ActualTests.Cisco.640-802.Exam.Q.and.A.08.15.08-DDU (1130589), страница 39
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This would be the result of a /27 network mask.QUESTION 323:You have a class B network with a 255.255.255.0 mask. Which of the statementsbelow are true of this network? (Select all valid answers)A. There are 254 usable subnets.B. There are 256 usable hosts per subnet.C. There are 50 usable subnets.D. There are 254 usable hosts per subnet.E. There are 24 usable hosts per subnet.F. There is one usable network.Actualtests.com - The Power of Knowing640-802Answer: A, DExplanation:The default subnet mask for Class B is 255.255.0.0. Thus an extra 8 bits have been usedfor the network portion, leaving 8 for hosts. The 2n - 2 formula (28 - 2 in this case forboth the network and IP hosts) gives us 254 networks and 254 hosts per network.Incorrect Answers:B.
We must remember to always subtract 2 (one for the network, and one for thebroadcast) so the result is 254, not 256.C, E: No possible network mask would give us this exact number of subnets or hosts.F. This would be true if this were a class C network, not a class B.QUESTION 324:How many usable IP addresses can you get from a conventional Class C address?A. 128B. 192C. 254D. 256E. 510Answer: CExplanation:Class Caddresses range from 192.0.0.0 through 223.225.225.225 and default subnetmaskof 255.255.255.0.
In Class C addresses, the first 24 bits are used as for the networkIDwhile only the last 8 bits is used for the host ID. Using the 2n-2 formula, we cancalculate that Class C addresses can support a maximum of 254 (28-2) hosts.Incorrect Answers:D. Note that the question asked for the number of usable addresses, and not the totalnumber of all addresses. We must subtract 2 for the network and broadcast addresses tocalculate the number of usable addresses in any subnet.QUESTION 325:Your ISP assigned you a full class B address space. From this, you need at least 300sub-networks that can support at least 50 hosts each. Which of the subnet masksbelow are capable of satisfying your needs? (Select two).A.
255.255.255.0B. 255.255.255.128C. 255.255.252.0D. 255.255.255.224Actualtests.com - The Power of Knowing640-802E. 255.255.255.192F. 255.255.248.0Answer: B, EExplanation:Requirement in the question is that the company needs 300 subnets and 50 hosts persubnet.Number of Bits in the Host orSubnet FieldMaximum number of Hosts orSubnets (2n-2)1022364145306627126825495101010221120461240941381901416,382With 9 bits used for the subnet portion, we get 510 subnets and using the remaining 7 bitsfor the hosts gives us 126 hosts per subnet.
The subnet mask will be 255.255.255.128With 10 bits used for the subnet portion, we get 1022 subnets and then using theActualtests.com - The Power of Knowing640-802remaining 6 bits for hosts provides 62 hosts per subnet. The subnet mask will be255.255.255.192 in this case which will also fulfill the requirement.QUESTION 326:A Certkiller PC has the IP address 172.16.209.10 /22.
What is the subnet of thisaddress?A. 172.16.42.0B. 172.16.107.0C. 172.16.208.0D. 172.16.252.0E. 172.16.254.0Answer: CExplanation:172.16.209.10/22 translates to 10101100.00010000.11010001.00001010 in binary form.The network portion is 22 bits, so after the logical AND comparison the network addresstranslates to10101100.00010000.110100001.00001010. Converting the network portionto decimal results in the address 172.16.208.0/22QUESTION 327:You've been assigned the CIDR (classless inter domain routing) block of115.64.4.0/22 from your ISP. Which of the IP addresses below can you use for ahost? (Select all valid answers)A.
115.64.8.32B. 115.64.7.64C. 115.64.6.255D. 115.64.3.255E. 115.64.5.128F. 115.64.12.128Answer: B, C, EExplanation:115.64.4.0 = 01110011.01000000.00000100.00000000Subnet mask = 11111111.11111111.11111100.00000000= 255.255.252.0Subnet number = 01110011.01000000.00000100.00000000= 115.64.4.0Broadcast = 01110011.01000000.00000111.11111111= 115.64.7.255Valid address range = 115.64.4.1 - 115.64.7.254Actualtests.com - The Power of Knowing640-802QUESTION 328:A Certkiller remote office branch is set up as shown in the diagram below:All of the hosts in the above exhibit are connected with each other via the singleCatalyst switch.
Which of the following statements correctly describe the addressingscheme of this network? (Select three)A. The subnet mask in use is 255.255.255.192.B. The subnet mask in use is 255.255.255.128.C. The IP address 172.16.1.25 can be assigned to hosts in VLAN1.D. The IP address 172.16.1.205 can be assigned to hosts in VLAN1E. The LAN interface of the router is configured with one IP address.F. The LAN interface of the router is configured with multiple IP addresses.Answer: B, C, FExplanation:Based on the diagram above, the subnet mask used for each VLAN is 255.255.255.128.This means that hosts in VLAN 1 will be addressed 172.16.1.1-172.16.1.126, with172.16.1.127 being used as the broadcast address.
