[计算机类试卷]思科认证640-802模拟试卷7及答案与解析.doc

1、思科认证 640-802模拟试卷 7及答案与解析 1 During the boot sequence, a Ezonexam 2800 series router needs to locate and load an operating system. What is the default order the router uses to find an operating system? （ A） ROM, TFTP server, Flash （ B） Flash, TFTP server, ROM （ C） Flash, NVRAM, TFTP server （ D） Flash,

2、 ROM, TFTP server （ E） Flash, TFTP server, RAM 2 Study the Exhibit below carefully: London#show vtp VTP Version: 2 Configuration Revision: 0 Maximum VLANs supported locally: 64 Number of existing VLANs: 5 VTP Operating Mode: Client VTP Domain Name: London VTP Pruning Mode: Disabled VTP V2 Mode: Disa

3、bled VTP Traps Generation: Disabled Based on the information given above, what is the VTP function of this particular switch? （ A） Learn and save VTP configuration in the running configuration. （ B） Create and change VLANs. （ C） Forwards information about VTP configuration. （ D） VTP is disabled on t

4、his device. （ E） VTP is not saved to NVRAM. 3 Which one of the following characteristics is true regarding the use of hubs and switches? （ A） Hubs can have their ports be configured with VLANs （ B） Using hubs is costly with regard to bandwidth availability. （ C） Switches can not forward broadcasts.

5、（ D） Switches are more efficient than hubs in processing frames. （ E） Switches increase the number of collision domains in the network. 4 You have a class C network, and you need to design it for 5 usable subnets with each subnet handling a minimum of 18 hosts each. Which of the following network ma

6、sks should you use? （ A） 225.225.224.0. （ B） 225.225.240.0. （ C） 225.225.255.0. （ D） 255.255.255.224 （ E） 225.225.255.240 5 A Ezonexam Ethernet switch receives a unicast frame with a destination MAC that is listed in the switch table. What will this switch do with the frame? A. The switch will forwa

7、rd the frame to a specific port B. The switch will forward the frame to all ports except the port on which it was received C. The switch will return a copy of the frame out the source port D. The switch will not forward unicast frames E. The switch will remove the destination MAC from the switch tab

8、le F. None of the above. 6 Which protocol automates all of the following functions for hosts on a network: IP configuration, IP addresses, subnet masks, default gateways, and DNS server information? A. CDP B. SNMP C. DHCP D. ARP E. DNS F. None of the above 7 What is the subnet for the host IP addres

9、s 201.100.5.68/28? A. 201.100.5.0 B. 201.100.5.32 C. 201.100.5.64 D. 201.100.5.65 E. 201.100.5.31 F. 201.100.5.1 8 What is the IEEE standard associated with Gigabit Ethernet? (Select two answer choices) A. 802.11 B. 802.5 C. 802.3ab D. 802.3ae E. 802.3z F. 802.3u 9 A new switch is being installed in

10、 the Ezonexam network and you have been assigned the task of connecting it to an existing switch. In doing this, you want to set up the VLAN Trunking Protocol so that VLAN information can be passed between the switches. Which of the following must you do to accomplish this? (Choose all that apply).

11、（ A） You must set each end of the trunk line to IEEE 802.1e encapsulation. （ B） You must set the same VTP management domain name on both switches. （ C） You must set all ports on the two switches as access ports. （ D） You must configure one of the switches as a VTP server. （ E） You must use a rollove

12、r cable to connect the two switches. 10 Which of the following commands would be applied to a WAN interface, but not on LAN Interface? (Choose all that apply) A. IP address B. encapsulation PPP C. no shutdown D. authentication CHAP E. Speed F. None of the above 思科认证 640-802模拟试卷 7答案与 解析 1 【正确答案】 B 【试

13、题解析】 Explanation: Booting up the Router: Cisco routers can boot Cisco IOS software from these locations: 1. Flash memory 2. TFTP server 3. ROM (not full Cisco IOS) Multiple source options provide flexibility and fallback alternatives. 2 【正确答案】 C 【试题解析】 Explanation: From the output this switch is ope

14、rating merely as VTP client, so it basically does as the VTP server says, and passes on information about VTP configuration to the next switch in line. Incorrect Answers: A. This is incorrect because the function is redundant. B. This incorrect because the switch must be in server or transparent mod

15、e to create and change VLANs. D. This is incorrect because if VTP would be disabled, it wouldnt appear on the command output. E. If this were true, the VTP configuration information would not be displayed after being powered on. 3 【正确答案】 E 【试题解析】 Explanation: Switches increases the number of collisi

16、ons domains in the network. Switches that are configured with VLANs will reduce the size of the collision domains by increasing the number of collision domains in a network, but making them smaller than that of one big, flat network. Incorrect Answers: A. Switches are capable of VLAN configurations,

17、 but hubs are not. B. Hubs are generally the least costly method possible to connect multiple devices together in a network. C. Switches forward broadcasts and multicasts, by default, to all ports within the same VLAN. Only routers block all broadcast traffic by default. D. Switches and hubs can be

