PassGuide 642-437 V3.20 (1)

PassGuide 642-437

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Cisco 642-437

Implementing Cisco Unified Communications Voice over IP

and QoS v8.0 (CVOICE v8.0)

Q&A V3.20

(C) Copyright 2006-2010 CertBible Tech LTD,All Rights Reserved.

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Question: 1What is the function of class-based marking?

A. Marking packets based onCoS value, IP precedence value, or DSCP value allows Layer 3frames to be identified and distinguished from other packets.B. Marking frames based only onCoS value or IP precedence value allows Layer 2 frames tobe identified and distinguished from other frames.C. Marking packets or frames sets information in the Layer 2 and Layer 3 headers of a packetso that the packet or frame can be identified and distinguished from other packets or frames.D. Marking frames only sets information in the Layer 2 headers of a frame so that the framecan be identified and distinguished from other packets or frames.

Answer: A

Question: 2Voice packets are arriving at a destination with a variance of between 20 and 50 ms. If the jitterbuffer has a capacity of 30 ms, what is the impact on the audio at the receiving IP phone?

A. The jitter buffer will replay the previous voice packets to replace those packets that exceed30msto avoid speech gaps.B. The audio stream at the receiving IP phone will be delayed and garbled.C. The DSP will automatically increase the jitter buffer size after sampling the range ofincoming voice packets to accommodate the wider range in variation of voice packet arrivaltimes to avoid voice gaps.D. The IP phone will negotiate, in mid-call, a lower bandwidth codec to reduce the delay in thearrival of voice packets to avoid voice gaps.

Answer: B

Question: 3Refer to the exhibit. Which type of ephone-dn is configured for the two ephones that areshown?

A. single-line-octoB. hunt lineC. shared-line, nonexclusiveD. two directory numbers with one telephone numberE. shared-line, overlayF. Octo-line

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Answer: E

Question: 4Refer to the exhibit.

Cisco Unified Communications Manager Express has been partially configured to support 6 IPphones and 12 directory numbers. The Cisco Unified Communications Manager Express willuse the IP address 10.1.130.1/24. Which two elements of the configuration are missing fromthe command output and need to be added so that phones do not auto-register, but canmanually register with Cisco Unified Communications Manager Express? (Choose two.)

A. ip address 10.1.130.1B. noreg-ephoneC. create profileD. ip source-address 10.1.130.1E. createcnf-filesF. no auto-reg-ephone

Answer: D,F

Question: 5How does LLO ensure that voice traffic is always expedited?

A. LLO adds a strict priority class to CBWFO. This class allows delay-sensitive data such asvoice to bedequeued and sent first.B. LLO uses CBWFO to prioritize voice traffic anddequeue the voice packets so that they canbe handled first.C. The strict priority queue has a higher weight than the queues in CBWFO. This weight allowsthe delay-sensitive data such as voice to bedequeued and sent first.D. The LLO strict priority queue allows delay-sensitive data such as voice to bedequeued andsent first (before packets in other queues are dequeued), giving delay-sensitive datapreferential treatment over other traffic.

Answer: D

Question: 6Your PSTN carrier sends digits to your TI PRI circuit in a digit-by-digit format. How must the T1PRI circuit be configured to support this capability?

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A. The T1 PRI controller supports either en-bloc or digit-by-digit formats natively.B. The serial interface that is associated with the T1 controller needs to include the isdnincomingvoice command.C. The T1 controller needs to include the isdn overlap-receiving command.D. The serial interface that is associated with the T1/E1 controller needs to include the isdnoverlap-receiving command.

Answer: D

Question: 7You have a Cisco Unified Border Element configured to provide H.323 to SIP interworking.Which command will verify that you have a single H.323 and a single SIP call leg when the callis placed?

A. show call active voiceB. debug voip ipipgwC. showdialpeer voiceD. debug voice dialpeer

Answer: A

Question: 8Which QoS technology provides a strict priority queuing scheme that allows delay-sensitivedata such as voice to be dequeued and sent before packets in other queues are dequeued,and also works with WFQ and CBWFQ.

A. header compressionB. IP RTP Priority and Frame Relay IP RTP PriorityC. RSVPD. low latency queuingE. FRF.12

Answer: D

Question: 9What is the decimal equivalent of the DSCP value AF21?

A. 16B. 17C. 18D. 21

Answer: C

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Question: 10DRAG DROP

A.

