2021思科认证模拟试题7节

发布时间:2021-12-10
2021思科认证模拟试题7节

2021思科认证模拟试题7节 第1节


要在交换机上运行802.1w,可使用哪个命令来启用该协议?()

A.Switch(config)#spanning-tree mode rapid-pvst

B.Switch#spanning-tree mode rapid-pvst

C.Switch(config)#spanning-tree mode 802.1w

D.Switch#spanning-tree mode 802.1w

答案:A


以下子网掩码最适合点到点链路的是()

A.255.255.255.224

B.255.255.255.248

C.255.255.255.240

D.255.255.255.252

正确答案:D


You are given a PC, a router, and a cable. Select the correct combination that will allow you to log into router VE1 locally using a terminal emulation program such as HyperTerminal.

A. Connect the PC's COM port to the router's console port using a straight-through cable.

B. Connect the PC's COM port to the router's console port using a rollover cable.

C. Connect the PC's COM port to the router's Ethernet port using a straight-through cable.

D. Connect the PC's Ethernet port to the router's Ethernet port using a rollover cable.

E. Connect the PC's Ethernet port to the router's Ethernet port using a straight- through cable.

F. None of the above

正确答案:B
B 解析:Explanation:
To connect the Router in Console port to configure using HyperTerminal, you required the Rollover Cable, which connects the PC's COM port to the router's Console port.

Incorrect Answers:
A, C, E: Straight Cables are used for: Host to switch, Switch to Router.

D: Rollover cables are used for Console/COM connections, not for IP traffic over the
Ethernet ports.


IP地址11001101111101111000001100001111的点分十进制为()

A.205.247.131.15

B.205.237.131.15

C.205.247.151.15

D.205.247.31.15

正确答案:A


At which OSI layer is a logical path created between two host systems named VE1 and VE2 on the Ezonexam LAN?

A. Physical

B. Session

C. Data link

D. Transport

E. Network

F. Application

G. Presentation

正确答案:E
E


查看路由表的命令是:()

A.show interface

B.show run

C.show ip route

D.show table

正确答案:C


2021思科认证模拟试题7节 第2节


请参见下图。可为图中所示的主机分配哪两个IP地址()

A.192.168.65.31

B.192.168.65.32

C.192.168.65.35

D.192.168.65.60

E.192.168.65.63

F.192.168.65.64

正确答案:CD


What is the subnet for the host IP address 172.16.210.0/22?

A. 172.16.42.0

B. 172.16.107.0

C. 172.16.208.0

D. 172.16.252.0

E. 172.16.254.0

F. None of the above

正确答案:C
C 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 172.16.210.0 = 10101100.00010000.11010010.00000000
/22 mask = 11111111.11111111.11111100.00000000
AND result = 11111111.11111111.11010000.00000000
AND in decimal= 172. 16. 208. 0


With regard to Ethernet media access methods, which of the following are true?

(Choose all that apply.)

A.A device waits for an electronic signal before transmitting.

B.A device listens and waits until the media is not busy before transmitting.

C.All devices on an Ethernet segment see data that passes on the network medium.

D.Only the sender and the receiver devices see data that passes on the network medium.

E.Ethernet networks allow you to configured devises with higher transmission priority.

正确答案:BC
解析:Explanation:
Ethernet uses the CSMA/CD access method.
CSMA/CD logic helps prevent collisions and also defines how to act when a collision does occur. The CSMA/CD algorithm words like this:
1. A device with a frame. to send listens until the Ethernet is not busy.
2. When the Ethernet is not busy, the sender begins sending the frame.
3. The sender listens to make sure that no collision occurred.
4. Once the senders hear the collision, they each send a jamming signal, to ensure that all stations recognize the collision.
5. After the jamming is complete, each sender randomizes a timer and waits that long.
6 When each timer expires, the process starts over with Step 1.
So, all devices on the Ethernet need to use CSMA/CD to avoid collisions and to recover when inadvertent collisions occur.


网络中经常使用“帧中继”服务,请选出帧中继的优点()

A.偷占带宽

B.提供拥塞管理机制

C.可以使用任意广域网协议

D.灵活的接入方式

正确答案:ABD


某台PC,能ping通路由器,但不能telnet到路由器,可能的原因是()

A.PC的IP地址设置错误

B.路由器端口IP设置错误

C.路由器端口处于关闭状态

D.telnet密码未设置

正确答案:D


What is the purpose of the Spanning Tree Protocol (STP)?

