| Question 1 | Which one of the following pairs of documents defines the Open Shortest Path First version 2 (OSPF v2) routing protocol and OSPF for Internet Protocol version 6 (IPv6), respectively? -
A. 2178 and 2740 -
B. 1058 and 2178 -
C. 2328 and 2740 -
D. 2328 and 1878 |
| A1: | Answer C is correct. RFC 2328 defines OSPF version 2 and 2740 defines OSPF for IPv6. Answer A is incorrect because RFC 2178 is an obsolete RFC for OSPF that was replaced by 2328. Answer B is incorrect because 1058 defines RIP and 2178 is obsolete. Answer D is incorrect because 1878 defines VLSM for IPv4. |
| Question 2 | Which of the following phrases best describes the OSPF exchange state? -
A. The phase in which routers have not shared information with other routers' networks -
B. The phase in which all the routers see each other in their own neighbor lists -
C. The phase in which master and slave routers can discover link-state information packets -
D. The phase in which all adjacent routers are synchronized and ready to route traffic |
| A2: | Answer C is correct. In the exchange state, OSPF master and slave routers exchange database description (DBD) packets that have LSA summary information from the master's link-state database. Answer A is incorrect because this describes the down state. Answer B is incorrect because this is the two-way state. Answer D is incorrect because this represents the full state. |
| Question 3 | Which of the following OSPF over nonbroadcast multi-access modes are Cisco-defined? (Choose all that apply.) |
| A3: | Answers B, C, and D are correct. Point-to-point, broadcast, and point-to-multipoint non-broadcast are all three Cisco-defined extensions of the RFC 2328 definition. NBMA and point-to-multipoint are both the RFC 2328-compliant modes; therefore, answers A and E are incorrect. |
| Question 4 | You want to implement OSPF in an NBMA nonbroadcast multi-access mode environment for four sites. How many subnets will you use for this topology? |
| A4: | Answer D is correct. With OSPF running in NBMA mode, all routers are in one subnet and neighbors are statically defined at the outset to get the DR election process initiated. Answers A, B, and C are incorrect because all NBMA routers use the same subnet number. |
| Question 5 | Which of the following best describes an advantage of using OSPF instead of RIPv2? (Choose two.) -
A. OSPF supports VLSM and RIPv2 cannot. -
B. OSPF can tag external routes from another AS and RIPv2 cannot. -
C. An OSPF network can grow well beyond 15 hops and RIPv2 cannot. -
D. OSPF can load balance packets across equal cost paths and RIPv2 cannot. |
| A5: | Answers B and C are correct. Answer A is incorrect because RIPv2 and OSPF both support VLSM, whereas RIPv1 does not. Answer D is incorrect because OSPF and RIP can both load balance packets across equal cost paths (four by default). In addition, OSPF is not limited by network diameter, or hop count, like RIP. |
| Question 6 | Which of the following is the proper command to execute on your Cisco router to run OSPF on all router interfaces after you have entered the router OSPF process-id command? -
A. R1(config-router)# network 255.255.255.255 0.0.0.0 area 0 -
B. R1(config-router)# network 0.0.0.0 255.255.255.255 area 0 -
C. R1(config-if)# network 0.0.0.0 255.255.255.255 area 0 -
D. R1(config-if)# network 255.255.255.255 0.0.0.0 area 0 |
| A6: | Answer B is correct. At the router configuration prompt, enter the network command where 0.0.0.0 is all networks and 255.255.255.255 is a 24-bit wildcard mask for Area 0. Answer A is incorrect because the network and mask parameters are in the wrong order. Answer C is incorrect because you are in interface configuration mode and not router configuration mode. Answer D is incorrect because the mode is wrong and the parameters are juxtaposed. |
| Question 7 | Which one of the following commands would an administrator of a Cisco router input at the IOS to facilitate full connectivity through the selection of a DR and BDR while configuring OSPF in NBMA mode? -
A. Router(config-router) neighbor 172.16.1.1 -
B. Router(config) neighbor 172.16.1.1 -
C. Router(config-router) network 172.16.1.1 -
D. Router(config) network 172.16.1.1 |
| A7: | Answer A is correct. The neighbor command can be used with an ip-address parameter to configure OSPF routers linking to nonbroadcast networks. Answer B is incorrect because it is the wrong IOS mode prompt. Answer C is incorrect because the network command is used rather than the neighbor command. Answer D is incorrect because it uses the command mode prompt and the wrong command. |
| Question 8 | Which of the following EXEC -MODE commands is used to show the contents of the OSPF topology table? |
| A8: | Answer D is correct. The show ip ospf database command displays the contents of the OSPF topological database. You can also use this command to see the router ID and OSPF process ID numbers . Answer A is incorrect because debug ip ospf adj is commonly used to monitor the DR and BDR election process. Answer B is incorrect because show ip neighbor detail is used if you need to list all the routers' neighbors. Answer C is incorrect because this displays the OSPF routing table, not the topology table. |
| Question 9 | Which of the following types of OSPF packets are valid messages used for discovering routes? (Choose two.) -
A. Hello -
B. LSP -
C. DBD -
D. ICMP |
| A9: | Answers A and C are correct. Hello packets and DBD packets are both used in the route discovery and exchange process. Answer B is incorrect because it is an acronym for link-state messages. Answer D is incorrect because it is the Internet Control Message Protocol, which functions independently of the particular routing protocol and is not used specifically for OSPF route discovery. |
| Question 10 | Which of the following IP multicast addresses is also known as the ALLSPFRouter address? -
A. 224.0.0.6 -
B. 225.0.0.4 -
C. 224.0.0.5 -
D. 226.0.0.6 |
| A10: | Answer C is correct. 224.0.0.5 is also referred to as the AllSPFRouter address. Answer A is incorrect because multicast address 224.0.0.6 goes to OSPF DRs and BDRs. Answer B is incorrect because the multicast addresses 225.0.0.0 through 231.255.255.255 are reserved according to the IANA IPv4 Multicast Guidelines set forth in RFC 3171. Answer D is incorrect because multicast network 226.0.0.0 is also reserved by the IANA. |