Hosts in VLAN 2 will be addressed172.16.1.129-172.16.1.254. Because there is only one LAN interface on the router, subinterfaces will be used, so the router's LAN interface will be configured with 2 IPaddresses, one for VLAN 1 and 1 for VLAN 2.Incorrect Answers:A. This subnet mask will only provide 62 host IP addresses, and the diagram shows thatas many as 114 host IP addresses are needed.D. This IP address can be used in VLAN 2, not VLAN 1.E.
Since there are 2 subnets in this network, each separate network will require a distinctdefault gateway IP address, so 2 IP addresses will be required on the LAN interface ofthe router.Actualtests.com - The Power of Knowing640-802QUESTION 329:On the topic of VLSM, which one of the following statements best describes theconcept of the route aggregation?A. Deleting unusable addresses through the creation of many subnets.B. Combining routes to multiple networks into one supernet.C. Reclaiming unused space by means of changing the subnet size.D.
Calculating the available host addresses in the AS.E. None of the aboveAnswer: BExplanation:In the networking world route aggregate means combining routes to multiple networksinto one. This is also known as route summarization or supernetting. It is normally usedto reduce the number of route entries in the routing table by advertising numerous routesinto one larger route.Reference: CCNA Self-Study CCNA ICND exam certification Guide (Cisco Press,ISBN 1-58720-083-X) Page 236.QUESTION 330:In the Certkiller network shown below, what is the most efficient summarizationthat CK1 can use to advertise its networks to CK2 ?A.
172.1.4.0/24172.1.5.0/24172.1.6.0/24172.1.7.0/24B. 172.1.0.0/22C. 172.1.4.0/25172.1.4.128/25172.1.5.0/24172.1.6.0/24172.1.7.0/24D. 172.1.0.0/21E. 172.1.4.0/22Answer: EActualtests.com - The Power of Knowing640-802Explanation:Route Summarization Overview:In large internetworks, hundreds, or even thousands, of network addresses can exist. It isoften problematic for routers to maintain this volume of routes in their routing tables.Route summarization (also called route aggregation or supernetting) can reduce thenumber of routes that a router must maintain, because it is a method of representing aseries of network numbers in a single summary address.For example, in the figure above, router D can either send four routing update entries orsummarize the four addresses into a single network number.
If router D summarizes theinformation into asingle network number entry, the following things happen:1. Bandwidth is saved on the link between routers D and E.2. Router E needs to maintain only one route and therefore saves memory.3. Router E also saves CPU resources, because it evaluates packets against fewer entriesin its routing table.A summary route is announced by the summarizing router as long as at least one specificroute in its routing table matches the summary route.QUESTION 331:Part of the Certkiller network is shown below:The five Ethernet networks connected to router Certkiller 1 in the graphic have beensummarized for router Certkiller 2 as 192.1.144.0/20.
Based on this information,which of the following packet destination addresses will Certkiller 2 forward toActualtests.com - The Power of Knowing640-802Certkiller 1, according to this summary? (Choose two.)A. 192.1.1.144B. 192.1.159.2C. 192.1.138.41D. 192.1.151.254E. 192.1.160.11F. 192.1.143.145G. 0.0.0.0Answer: B, DQUESTION 332:Refer to the following exhibit:In this network segment, the IP subnets connected to router Certkiller 2 have beensummarized as a 192.18.176.0/21 route and sent to Certkiller 1. Based on thisinformation, which two packet destination addresses will Certkiller 1 forward toCertkiller 2? (Choose two)A. 192.18.183.255B. 192.18.159.2C.
192.18.194.160D. 192.18.179.4E. 192.18.183.41F. 192.18.184.45Answer: D, EActualtests.com - The Power of Knowing640-802QUESTION 333:What is the subnet address of the host with an IP address of 172.16.159.159/22?A. 172.16.128.0B. 172.16.156.0C. 172.16.159.128D. 172.16.159.0E. 172.16.192.0F. 172.16.0.0G. None of the aboveAnswer: BExplanation:In this question there are a total of 6 bits borrowed from the host portion with the subnetmask 255.255.252.0. This will leave us 64 networks with 1022 and the IP subnets foreach will be a multiple of 4. Some of the networks are as follows:/22 172.16.148.0 - 255.255.252.0 - 1022 hosts/22 172.16.152.0 - 255.255.252.0 - 1022 hosts/22 172.16.156.0 - 255.255.252.0 - 1022 hosts/22 172.16.160.0 - 255.255.252.0 - 1022 hosts/22 172.16.164.0 - 255.255.252.0 - 1022 hosts/22 172.16.168.0 - 255.255.252.0 - 1022 hosts/22 172.16.172.0 - 255.255.252.0 - 1022 hosts/22 172.16.176.0 - 255.255.252.0 - 1022 hostsQUESTION 334:Certkiller is migrating to an IPv6 addressing scheme.
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