A.To prevent routing loops

B.To create a default route

C.To provide multiple gateways for hosts

D.To maintain a loop-free Layer 2 network topology

E.To enhance the functions of SNMP

正确答案:D
解析:Explanation:
STP's main task is to stop network loops from occurring on your Layer 2 network (bridges or switches). It vigilantly monitors the network to find all links, making sure that no loops occur by shutting down any redundant ones. STP uses the spanning-tree algorithm (STA) to first create a topology database, then search out and destroy redundant links. With STP running, frames will only be forwarded on the premium, STP-picked links.


2021思科认证模拟试题7节 第3节


While troubleshooting a network connectivity problem, a Ezonexam technician observes steady link lights on both the workstation NIC and the switch port to which the workstation is connected. However, when the ping command is issued from the workstation, the output message "Request timed out." is displayed. At which layer of the 7-layer OSI model does the problem most likely exist?

A. The data link layer

B. The application layer

C. The protocol layer

D. The access layer

E. The session layer

F. The network layer

G. None of the above

正确答案:F
F


“ipaccess-group”命令在接口上缺省的应用方向是什么"()。

A.in

B.具体取决于接口应用哪个访问控制列表

C.out

D.无缺省值

正确答案:C


以下不属于动态路由协议的是()

A.RIP

B.ICMP

C.IS-IS

D.OSPf

正确答案:B


请参见图示。主机A无法访问Internet。此问题的原因是什么

A.主机A的IP地址不正确

B.主机A的默认网关不正确

C.两台路由器的Fa0/1接口配置了不同的子网

D.R1Fa0/0的子网掩码不正确

正确答案:C


You have a network that supports VLSM and you need to reduce IP address waste in your point to point WAN links. Which of the masks below would you use?

A. /38

B. /30

C. /27

D. /23

E. /18

F. /32

正确答案:B
B 解析:Explanation:
For a single point to point link, only 2 IP addresses are required, one for the serial interface of the router at each end. Therefore, the 255.255.255.252 subnet mask is often used for these types of links because no IP addresses are wasted. The subnet mask 255.255.255.252 is a /30, so answer B is correct.

Incorrect Answers:
A. The largest mask that can be used is the single IP host mask, which is /32. It is not possible to use a /38 mask, unless of course IPv6 is being used.

C, D, E. These masks will provide for a larger number of host addresses, and since only 2 IP addresses are needed for a point to point link, these extra addresses are wasted.

F: No available host addresses with a /32 mask


哪个命令使路由器进入路由配置模式()

A.router rip

B.Ctrl+Z

C.interfaces0/0

D.network 201.203.5.0

正确答案:A


2021思科认证模拟试题7节 第4节


能够分配给设备的IP,应该是()

A.网络有效IP

B.网络号

C.网络广播地址

D.任意IP

正确答案:A


路由器的配置文件startup-config存放在()里

A.RAM

B.ROM

C.FLASH

D.NVRAM

正确答案:D


OSPF在建立邻接关系的过程中使用了哪几类报文()

A.HELLO报文

B.DBD(数据库描述)报文

C.LSR(链路状态请求)报文

D.LSU(链路状态更新)报文

正确答案:ABCD


PPP验证可选的验证方式有()。

A.MD5

B.PAP

C.CHAP

D.IPSec

正确答案:BC


下面是你在一台交换机上执行命令show spanning-tree时得到的输出:请问下面哪两种有关这台交换机的说法是正确的?()

A.这台交换机是根网桥

B.这台交换机不是根网桥

C.根网桥与这台交换机之间有4台交换机

D.这台交换机运行的是802.1w

E.这台交换机运行的是STP PVST+

答案:BD


Which of the following are true of Ethernet technology?

A.Hosts use a logical ring topology.

B.Hosts use a logical bus topology

C.Hosts must wait for an electronic signal to transfer data.

D.Hosts are directly connected to a wiring concentrator called a MSAU.

