Accessing the WAN - Chapter 1

1 Atwhichtwolayers of the OSI model does a WAN operate? (Choosetwo.) Physical Layer Data Link Layer Network Layer Transport Layer Presentation Layer Application Layer Observable Description Max Value 1 correctness of response Option 1 and Option 2 are correct. * 1.2.1 WAN TechnologyOverview 2 Whichthree WAN devicescanbefound in the cloud? (Choosethree.) ATM switches corerouters CSU/DSU Ethernet switches Frame Relay switches repeaters Observable Description Max Value 1 correctness of response Option 1, Option 2, and Option 5 are correct. * 1.2.1 WAN TechnologyOverview 3 Which networking deviceistypicallyused to concentrate the dial-in and dial-out traffic of multiple users to and from a network? core router access server Frame Relay switch ATM switch

Observable Description Max Value 1 correctness ofresponse 2 points for Option 2 * 1.2.2 WAN Physical Layer Concepts 4 Whichpacket-switched WAN technologyoffershigh-bandwidthconnectivity capable of managing data, voice, and video all on the same infrastructure? Time Division Multiplexing (TDM) metro Ethernet Integrated Services Digital Network (ISDN) Public SwitchedTelephone Network (PSTN) Observable Description Max Value 1 correctness of response 2 points for Option 2 * 1.3.5 Internet Connection Options 5 Whichthreefeatures are identifiedwith Frame Relay connections? (Choosethree.) CIR DLCI DSLAM PVC SPID 53-byte cells Observable Description Max Value 1 correctness of response Option 1, Option 2, and Option 4 are correct. * 1.3.4 PacketSwtichedConnection Options 6 Which WAN technology uses afixedpayload of 48 bytes and istransportedacrossbothswitched and permanent virtual circuits? ATM ISDN Frame Relay metro Ethernet

Observable Description Max Value 1 correctness of response 2 points for Option 1 * 1.3.4 PacketSwtichedConnection Options 7 What are twoadvantages of an analog PSTN WAN connection? (Choosetwo.) lowcost availability trafficencryption availablebandwidth support for voice and video Observable Description Max Value 1 correctness of response Option 1 and Option 2 are correct. * 1.3.3 Circuit SwitchedConnection Options 8 Whatthreeterms are associatedwith ISDN PRI? (Choosethree.) cell DLCI circuit switching packetswitching data bearerchannels time-division multiplexing Observable Description Max Value 1 correctness of response Option 3, Option 5, and Option 6 are correct.. * 1.3.3 Circuit SwitchedConnection Options 9 Whatcan cause areduction in availablebandwidth on a cablebroadbandconnection? smallercells number of subscribers committed information rate

distance from the central office of the provider Observable Description Max Value 1 correctness of response 2 points for Option 2 * 1.3.5 Internet Connection Options 10 What type of connectivityisestablishedwhenVPNs are usedfrom the remote site to the private network? PVCs DLCIs tunnels dedicated Layer 2 links Observable Description Max Value 1 correctness ofresponse 2 points for Option 3 * 1.3.5 Internet Connection Options 11 A U.S. companyrequires a WAN connectionusedonly to transfer sales data fromindividual stores to the home office. All transferswilloccurafter business hours. The requiredbandwidth for thisconnectionisestimated to belessthan 38 kbps. Which type of connectionrequires the least investment for thiscompany? ATM ISDN analogdialup T1 Leased Line Observable Description Max Value 1 correctness ofresponse 2 points for Option 3 * 1.3.3 Circuit SwitchedConnection Options 12 For digital lines, whichdeviceisused to establish the communications linkbetween the customerequipment and the local loop?