Answer: A


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A.

Answer: A

Question: 12A new Cisco 7965 IP phone is installed on a Cisco Unified Communications Manager Expresssystem. When the phone requests the .loads file from the TFTP server, it sees that theversions are different. What does the IP phone do to resolve this issue?

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A. The IP phone requests the SEP<mac>.cfg file and reboots.B. The IP phone attempts to obtain the new firmware file image from the TFTP server.C. The IP phone boot requests the XMLDefault.cnf.xml file and boots up.D. The IP phone does not boot up and will require manual intervention to factory reset thephone before a new firmware image can be downloaded.

Answer: B

Question: 13You are configuring a network to support voice to the PSTN. One important aspect to theconfiguration is to be able to determine the individual slot, subunit, and port number from thegateway endpoint identifier. Which signaling protocol is appropriate for this situation?

A. H.323B. SIPC. SCCPD. MGCP

Answer: D


A.

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Answer: A

Question: 15How many IP phone calls can be sent across a 64-kb/s Frame Relay link that uses the G.729codec? The sampling rate is 50 times a second, with 20 bytes per sample. There are 8 bytes ofFrame Relay header overhead with no checksum, and header compression is used.

A. 3B. 4C. 5D. 7

Answer: C

Question: 16When Cisco Unified Border Element is configured to support RSVP-based CAC, at which pointduring call setup are the RSVP path and reservation messages sent and received?

A. The path message is sent immediately after the call setup message is received and thereservation message is received after H.245 capabilities negotiation is completed.B. The reservation message is sent immediately after the call setup message is received andthe path message is received after H.225 call setup messages have been sent.C. The path and reservation messages are sent and received after the H.245 capabilitiesnegotiation is completed.D. The path and reservation messages are sent and received immediately after the call setupmessage is received.

Answer: D

Question: 17

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Which command should be included in order to trust the DSCP-marked traffic from thedistribution layer?

A. mis qos trust cosB. mis trust dscp-cosC. mis qos trust dscpD. mis qos trust dscp-cos

Answer: C

Question: 18What are the PHBs that DiffServ use?

A. resource reservation and admission controlB. default, AF, and EF PHBsC. AF, EF, and CS PHBsD. AF and EF PHBsE. default, AF, EF, and CS PHBs

Answer: E


A.

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Answer: A

Question: 20Refer to the exhibit. Your companyas QoS policy states that all traffic that is arriving at accesslayer switches from IP phones should be marked with a DSCP value of 46 and that alluntagged traffic that is arriving from a PC that is attached to an IP phone should be markedwith a CoS value of 1. Which two options will satisfy the requirements for the CoS-to-DSCPmap and are the correct QoS commands? (Choose two.)

A. mis qos 1B. mis qos map cos-dscp 0 10 18 26 34 46 48 56C. mis qos cos 1

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D. misqos map dscp 0 8 16 26 32 40 48 56E. mis qos map cos 0 8 18 26 40 48 50 56F. mis qos dscp 1

Answer: B,C

Question: 21What is the reason that an outgoing call succeeds when there is no COR list that is applied tothe incoming dial peer and a COR list is applied to the outgoing dial peer?

A. The COR list for incoming calls on the incoming dial peer is a superset of COR lists foroutgoing calls on the outgoing dial peer.B. COR lists for incoming calls on the incoming dial peer are not a superset of COR lists foroutgoing calls on the outgoing dial peer.C. The outgoing dial peer, by default, has the lowest priority.D. The incoming dial peer, by default, has the highest COR priority when no COR is applied.

Answer: D

Question: 22Refer to the exhibit. When an inbound PSTN call from 4087071222 arrives at the ISDN portthat is shown in the exhibit, which dial peer will be matched for the inbound leg?

A. Dial-peer 123, because destination-pattern takes precedence over answer-address.B. Dial-peer 2123, because answer-address takes precedence over destination-pattern.C. The matching inbound dial peer will be selected at random.D. Although dial-peer 2123 takes precedence, it will not be matched because the commanddirectinward- dial is missing.

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E. Dial-peer 123 will be matched because dial-peer 2123 will strip all the digits.

Answer: B

Question: 23Calls are failing to egress the local PSTN gateway that uses an E1 PRI circuit. Which debugcommand would be most useful in determining which dialed digits are being sent to the PSTN?

