ActualTests.Cisco.640-802.Exam.Q.and.A.08.15.08-DDU (1130589), страница 58
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Single area OSPF networks do not have to be configured with the backbone area 0.Although area 1 can indeed be used, it is not required that area 1 is used. Single areaOSPF networks can be any integer from 0-4294967295.QUESTION 511:Router CK1 is running OSPF. What is the default administrative distance (AD) ofthis protocol?A. 90B. 100C. 110D. 120E.
170F. None of the aboveAnswer: CExplanation:The administrative distance values are configured on a single router and are notexchanged with other routers. Table lists the various sources of routing information,along with the default administrative distance.Default Administrative DistancesQUESTION 512:Router CK1 is running OSPF. On this router, what kind of packets does OSPF sendActualtests.com - The Power of Knowing640-802to keep up connectivity with its neighboring routers?A. SPF packetsB. hello packetsC. keepalive packetsD. dead interval packetsE.
LSU packetsF. None of the aboveAnswer: BExplanation:Hello packets simply identify the subnet, the router sending the packets and a few otherdetails. As long as a router continues to receive Hellos form existing neighbors, theattached link must still be usable, and the neighbor that sent the Hello must still be up andworking.Reference: CCNA Self-Study CCNA ICND Exam Certification Guide (Cisco Press,ISBN 1-58720-083-X) Page 192 -193Incorrect Answers:A, E. SPF (shortest path first) and LSU (link state update) packets are not used tomaintain connectivity between neighbors.C.
Keepalive packets do not exist. Hello packets perform the functions of a keepalivepacket.QUESTION 513:Part of the Certkiller OSPF network is shown below:Actualtests.com - The Power of Knowing640-802In the Certkiller network shown above, all of the routers are operational and OSPFhas converged, what will be the output from the show ip route command issued onthe Border router?A. Gateway of last resort is 10.10.10.6 of network 0.0.0.010.0.0.0/30 is subnetted, 1 subnetsC 10.10.10.4 is directly connected, Serial0/2192.168.255.0/30 is subnetted, 3 subnetsC 192.168.255.20 is directly connected, Serial0/0C 192.168.255.16 is directly connected, Serial0/1O 192.168.255.24[110/128]via 192.168.255.22, 00:12:40, Serial0/0O 192.168.2.0/24[110/138]via 192.168.255.22, 00:12:40, Serial0/0S* 0.0.0.0/0[1/0] via 10.10.10.6B. Gateway of last resort is 10.10.10.6 of network 0.0.0.010.0.0.0/30 is subnetted, 1 subnetsC 10.10.10.4 is directly connected, Serial0/2192.168.255.0/30 is subnetted, 3 subnetsC 192.168.255.20 is directly connected, Serial0/0C 192.168.255.16 is directly connected, Serial0/1O 192.168.255.24[110/128]via 192.168.255.22, 00:12:40, Serial0/1O 192.168.2.0/24[110/1572]via 192.168.255.18, 00:00:11, Serial0/0S* 0.0.0.0/0[1/0] via 10.10.10.6C.
Gateway of last resort is 10.10.10.6 of network 0.0.0.010.0.0.0/30 is subnetted, 1 subnetsC 10.10.10.4 is directly connected, Serial0/2192.168.255.0/30 is subnetted, 3 subnetsC 192.168.255.20 is directly connected, Serial0/0C 192.168.255.16 is directly connected, Serial0/1O 192.168.255.24[110/128]via 192.168.255.22, 00:12:40, Serial0/0O 192.168.2.0[110/1572]via 192.168.255.18, 00:00:11, Serial0/1S* 0.0.0.0/0[1/0] via 10.10.10.6D. Gateway of last resort is 10.10.10.6 of network 0.0.0.010.0.0.0/30 is subnetted, 1 subnetsC 10.10.10.4 is directly connected, Serial0/2192.168.255.0/20 is subnetted, 3 subnetsC 192.168.255.20 is directly connected, Serial0/0C 192.168.255.16 is directly connected, Serial0/1O 192.168.255.24[110/128]via 192.168.255.22, 00:12:40, Serial0/0O 192.168.2.0[110/1572]via 192.168.255.18, 00:00:11, Serial0/1[110/1572]via 192.168.255.22, 00:00:07, Serial0/0S* 0.0.0.0/0[1/0] via 10.10.10.6E.