E.None of the above

正确答案:B
解析:Explanation:LANtopologiesdefinethemannerinwhichnetworkdevicesareorganized.FourcommonLANtopologiesexist:bus,ring,star,andtree.Thesetopologiesarelogicalarchitectures,buttheactualdevicesneednotbephysicallyorganizedintheseconfigurations.Logicalbusandringtopologies,forexample,arecommonlyorganizedphysicallyasastar.AbustopologyisalinearLANarchitectureinwhichtransmissionsfromnetworkstationspropagatethelengthofthemediumandarereceivedbyallotherstations.OfthethreemostwidelyusedLANimplementations,Ethernet/IEEE802.3networks,including100BaseT,implementabustopology,whichisillustratedinFigure2-3.Somenetworksimplementalocalbustopology.


2021思科认证模拟试题7节 第5节


The network administrator has configured port security on a Ezonexam switch. Why would a network administrator configure port security on this Ezonexam device?

A.To prevent unauthorized hosts from getting access to the LAN

B.To limit the number of Layer 2 broadcasts on a particular switch port

C.To prevent unauthorized Telnet or SSH access to a switch port

D.To prevent the IP and MAC address of the switch and associated ports

E.None of the above

正确答案:A
解析:Explanation:
You can use the port security feature to restrict input to an interface by limiting and identifying MAC addresses of the stations allowed to access the port. When you assign secure MAC addresses to a secure port, the port does not forward packets with source addresses outside the group of defined addresses. If you limit the number of secure MAC addresses to one and assign a single secure MAC address, the workstation attached to that port is assured the full bandwidth of the port.

If a port is configured as a secure port and the maximum number of secure MAC addresses is reached, when the MAC address of a station attempting to access the port is different from any of the identified secure MAC addresses, a security violation occurs. Also, if a station with a secure MAC address configured or learned on one secure port attempts to access another secure port, a violation is flagged.


100baseT的速率是()Mbit/s

A.1

B.10

C.100

D.1000

正确答案:C


下列关于路由器和交换机的描述中,错误的是()

A.路由器可以用来连接internet

B.二层交换机可以用来实现“异地网络”互连

C.路由器可以用来做路径选择

D.交换机可以转发广播

正确答案:D


都是NAT的地址转换方式()。

A.静态地址转换

B.动态地址转换

C.复用动态地址

D.端口地址转换

正确答案:ABD


What are two characteristics of "store and forward" switching? (Select two answer choices)

A.Latency fluctuates regardless of frame. size.

B.The switch receives the complete frame. before beginning to forward it.

C.Latency through the switch varies with frame. length.

D.The switch checks the destination address upon receipt of headers.

正确答案:BC
解析:Explanation:
With store-and-forward, the entire frame. is received by the switch before the first bit of the frame. is forwarded. As soon as the incoming switch port receives enough of the frame. to see the destination MAC address, the forwarding decision is made and the frame. is transmitted out the appropriate outgoing port to the destination device. So, each frame. might experience slightly less latency. Store and forward switching may add latency when compared to other switching methods such as cut through, but it can reduce the amount of errors that become forwarded through a network.

Incorrect Answers:
A. The amount of latency that is introduced with this method of switching is dependent on the size of the frame, as the switch must wait to receive the entire frame. before sending it.

D. The switch must wait for the entire frame. before forwarding it on, and not just the headers.


配置路由器特权用户“加密密码”的命令是:()

A.password

B.enable password

C.enable secret

D.passwd

正确答案:C


2021思科认证模拟试题7节 第6节


You want to upgrade the Ezonexam LAN so that all ports operate in full duplex mode. Which statement is true about full-duplex Ethernet when comparing to half-duplex Ethernet?

A.Full-duplex Ethernet consists of a shared cable segment. Half-duplex provides a point-to-point link

B.Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receive

C.Full-duplex Ethernet can provide higher throughput than can half-duplex Ethernet of the same bandwidth

D.Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex Ethernet uses a jam signal

E.None of the above

正确答案:C


下列选项中不属于数据链路层的广域网通信协议的是()。

A.HDLC

B.PPP

C.ICMP

D.Frame-Relay

正确答案:C


What kind of cable should be used to establish a trunked line between two Catalyst switches?