18、equally efficient in processing frames, in theory. In practice, switches are generally more efficient as they usually have more CPU and memory allocated to them, and are generally much more expensive than a simple hub. 4 【正确答案】 D 【试题解析】 Explanation: The default subnet mask for class C network is 255

19、.255.255.0. If one has to create 5 subnets, then 3 bits are required. With 3 bits we can create 8 subnets. The remaining 5 bits are used for Hosts. One can create 30 hosts using 5 bits in host field. This matches with the requirement. Incorrect Answers: A, B: This is an illegal subnet mask for a cla

20、ss C network, as the third octet can not be divided when using a class C network. C: This is the default subnet mask for a class C network. It provides for one network, with 254 usable host IP addresses. E: This subnet mask will provide for 14 separate networks with 14 hosts each. This does not meet

21、 the requirement of a minimum of 18 hosts. 5 【正确答案】 A 【试题解析】 Explanation:How Does the Switch Find Host MACs?Lets use the diagram below to help us understand how address learning process takes place. Lets assume that we have just powered on the switch. It has nothing in its MAC table. We connect the

22、cables from the hosts on the switch interfaces as shown in the diagram. Host A initiates a connection towards Host D, and the following takes place:1. Host A (interface fe0/0) sends a frame to Host D (MAC address:0000.43c5.334c).2. The switch inspects the Source Address in the frame and notes in its

23、 table the MAC address of Host A along with the Interface number from which the frame originated.3. The switch inspects the Destination Address in the frame. Since it does not have Hosts D MAC address in its table, it constructs a broadcast frame and forwards out all interfaces except the interface

24、from where the original frame arrived.4. Host D identifies itself as the expected recipient and responds back to Host A. The switch receives the respond frame on interface fe0/11 and places the SA in its table along with the interface number where the frame came from.5. From now on, further communic

25、ation between the two hosts will be switched to the appropriate interfaces based on the MAC tables entries.This process takes place every time a new host is attached on the switch and initiates traffic. The switch tries to keep its MAC table up-to-date, therefore if some hosts do not initiate traffi

26、c for a certain amount of time, the switch removes them from its table and reinserts them when they begin sending traffic. 6 【正确答案】 C 【试题 解析】 Explanation: DHCP uses the concept of the client making a request and the server supplying the IP address to the client, plus other information such as the de

27、fault gateway, subnet mask, DNS IP address, and other information. Incorrect Answers: A. CDP is the Cisco Discovery Protocol. It is used by Cisco devices at the data link layer to obtain information about their directly connected neighbors. B. SNMP is the Simple Network Management Protocol. This is

28、used for the maintenance, management, and monitoring of network devices. D. ARP is the Address Resolution Protocol, which is used to resolve layer 2 MAC addresses to layer 3 IP addresses. E. DNS is the Domain Name Service. It is used to resolve domain names (for example, ) to IP addresses. The IP ad

29、dress location of primary and secondary DNS resolver servers can be obtained for hosts using DHCP. 7 【正确答案】 C 【试题解析】 Explanation: This question is much easier then it appears when you convert it to binary and do the Boolean operation as shown below: IP address 201.100.5.68 = 11001001.01100100.000001

30、01.01000100 /28 mask = 11111111.11111111.11111111.11000000 AND result = 11001001.01100100.00000101.01000000 AND in decimal= 200. 100. 5. 64 8 【正确答案】 C,E 【试题解析】 Explanation: The IEEE 802.3z standard describes 1000BASE-SX. The 1000BaseT standard was released in June 1999, defined by IEEE 802.3ab. Inco

31、rrect Answers: A. This describes the standard used for wireless networks. B. This is the standard for token ring networks. D. On June 17, 2002 the IEEE 802.3ae specification for 10 Gigabit Ethernet was approved as an IEEE standard by the IEEE Standards Association (IEEE-SA) Standards Board. F. IEEE

32、802.3u describes the standard for 100BASE-TX. 9 【正确答案】 B,D 【试题解析】 Explanation:The following describes what is needed in order to correctly set up VTP:Incorrect Answers:A. The encapsulation can be either ISL or 802.1Q, and need to match at each end of the trunk.C. Ports must only be assigned to VLANS

33、. Once that is done and the trunk is up and running, the VLAN information will be passed between the switches.E. A regular CAT5 cable is used to connect the switches, assuming 10/100 Ethernet is used. 10 【正确答案】 B,D 【试题解析】 Explanation: PPP encapsulation can be used in ISDN interfaces, Asynchronous se

34、rial interfaces, and point to point serial WAN connections. PPP is not an option for LAN interfaces. CHAP authentication is a PPP 3 way authentication method. CHAP authentication can only be used on PPP encapsulated interfaces and is not a LAN interface configuration option. Incorrect Answers: A, C. This command can be applied to both LAN and WAN interface types. E. The speed command is used on LAN interfaces, and is not used on WAN interface types.