None of the aboveAnswer: AActualtests.com - The Power of Knowing640-802Explanation:The key to this question lies in the cost of the route to the 192.168.2.0/24 network. WithOSPF, the cost of a link is 10,000,000/BW. Here we can see that the best path is over thetwo T1 links instead of the single 64K circuit. The OSPF cost of a link on a 1544kbps T1line is 64. Since there are two T1 links, the cost now becomes 128. Finally, when we addthe cost of the Ethernet link (10) the cost then becomes 138. Since choice A is the onlyoption with the correct cost to this network it is correct. The other answers assume thatthe single 64K link is best, which is why the cost to the 192.168.2.0/24 network shows as1572.Note: If this were a RIP network, then the best path would indeed be over the singleslower link as RIP does not consider the bandwidth of the link, only the number of hops.QUESTION 514:Please study the exhibit carefully.Based on the information shown above, which two statements are true about theloopback address that is configured on CK-B? (Choose two)A.
It indicates that CK-B should be elected the DR for the LAN.B. It provides stability for the OSPF process on CK-B.C. It ensures that data will be forwarded by CK-B.D. It decreases the metric for routes that are advertised from CK-B.E. It specifies that the router ID for CK-B should be 10.0.0.1.Answer: B, EExplanation:A loopback interface is virtual in nature, and thus will never go down as long as theActualtests.com - The Power of Knowing640-802router is powered on.
It doesn't rely on any physical network or cable to be plugged in.This makes it a prime choice for any good reference point. That brings us to the "why"about using it.When OSPF routers talk to one another, they all identify themselves. That is done by aRID, or Router ID value. An OSPF router may talk to many neighbors out multipleinterfaces, but it only has one Router ID it uses for all conversations.How does a router choose its identifier? Well, there are a couple ways. Typically, therouter chooses its highest IP address of all physical interfaces. However, if there's aloopback interface (seen as a manual intervention), the OSPF process will always use theloopback address as its RID value.In this network, stability is ensured for CK-B as it will not become the DR or the BDRbecause the other routers will have a higher router ID since the have a higher loopback IPaddress.
The DR/BDR election process is as follows:A designated router (DR) is the router elected by the network by elections. The DR iselected based on the following default criteria:* If the priority setting on a OSPF router is set to 0, that means it can NEVER become aDR or BDR.* When a DR fails and the BDR takes over, there is another election to see who becomesthe replacement BDR.* The router sending the Hello packets with the highest priority.* If two or more routers tie with the highest priority setting, the router sending the Hellowith the highest RID (Router ID) wins.* (NOTE) A RID is the highest logical (loopback) IP address configured on a router, if nological/loopback IP address is set then the Router uses the highest IP address configuredon its interfaces. (e.g.
192.168.0.1 would be higher than 10.1.1.2)* Usually the router with the second highest priority number becomes the BDR (BackupDesignated Router)* The range of priority values range from 1 - 255, with a higher value increasing itschances of becoming DR or BDR.* IF a HIGHER priority OSPF router comes online AFTER the election has taken place,it will not become DR or BDR until (at least) the DR and BDR fail.QUESTION 515:Exhibit:While troubleshooting an issue with the Certkiller OSPF network, you notice thatthere are two OSPF designated routers identified on Certkiller 4. What could explainActualtests.com - The Power of Knowing640-802this fact?A.
Two Router IDs have the same OSPF priority and are therefore tied for DR election.B. Certkiller 4 is connected to more than one multi-access network.C. The DR election is still underway and there are two contenders for the role.D. The router at 208.149.23.130 is a secondary DR in case the primary fails.E. None of the answer choices are correct.Answer: BExplanation:OSPF elects a DR and BDR for each multi-access network that the routers are connectedto. In this case, we can see that the first neighbor is the DR associated with the LANconnected to interface Ethernet1, while the last neighbor is the DR associated with theEthernet0 LAN.QUESTION 516:Network topology exhibit:Configuration exhibit (Routing Table):Actualtests.com - The Power of Knowing640-802You work as a network technician at Certkiller and you need to troubleshoot anissue with the network.Based on the information provided above, what can be determined from the routeroutput shown in the graphic?A.
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