CSU/DSU Frame Relay switch ISDN switch modem PBX switch Observable Description Max Value 1 correctness ofresponse 2 points for Option 1 * 1.2.2 WAN Physical Layer Concepts 13 Whichtermdescribes a devicethatwill put data on the local loop? DLCI DTE DCE BRI PRI Observable Description Max Value 1 correctness ofresponse 2 points for Option 3 * 1.2.2 WAN Physical Layer Concepts 14 Whichswitching type willallow the communication devices in the provider network to beshared and onlyallocated to an individualsubscriberduring data transfer? circuit-switched dedicatedswitchedlines frame-switched packet-switched Observable Description Max Value 1 correctness ofresponse 2 points for Option 4 * 1.2.4 WAN Switching Concepts 15 A companyneeds a WAN connectionthatis capable of transferringvoice, video, and

data at a minimum data rate of 155 Mbps. Which WAN connectionis the best choice? X.25 DSL ATM ISDN BRI ISDN PRI Observable Description Max Value 1 correctness ofresponse 2 points for Option 3 * 1.3.4 PacketSwtichedConnection Options 16 Whichtwodevices are commonlyused as data communications equipment? (Choosetwo.) modem router CSU/DSU ISDN switch Ethernet switch Observable Description Max Value 1 correctness of response Option 1 and Option 3 are correct. * 1.2.2 WAN Physical Layer Concepts 17 Whichstatementistrue of the functionality of the layers in the hierarchical network model? The purpose of the accesslayeris to provideveryhighbandwidth communi cations between network devices. Most security screening to preventunauthorized entry to the network happensat the corelayer. Untrustedexternal connections are segmentedfrom the rest of the network at all threelevels. The distribution layer aggregates WAN connections at the edge of the campus.

Observable Description Max Value 1 correctness ofresponse 2 points for Option 4 * 1.1.3 The Evolving Network Model 18 Whichstatementistrue about data connectivitybetween a customer and a service provider? Normally the CSU/DSU is the designateddemarcation point for the service provider but not the customer. The segment between the demarcation point and the central office isknown as the "last mile." The local loopis the segment between the CSU/DSU and the serial port on a router. Putting data on the local loopis the responsibility of the DTE. Observable Description Max Value 1 correctness ofresponse 2 points for Option 2 * 1.2.2 WAN Physical Layer Concepts 19 Whichstatementistrue about the differencesbetween a WAN and a LAN? WANsgenerally support higherbandwidththanLANs support. A WAN linktypically traverses shortergeographic distances than a LAN link traverses. A WAN often relies on the services of carriers, such as telephone or cablecompanies, but a LAN does not. All WAN implementationsgenerally use the same Layer 2 protocol but there are manyaccepted LAN Layer 2 protocols in use. Observable Description Max Value 1 correctness of response 2 points for Option 3 20 Whyis the call setup time of a circuit-switched WAN implementationconsidered a drawback? Routingprotocols are incompatible withthisfunction. It restricts the communication sent to voicetrafficonly. A telephone must beused to initiallystarttransferring data.

Data cannotbetransferreduntila circuit has been established. Observable Description Max Value 1 correctness ofresponse 2 points for Option 4 * 1.2.4 WAN Switching Concepts 21 Whichstatement about WAN protocolsis correct? ATM differsfromother WAN protocols in thatit uses variablysizedpackets. Most WAN protocols use HDLC or a variant of HDLC as a framingmechanism. The frame header consists of the frame check sequence and cyclicredundancy check. ISDN differsfrom Frame Relay, HDLC, and ATM in thatitispacketswitchedratherthan circuit-switchedtechnology. Observable Description Max Value 1 correctness of response 2 points for Option 2 * 1.2.3 WAN Data Link Layer Concepts 22 Whatis an advantage of packet-switchedtechnology over circuit-switchedtechnology? Packet-switched networks are less susceptible to jitterthan circuit-switched networks are. Packet-switched networks canefficiently use multiple routes insidea service provider network. Packet-switched networks do not require an expensive permanent connection to eachendpoint. Packet-switched networks usuallyexperiencelowerlatencythan circuit-switched networks experience. Observable Description Max Value 1 correctness ofresponse 2 points for Option 2 * 1.2.4 WAN Switching Concepts