A. debug voice dial-peerB. debug isdn q921C. debug isdn q931D. ccapi inout

Answer: C

Question: 24Refer to the exhibit. An administrator is migrating a PBX telephony system to an IP Phonesolution using a fixed numbering plan. The extension numbers and PSTN DIDs cannot bechanged. Which of the following methods can be used in order to reach the individualextensions at Site B when called via the PSTN?

A. The administrator can add a 1 to the DID for Site B to become 300-555-31xxx.B. The administrator needs to map the last four digits in the DID to the extension numbers andprefix a site code.C. The administrator needs to map the last four digits in the DID to the extension numbers andprefix anintersite code.

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D. The administrator needs to map the last four digits in the DID to the extension numbersusing translation rules.E. No changes are necessary because PSTN calls are preceded with access code 9

Answer: D


A.

Answer: A

Question: 26The router with the IP address of 10.1.120.1 needs to be configured to use the device10.1.140.1 as the clock source. Which configuration command wi accomplish this task?

A. clock source 10.1.140.1B. ntp server 10.1.140.1C. clock set 10.1.140.1D. ntp source ip addr 10.1.140.1

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E. ntp client 10.1.120.1 server 10.1.140.1

Answer: B

Question: 27Which two functions are associated with a voice gateway? (Choose two.)

A. switches voice channels between connected analog and digital voice circuitsB. provides voice-messaging services to connected analog and digital voice circuitsC. interconnects two logically separate VoIP networksD. negotiates endpoint capabilitiesE. controls opening and closing of logical channels that are used to carry media streams

Answer: A,E

Question: 28Refer to the exhibit. When an inbound PSTN call to 4087071222 is received by the router thatis shown in the exhibit, what is the resulting called number?

A. 14087071222B. 11222C. 14081222D. 1222E. 4Q87071222

Answer: D

Question: 29Which three functions are associated with MGCP? (Choose three.)

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A. Control is implemented by a series of plain-text commands that are sent over UDP port2427 between Cisco Unified Communications Manager and the gateway.B. A PRI backhaul channel forwards PRI Layer 2 (0.921) signaling information via a TCPconnection from the gateway to the call agent.C. MGCP uses a separate channel for backhauling signaling information between the callagent and the gateway.D. The gateway maintains a separate dial plan for redundancy in case the call agent fails.E. Users query the call agent to determine the location of the call recipient.F. A call agent uses control messages to direct its gateways and their operational behavior.

Answer: A,C,F


A.

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Answer: A

Question: 31Refer to the exhibit. Callers dial 0 to reach an outside line. When they try to place calls todirectory services (322) or services (422), they hear the reorder tone. What needs to be editedin the dial peer to allow these calls to complete successfully?

A. The destination pattern is incorrect. It needs to start with a 9.B. A "prefix 1" statement needs to be added to the dial-peer configuration.C. The forward-digits all command needs to be applied to the dial peer.D. The destination pattern needs to be edited so that the first digit that is matched is a 0.E. The destination pattern needs to be edited so that the first digit that is matched is a 0 andthe forward-digits all command needs to be added to the dial peer.F. The destination pattern needs to be edited so that the first digit that is matched is a 1 andthe forward-digits all command needs to be added to the dial peer.G. The destination pattern needs to be edited so that the first digit that is matched is a 0 andthe forward-digits 3 command needs to be added to the dial peer.

Answer: G

Question: 32

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In which way does SIP Early Media differ from SIP Delayed Offer?

A. In SIP Early Media mode, the SDP media capabilities are exchanged in the INVITE and the200 OK messages.B. SIP Early Media uses session indicator 183.C. The INVITE message includes an SDP-formatted list of media capabilities (includingcodecs) that are supported by the originating UA.D. The 200 OK message carries an SDP message with the final media description that hasbeen selected by the terminating UA based on the received list and the locally supportedoptions.

Answer: B

Question: 33Refer to the exhibit. Which class is always present even though it is not in the configurationsnip?

A. class best-effort

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B. class class-defaultC. default classD. best-effort classE. class class-scavenger

Answer: B

Question: 34A small office needs to provide outbound dialing and inbound DID without the cost of a T1circuit.All signaling is loop-start. Which analog port configuration will support these requirements?

