| Question 1 | What designator must the OSPF backbone always use when being configured? -
A. IA -
B. Area 0 -
C. Standard -
D. Area51 |
| A1: | Answer B is correct. Area ID 0 is used to represent the backbone area. A backbone router is characterized as a router that has at least one interface connected to Area 0 (or OSPF transit area). Therefore, Area 0 is commonly referred to as the backbone area. Answer A is incorrect because IA is a designator in the routing table for an inter-area entry. Answer C is incorrect because the word "standard" is not a designator. The term is used to describe a single area environment that receives link updates, route summaries, and external route information. Answer D is incorrect because Area51 is a common theme of science fiction movies. |
| Question 2 | Which one of the following is not a valid type of OSPF router? |
| A2: | Answer D is correct. An internal router is an amalgam of various valid router types. Answer A is incorrect because an ASBR is an OSPF router that has interfaces in more than one AS. Answer B is incorrect because an ABR is an OSPF router that has interfaces in more than one area. Answer C is incorrect because a backbone router is an OSPF internal router or ABR that is a member of the internetwork backbone area. Answer E is incorrect because an internal router is an OSPF router that has all its interfaces in the same area. |
| Question 3 | Which of the following statements represent valid advantages specific to implementing a totally stubby area in your internetwork? (Choose two.) -
A. Routing table sizes can be reduced because external and summary routes are not inserted into totally stubby areas. -
B. A router always prefers an E2 route on top of an E1 route. -
C. Network traffic is reduced because the totally stubby area does not process Type 2 network link entries. -
D. Totally stubby areas typically result in lower amounts of routing information being propagated. |
| A3: | Answers A and D are correct. First of all, the routing tables will be smaller because external and summary routes are not inserted into totally stubby areas. In addition, implementing a totally stubby area results in lower amounts of routing information propagation as well as greater scalability and stability on your OSPF internetwork. Answer B is incorrect because this statement relates to the cost of an external route configured on an ASBR and is not a function of totally stubby areas. Answer C is incorrect because (although it is not necessarily an advantage) a totally stubby area DR can indeed process Type 2 network link entries. |
| Question 4 | You want to summarize routes for a certain area on an ABR in your OSPF multi-area environment. Which one of the following commands would you use? -
A. area area-id default-cost cost -
B. area area-id stub [no-summary] -
C. network address wildcard-mask area area-id -
D. area area-id range address mask |
| A4: | The correct answer is D. You instruct the ABR to perform route summarization for a specific area before injecting the routes into a different area with the area range command. Answer A is incorrect because the area area-id default-cost cost command is used to configure the cost of the default route that is being infused into a stubby area. Answer B is incorrect because the no-summary command is the process that actually creates the totally stubby area. Answer C is incorrect because this is the syntax used to designate the IP networks on the router that are a part of the OSPF network. |
| Question 5 | Which one of the following LSA types is generated by designated routers in multi-access OSPF networks to describe a collection of routers attached to a specific network? -
A. Type 1 -
B. Type 2 -
C. Type 3 -
D. Type 5 |
| A5: | Answer B is correct. Type 2 LSAs are initiated by DRs in multi-access OSPF networks and describe a group of routers attached to a specific network. They are flooded within the single area containing the network. Answer A is incorrect because Type 1 LSAs are generated by each router for its own area to describe the state of router links. Answer C is incorrect because Type 3 LSAs are initiated by ABRs and define links between ABRs and internal routers. Answer D is incorrect because Type 5 LSAs are generated by ASBRs and define routes to external (AS) destinations. |
| Question 6 | The summary-address router configuration command is used on which OSPF router types to summarize external routes to be injected into the OSPF routing domain? -
A. Area system backbone router -
B. Area border routers only -
C. Autonomous system boundary routers -
D. Internal routers |
| A6: | Answer C is correct. Although the area range command is used on ABRs to summarize internal routes, the summary-address router configuration command is implemented on an ASBR to summarize external routes that will be injected into the OSPF routing domain. You configure the ASBR to summarize external routes prior to injecting the routes into the OSPF domain. Answer A is incorrect because there is no such thing as an area system backbone router. Answer B is incorrect because the summary-address router configuration command is not used on routers that are only ABRs and are not ASBRs. Answer D is incorrect because the command is not run on internal routers. |
| Question 7 | Which one of the following is a true statement concerning area border routers? -
A. You cannot implement route summarization on an ABR, only on ASBRs. -
B. Packets are transmitted from the ABR only if an interface on the ABR is connected to a totally stubby area. -
C. Type 5 external route information will be transmitted from the ABR only if the summary is being sent to a stub area. -
D. The entire area must be synchronized before an ABR can commence the process of flooding summary link-state advertisements. |
| A7: | Answer D is correct. The entire area must be converged and synchronized before an area border router can start the process of flooding summary LSAs. Answer A is incorrect because you can indeed implement route summarization on ABRs and ASBRs. Answer B is incorrect because packets will not be transmitted from an ABR if an interface on the ABR is connected to a totally stubby area. Answer C is incorrect because Type 5 external route information will not be transmitted from the ABR interface if the summary is being sent to a stub area. |
| Question 8 | A Type 7 LSA is a special form of external route announcement that is implemented according to RFC 1587. Into what type of area is this special LSA flooded? -
A. Stub -
B. Not so stubby -
C. Totally stubby -
D. Partially stubby |
| A8: | Answer B is correct. A Type 7 LSA is a special form of external route announcement that is implemented with OSPF not-so-stubby areas. Answer A is a stub area and does not accept Type 7 LSAs. Answer C is incorrect because a totally stubby area does not accept Type 7 LSAs. Answer D is incorrect because there is no such thing as an OSPF partially stubby area. |
| Question 9 | Which of the following commands are used specifically in conjunction with configuring default routes? (Choose two.) -
A. ip route 0.0.0.0 0.0.0.0 exit-interface -
B. router ospf process-id -
C. default-information originate -
D. network address wildcard-mask area area-id |
| A9: | The correct answers are A and C. To create a default static route, you use the global configuration command ip route 0.0.0.0 0.0.0.0 exit-interface . The default-information originate command is an optional command used to propagate a Type 7 default route into the NSSA. Answer B is incorrect because the router ospf process-id command is used specifically to enable the OSPF routing process on a router. Answer D is incorrect because the command is used to designate the networks that are part of the OSPF environment. |
| Question 10 | Which one of the following commands is used exclusively to display information about a logical connection between the backbone area and a non-backbone area that is not directly connected to Area 0? -
A. show ip ospf process-id -
B. show ip ospf virtual-links -
C. show ip ospf border-routers -
D. show ip ospf database summary |
| A10: | The correct answer is B. The show ip ospf virtual-links command displays information regarding the status of any configured virtual link on a router. Answer A is incorrect because the show ip ospf process-id command exhibits information about every area to which the router is connected, as well as designates whether the router is an ABR, ASBR, or both. Answer C is incorrect because the show ip ospf border-routers command shows all of the OSPF router's internal routes to all ABRs and ASBRs in an autonomous system. Answer D is incorrect because the show ip ospf database summary command shows the router link-state summary information in the topology database. |
