思科网络学院CCNA4练习题和答案EnglishFormDEWANv4.docx

1、思科网络学院CCNA4练习题和答案EnglishFormDEWANv4思科网络学院 CCNA 4 练习题和答案 English FormD EWAN Chapter 1. WAN Switching Concepts Assessment Item:What is an advantage of packet-switched technology over circuit-switched technology?Packet-switched networks are less susceptible to jitter than circuit-switched networks are.

2、 Packet-switched networks can efficiently use multiple routes inside a service provider network. Packet-switched networks do not require an expensive permanent connection to each endpoint. Packet-switched networks usually experience lower latency than circuit-switched networks experience. Reset View

3、 Learner ResponseScoring Rule for: correctness of response 2 points for Option 2This item references content from the following areas:CCNA Exploration1.2.3 WAN Data Link Layer Concepts Assessment Item:Which statement about WAN protocols is correct?ATM differs from other WAN protocols in that it uses

4、 variably sized packets. Most WAN protocols use HDLC or a variant of HDLC as a framing mechanism. The frame header consists of the frame check sequence and cyclic redundancy check. ISDN differs from Frame Relay, HDLC, and ATM in that it is packet-switched rather than circuit-switched technology. Res

5、etScoring Rule for: correctness of response 2 points for Option 2This item references content from the following areas:CCNA Exploration1.2.4 WAN Switching Concepts Assessment Item:Why is the call setup time of a circuit-switched WAN implementation considered a drawback?Routing protocols are incompat

6、ible with this function. It restricts the communication sent to voice traffic only. A telephone must be used to initially start transferring data. Data cannot be transferred until a circuit has been established. ResetScoring Rule for: correctness of response 2 points for Option 4Assessment Item:Whic

7、h statement is true about the differences between a WAN and a LAN?WANs generally support higher bandwidth than LANs support. A WAN link typically traverses shorter geographic distances than a LAN link traverses. A WAN often relies on the services of carriers, such as telephone or cable companies, bu

8、t a LAN does not. All WAN implementations generally use the same Layer 2 protocol but there are many accepted LAN Layer 2 protocols in use. ResetScoring Rule for: correctness of response 2 points for Option 31.2.2 WAN Physical Layer Concepts Assessment Item:Which statement is true about data connect

9、ivity between a customer and a service provider?Normally the CSU/DSU is the designated demarcation point for the service provider but not the customer. The segment between the demarcation point and the central office is known as the last mile. The local loop is the segment between the CSU/DSU and th

10、e serial port on a router. Putting data on the local loop is the responsibility of the DTE. ResetScoring Rule for: correctness of response 2 points for Option 2 1.1.3 The Evolving Network Model Assessment Item:Which statement is true of the functionality of the layers in the hierarchical network mod

11、el?The purpose of the access layer is to provide very high bandwidth communications between network devices. Most security screening to prevent unauthorized entry to the network happens at the core layer. Untrusted external connections are segmented from the rest of the network at all three levels.

12、The distribution layer aggregates WAN connections at the edge of the campus. ResetScoring Rule for: correctness of response 2 points for Option 41.2.2 WAN Physical Layer Concepts Assessment Item:Which two devices are commonly used as data communications equipment? (Choose two.)modem router CSU/DSU I

13、SDN switch Ethernet switch ResetScoring Rule for: correctness of response Option 1 and Option 3 are correct.This item references content from the following areas:CCNA Exploration1.3.4 Packet Swtiched Connection Options Assessment Item:A company needs a WAN connection that is capable of transferring

14、voice, video, and data at a minimum data rate of 155 Mbps. Which WAN connection is the best choice? DSL ATM ISDN BRI ISDN PRI ResetScoring Rule for: correctness of response 2 points for Option 3 This item references content from the following areas:CCNA Exploration1.2.4 WAN Switching Concepts Assess

15、ment Item:Which switching type will allow the communication devices in the provider network to be shared and only allocated to an individual subscriber during data transfer?circuit-switched dedicated switched lines frame-switched packet-switched Reset View Learner ResponseScoring Rule for: correctne

16、ss of response 2 points for Option 4This item references content from the following areas:CCNA Exploration1.2.2 WAN Physical Layer Concepts Assessment Item:Which term describes a device that will put data on the local loop?DLCI DTE DCE BRI PRI ResetScoring Rule for: correctness of response 2 points