A. voice-port 0/0/0/description fxs-didsignal did loop-startivoice-port 0/1/0description fxosignal loop-startidial-peer voice 1 potsincoming called-number.direct-inward-dialport 0/0/0idial-peer voice 90 potsdestination-pattern 9Tport 0/1/0B. voice-port 0/0/0signal loop-startivoice-port 0/1/0signal loop-startidial-peer voice 1 potsincoming called-numberTdirect-inward-dial!dial-peer voice 90 potsdestination-pattern 9Tport 0/1/0C. voice-port 0/1/0signal did loop-start! "

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dial-peer voice 1 potsincoming called-number!dial-peer voice 90pot destination-pattern 9Tport 0/1/0D. voice-port 0/0/0signal did loop-start! "dial-peer voice 1 potsincoming called-numberdirect-inward-dialidial-peer voice 90 potsdestination-pattern 9Tport 0/0/0

Answer: B

Question: 35In which situation would an administrator configure telephony services, but not configure anyindividual ephones?

A. Phones that are controlled by Cisco Unified Communications Manager ExpressB. Cisco Unified Communications ManagerSRSTfallbackC. Cisco Unified Communications Manager Express with HSRPD. Remotely located phones that are controlled by a third-party PBXE. This is not a valid scenario.Ephones are always required.

Answer: B


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A.

Answer: A

Question: 37When configuring Cisco AutoQoS VoIP on a Cisco catalyst switch, how is the configurationperformed?

A. The autoqos voip command is applied to each interface.B. The autoqos voip command is applied globally in the switch.C. Each interface will need either the autoqos voip cisco-phone or auto qos voip trust on eachinterface, depending on the upstream deviceD. Each interface will need either the autoqos voip trust cisco-phone or auto qos voip trust trust

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on each interface, depending on the upstream device.

Answer: C

Question: 38Which types of voice ports allow a small office to provide outbound DNIS and inbound DID?

A. FXS and FXOB. FXO and E&MC. FXS and FXS-DIDD. FXS and E&ME. FXS-DID and FXO

Answer: E


A.

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Answer: A

Question: 40When a Cisco 7965 IP phone downloads an SCCP firmware file package, which file isdownloaded first by the IP phone from the TFTP server to describe the files it should requestfrom the TFTP server?

A. term45.default.loadsB. cnu45.8-4-0-79.sbnC. term65.default.loadsD. dsp45.8-4-0-79.sbnE. apps45.9-0-2ES2.sbnF. SCCP45.9-0-2SR1S.loadsG. dsp45.8-4-0-79.sbnH. jar45sccp.8-4-0-79.sbnI. cvm45sccp.8-4-0-79.sbn

Answer: A

Question: 41Which two statements are true regarding SCCP? (Choose two.)

A. SCCP requires each endpoint or gateway event to be communicated to Cisco UnifiedCommunications ManagerB. Endpoints can operate autonomously if communication with Cisco Unified CommunicationsManager is lost.C. SCCP may interoperate with H.323 endpoints if it is implemented with Cisco Unified

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Communications Manager.D. Endpoints and gateways maintain the dial plan.E. SCCP uses hex messages for communication.

Answer: A,C


A.

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Answer: A

Question: 43Refer to the exhibit. What will the class map do if a packet arrives that is marked with a CoS of6 and a DSCP value of EF?

A. The class map will match the packet and forward it to the policy map to be marked.B. The class map will not map the packet and noOoS will be applied.C. The class map will wait for the next packet in the stream to see if it has aCoS marking of 5and then forward both packets to the policy mapD. For the packet to be forwarded to the policy map, it must have aCoS of 5 and a DSCP valueof EF.

Answer: B

Question: 44How many VoIP G.729 calls can be made simultaneously over a 128-kb/s Frame Relay circuit(Layer 3) if 50 percent of the circuit is dedicated to voice and 50 percent is dedicated to data?

A. 1B. 2C. 3D. 4E. 5

Answer: B

Question: 45In a voice gateway, the configured codec complexity of the DSPs on a voice card can bechanged.

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What is the impact on the DSPs if high codec complexity is configured?

A. The codec complexity affects call density, which is the number of calls that are reconciledon the DSPs. This results in lower call density when high complexity is configured.B. With higher codec complexity, more calls can be processed.C. Lower codec complexity supports the fewest number of voice channels, provided that thelower complexity is compatible with the particular codecs that are in use.D. The DSP will process codecs that support high complexity transparently and shift to flexmode for those codecs that are not high complexity

Answer: A

Question: 46Refer to the exhibit. A new Cisco Unified Communications Manager Express system has beendeployed and the technician is trying to add the first new IP phone to the system. The phonepowers up, but it does not register with the system. The technician has verified that the phoneis getting the proper VLAN information from Cisco Discovery Protocol. The phone is alsogetting the correct IP address and TFTP server address from DHCP. The phone has beenassigned to an ephone and the correct MAC address is configured. With the informationprovided, which two of the following does the administrator need to verify to resolve thissituation? (Choose two.)