A.A straight-through cable

B.An EIA/TIA-232 serial cable

C.An auxiliary cable

D.A modem cable

E.A cross-over cable

正确答案:E
解析:Explanation: A crossover cable is used to connect two of the same device types, or devices from the same OSI layer.


下列对RIP的配置中,合法的命令是()

A.router rip 100 network 10.12.0.0

B.router rip 100 network 10.0.0.0

C.router rip network 10.12.0.0

D.router rip 100 network 10.0.0.0

正确答案:C


通配符掩码和子网掩码之间的关系是()。

A.两者没有什么区别

B.通配符掩码和子网掩码恰好相反

C.一个是十进制的,另一个是十六进制的

D.两者都是自动生成的

正确答案:A


在使用链路状态路由的网络中,由网络变更触发的更新可以加速收敛过程。

此题为判断题(对,错)。

正确答案:√


2021思科认证模拟试题7节 第7节


IP地址为:192.168.50.70,掩码为:255.255.255.248,则该IP和掩码结合,共划分了多少个子网(不包括全0子网和全1子网)()

A.8

B.30

C.6

D.14

正确答案:B


当外发接口不可用时,路由表中的静态路由条目中该路由将保持在路由表中,因为它是静态路由。

此题为判断题(对,错)。

正确答案:×


通过路由器的“配置端口console”对路由器进行配置,应该使用的线缆为()

A.交叉线缆

B.直通线缆

C.反转线缆

D.任意线缆

正确答案:C


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 masks 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

正确答案:D
解析:Explanation:ThedefaultsubnetmaskforclassCnetworkis255.255.255.0.Ifonehastocreate5subnets,then3bitsarerequired.With3bitswecancreate8subnets.Theremaining5bitsareusedforHosts.Onecancreate30hostsusing5bitsinhostfield.Thismatcheswiththerequirement.IncorrectAnswers:A,B:ThisisanillegalsubnetmaskforaclassCnetwork,asthethirdoctetcannotbedividedwhenusingaclassCnetwork.C:ThisisthedefaultsubnetmaskforaclassCnetwork.Itprovidesforonenetwork,with254usablehostIPaddresses.E:Thissubnetmaskwillprovidefor14separatenetworkswith14hostseach.Thisdoesnotmeettherequirementofaminimumof18hosts.


Regarding DHCP (dynamic host configuration protocol), which two of the following choices below are true? (Select two answer choices)

A. The DHCP Discover message uses FF-FF-FF-FF-FF as the Layer 2 destination address.

B. The DHCP Discover message uses UDP as the transport layer protocol.

C. The DHCP Discover message uses a special Layer 2 multicast address as the destination address.

D. The DHCP Discover message uses TCP as the transport layer protocol.

E. The DHCP Discover message does not use a Layer 2 destination address.

F. The DHCP Discover message does not require a transport layer protocol.

正确答案:AB
A,B 解析:Explanation:
DHCP uses UDP as its transport protocol. DHCP messages from a client to a server are sent to the DHCP server port (UDP port 67), and DHCP messages from a server to a client are sent to the DHCP client port (UDP port 68).The client broadcasts a DHCPDISCOVER message on its local physical subnet. The DHCPDISCOVER message may include options that suggest values for the network address and lease duration. BOOTP relay agents may pass the message on to DHCP servers not on the same physical subnet.

Each server may respond with a DHCPOFFER message that includes an available network address in the "ipaddr" field (and other configuration parameters in DHCP options). Servers need not reserve the offered network address, although the protocol will work more efficiently if the server avoids allocating the offered network address to another client. The server unicasts the DHCPOFFER message to the client (using the DHCP/BOOTP relay agent if necessary) if possible, or may broadcast the message to a broadcast address (preferably 255.255.255.255) on the client's subnet.

Incorrect Answers:
C. DHCP messages are broadcast to the "all hosts" address. IP multicast addresses are not used.

D. UDP is used, not TCP.

E. Since DHCP is used so that a client can obtain an IP address, a layer two destination address must be used, as the layer 3 IP address does not yet exist on the client for the return traffic.

F. DHCP, along with nearly every other type of traffic, requires the use of a transport layer protocol.


OSPF完全Stub区域不存在()LSA。

A.一类

B.二类

C.三类

D.四类

E.五类

正确答案:CDE