17、for Option 3 This item references content from the following areas:CCNA Exploration1.2.2 WAN Physical Layer Concepts Assessment Item:For digital lines, which device is used to establish the communications link between the customer equipment and the local loop?CSU/DSU Frame Relay switch ISDN switch m

18、odem PBX switch ResetScoring Rule for: correctness of response 2 points for Option 1This item references content from the following areas:CCNA Exploration1.3.3 Circuit Switched Connection Options Assessment Item:A U.S. company requires a WAN connection used only to transfer sales data from individua

19、l stores to the home office. All transfers will occur after business hours. The required bandwidth for this connection is estimated to be less than 38 kbps. Which type of connection requires the least investment for this company?ATM ISDN analog dialup T1 Leased Line ResetScoring Rule for: correctnes

20、s of response 2 points for Option 3This item references content from the following areas:CCNA Exploration1.3.5 Internet Connection Options Assessment Item:What type of connectivity is established when VPNs are used from the remote site to the private network?PVCs DLCIs tunnels virtual circuits dedic

21、ated Layer 2 links Reset View Learner ResponseScoring Rule for: correctness of response 2 points for Option 3This item references content from the following areas:CCNA Exploration1.3.5 Internet Connection Options Assessment Item:What can cause a reduction in available bandwidth on a cable broadband

22、connection?smaller cells number of subscribers committed information rate distance from the central office of the provider ResetScoring Rule for: correctness of response 2 points for Option 2This item references content from the following areas:CCNA Exploration1.3.3 Circuit Switched Connection Optio

23、ns Assessment Item:What three terms are associated with ISDN PRI? (Choose three.)DLCI circuit switching packet switching data bearer channels switched virtual circuits time-division multiplexing ResetScoring Rule for: correctness of response Option 2, Option 4, and Option 6 are correct.1 point for e

24、ach correct option This item references content from the following areas:CCNA Exploration1.3.3 Circuit Switched Connection Options Assessment Item:What are two advantages of an analog PSTN WAN connection? (Choose two.)low cost availability traffic encryption available bandwidth support for voice and

25、 video ResetScoring Rule for: correctness of response Option 1 and Option 2 are correct This item references content from the following areas:CCNA Exploration1.3.4 Packet Swtiched Connection Options Assessment Item:Which WAN technology uses a fixed payload of 48 bytes and is transported across both

26、switched and permanent virtual circuits?ATM ISDN Frame Relay metro Ethernet Reset View Learner ResponseScoring Rule for: correctness of response 2 points for Option 1This item references content from the following areas:CCNA Exploration1.3.4 Packet Swtiched Connection Options Assessment Item:Which t

27、hree features are identified with Frame Relay connections? (Choose three.)CIR DLCI DSLAM PVC SPID 53-byte cells ResetScoring Rule for: correctness of response Option 1, Option 2, and Option 4 are correct This item references content from the following areas:CCNA Exploration1.3.5 Internet Connection

28、Options Assessment Item:Which packet-switched WAN technology offers high-bandwidth connectivity capable of managing data, voice, and video all on the same infrastructure?Time Division Multiplexing (TDM) metro Ethernet Integrated Services Digital Network (ISDN) Public Switched Telephone Network (PSTN

29、) Reset View Learner ResponseScoring Rule for: correctness of response 2 points for Option 2This item references content from the following areas:CCNA Exploration1.2.2 WAN Physical Layer Concepts Assessment Item:Which networking device is typically used to concentrate the dial-in and dial-out traffi

30、c of multiple users to and from a network?core router access server Frame Relay switch ATM switch ResetScoring Rule for: correctness of response 2 points for Option 2This item references content from the following areas:CCNA Exploration1.2.1 WAN Technology Overview Assessment Item:Which three WAN de

31、vices can be found in the cloud? (Choose three.)ATM switches core routers CSU/DSU Ethernet switches Frame Relay switches repeaters ResetScoring Rule for: correctness of response Option 1, Option 2, and Option 5 are correct.1 point for each correct option.This item references content from the following areas:CCNA Exploration1.2.1 WAN Technology Overview Assessment Item:At which two layers of the OSI model does a WAN operate? (Choose two.)Physical Layer Data Link Layer