrelated to the lack of a default route injection in a standard stub area.

• C. Incorrect.

  Incorrect. A totally stubby area blocks both summary and external LSAs, but this configuration does not directly explain the lack of reachability in a standard stub area.

• D. Incorrect.

  Incorrect. Stub areas allow Type 3 summary LSAs; they block only Type 4 and Type 5 LSAs (external routes). Therefore, this explanation is not valid for the scenario.

Correct answer: B

• A. Incorrect.

  Configuring the branch office router as an OSPF stub area reduces the routing table size by blocking external Type 5 LSAs but still allows Type 3 summary LSAs. However, this does not completely minimize the routing table, as summary routes will still be present.

• B. Correct.

  Configuring the branch office router as an OSPF totally stubby area eliminates both external Type 5 LSAs and Type 3 summary LSAs, minimizing the routing table to only include a default route to the area border router (ABR). This is the most efficient configuration for limited connectivity needs.

• C. Incorrect.

  Configuring the branch office router as a not-so-stubby area (NSSA) is useful for injecting external routes into OSPF, but it does not minimize the routing table size for the branch office.

• D. Incorrect.

  Disabling OSPF and using static routes might reduce complexity, but it eliminates the dynamic routing benefits of OSPF and is not the recommended solution in this scenario.