A. Verify that theip helper-address is correctly configured.B. Verify that telephony-service has been configured.C. Verify that theephone has a button assigned.D. Verify that thetftp-server path has been configured.E. Verify that the Cisco Unified Communications Manager Express service is running.F. Verify that the correct phone type files are in thetftp-server path

Answer: D,F

Question: 47How does Packet Loss Concealment improve voice quality?

A. Cisco Packet Loss Concealment technology decreases the voice sampling rate to 10 ms ofthe voice payload to smooth gaps in the voice stream.B. Packet Loss Concealment intelligently analyzes missing packets and generates areasonable replacement packet to improve the voice qualityC. Packet Loss Concealment will buffer 20 to 50 ms of a voice stream to minimize lost or

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out-oforder voice packets.D. Packet Loss Concealment will compensate for packet loss rates between 1 and 5 percentby generating a reasonable replacement packet to improve the voice quality.

Answer: B

Question: 48Which three methodologies are specific types of QoS used on a 512-kb/s point-to-point IPWAN link? (Choose three.)

A. header compressionB. FRF.12C. LLQD. MultilinkPPPE. RSVP

Answer: A


A.

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Answer: A

Question: 50Which three of the following methods are used by a Cisco Unified Border Element to providenetwork hiding? (Choose three.)

A. back-to-back user agent, replacing all H.323-embedded IP addressingB. IP network security boundaryC. media flow-throughD. RSVPE. IP network privacyF. intelligent IP address translation for call media and RTP flows

Answer: B,E,F


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A.

Answer: A

Question: 52Refer to the exhibit. Consider an outgoing call that is being placed in all three scenarios thatare shown in the exhibit. What is the result of the call, going down the table from top tobottom?

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A. success,success,successB. success, success, failC. success, fail, successD. success, fail, failE. fail, success, successF. fail, success, fail

Answer: A

Question: 53Which three Cisco IOS commands are required to configure a voice gateway as a DHCPserver to support a data subnet with the IP address of 10.1.30.0/24 and a default gateway of10.1.30.1/24? (Choose three.)

A. ip dhcp poolB. subnet 10.1.30.1 255.255.255.0C. ip dhcp pool dataD. network 10.1.30.1/24E. network 10.1.30.0 255.255.255.0F. default-gw 10.1.30.1J24G. default-router 10.1.30.1

Answer: C,E,G

Question: 54Refer to the exhibit. When an international call to 90114989531212001 is placed fromextension 2001, which of the following statements is true?

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A. The call will fail because no incoming COR list is applied.B. The call will succeed because the incoming COR list is a superset of the outgoing COR list.C. The call will fail because the incoming COR list is not a superset of the outgoing COR list.D. The call will succeed because the incoming COR list has the highest priority, by default,when no incoming COR list is applied.

Answer: D

Question: 55In which situation would the trust boundary be located at the access layer?

A. if the endpoints, both IP phones and PCs, are incapable of marking traffic properlyB. if PCs are switched through an IP phone and the IP phone traffic can be trusted to markboth traffic streams properlyC. if the access layer switch cannot trust or re-mark incoming traffic from endpoints properlyD. if there are endpoints that cannot be trusted and connect directly to the distribution layer

Answer: B

Question: 56An access layer switch is configured to extend priority to an IP phone. Cisco DiscoveryProtocol is enabled on all ports. What are the three possible ways that an IP phone can beinstructed to treat the Layer 2 CoS priority value of the attached PC? (Choose three.)

A. trusted IEEE 802.1Q

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B. configured DSCP levelC. configuredCoS levelD. trustedE. configured IEEE 802.1QF. untrusted

Answer: A,C,D

Question: 57Refer to the exhibit. When 5551234 is being matched with the outgoing dial peer that is shownin the exhibit, which of the following called numbers will be sent to the PSTN?

A. 5551234B. 1234C. 555D. NullE. 5F. 51234

Answer: F


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A.

Answer: A


A.

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Answer: A

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PassGuide 642-437 V3.20 (1)