Download New Latest (May) Cisco 642-437 Actual Tests 31-40

Ensurepass

 

QUESTION 31  (Topic 1)

 

Refer to the exhibit.

 

 

 

clip_image001

 

What happens when users at Site B place calls to Site A when the IP WAN is operational?

 

A.

The calls will always take the IP WAN route.

B.

The calls will always take the PSTN route.

C.

The calls will fail because the destination patterns are identical.

D.

The calls will use round-robin scheduling between the IP WAN and PSTN paths.

E.

The calls will use the IP WAN route unless there is a failure or congestion during which

 

 

the calls will reroute via the PSTN.

 

Answer: D

 

 

QUESTION 32  (Topic 1)

 

In which situation would an administrator configure telephony services, but not configure any individual ephones?

 

A.

Phones that are controlled by Cisco Unified Communications Manager Express

B.

Cisco Unified Communications Manager SRST fallback

C.

Cisco Unified Communications Manager Express with HSRP

D.

Remotely located phones that are controlled by a third-party PBX

E.

This is not a valid scenario. Ephones are always required.

 

Answer: B

Explanation: When a phone registers for SRST service with a Cisco Router and the router discovers that the phone was configured with a specific extension number, the router searches for an existing prebuilt ephone-dn with that extension number and then assigns that ephone-dn number to the phone. If there is no prebuilt ephone-dn with that extension number, the system automatically creates one. In this way, extensions without prebuilt configurations are automatically populated with extension numbers and features as the numbers and features are “learned” by the Cisco router in SRST mode when the phone registers to the router after a WAN link fails.

 

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guide/cmesr st.html

 

 

QUESTION 33  (Topic 1)

 

How does LLQ ensure that voice traffic is always expedited?

 

A.

LLQ adds WRED to CBWFQ. This allows delay-sensitive data such as voice to be dequeued and sent first.

B.

LLQ uses CBWFQ to prioritize voice traffic and by dequeuing the voice packets so they can be handled first.

C.

The strict priority queue has a higher weight than the queues in CBWFQ. This weight allows the delay-sensitive data such as voice to be dequeued and sent first.

D.

The LLQ strict priority queue allows delay-sensitive data such as voice to be dequeued and sent first (before packets in other queues are dequeued), giving delay-sensitive data preferential treatment over other traffic.

 

Answer: D

Explanation: Without Low Latency Queueing, CBWFQ provides weighted fair queueing based on defined classes with no strict priority queue available for real-time traffic. This scheme poses problems for voice traffic that is largely intolerant of delay, especially variation in delay. For voice traffic, variations in delay introduce irregularities of transmission manifesting as jitter in the heard conversation. The Low Latency Queueing feature provides strict priority queueing for CBWFQ, reducing jitter in voice conversations. Configured by the priority command, Low Latency Queueing enables use of a single, strict priority queue within CBWFQ at the class level, allowing you to direct traffic belonging to a class to the CBWFQ strict priority queue.

http://www.cisco.com/en/US/docs/ios/12_0t/12_0t7/feature/guide/pqcbwfq.html

 

 

QUESTION 34  (Topic 1)

 

Which four types of ephone-dns are supported by SCCP in Cisco Unified Communications Manager Express? (Choose four.)

 

A.

single-line

B.

dual-line

C.

shared-line, nonexclusive

D.

two directory numbers with one telephone number

E.

dual-number

F.

octo-line

 

Answer: ABEF

 

 

QUESTION 35  (Topic 1)

 

Refer to the exhibit.

 

 

 

clip_image002

 

When an inbound PSTN call from 4087071222 arrives at the ISDN port that 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 21
23, 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 command direct-inward-dial is missing.

E.

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

 

Answer: B

Explanation: The inbound call will first try to match the with the incoming called-number command. We can also use `answer-address command’ which is searched if `incoming called-number’ is not present. And if there is no `incoming called-number command’ and `answer-address command’, then the gateway will hunt for dialpeer with destination-pattern of calling party number.

http://www.cisco.com/en/US/docs/ios/12_3/vvf_c/dial_peer/dp_confg.html#wp1067989

 

 

QUESTION 36  (Topic 1)

 

Refer to the exhibit. An administrator is migrating a PBX telephony system to an IP Phone solution using a fixed numbering plan. The extension numbers and PSTN DIDs cannot be changed. Which of the following methods can be used in order to reach the individual extensions at Site B when called via the PSTN?

 

clip_image003

 

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 and prefix a site code.

C.

The administrator needs to map the last four digits in the DID to the extension numbers and prefix an intersite code.

D.

The administrator needs to map the last four digits in the DID to the extension numbers using translation rules.

E.

No changes are necessary because PSTN calls are preceded with access code 9.

 

Answer: D

Explanation: Since the extension and PSTN DID is one and the same for the customer, no manipulation is required the Route Plan to reach individual extensions from PSTN DID

 

 

QUESTION 37  (Topic 1)

 

What is the reason that an outgoing call succeeds when there is no COR list that is applied to the 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 for outgoing calls on the outgoing dial peer.

B.

COR lists for incoming calls on the incoming dial peer are not a superset of COR lists for outgoing 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

Explanation: By default, an incoming call leg has the highest COR priority and the outgoing COR list has the lowest COR priority. This means that if there is no COR configuration for incoming calls on a dial-peer, then you can make a call from this dial-peer (a phone attached to this dial-peer) going out of any other dial-peer, irrespective of the COR configuration on that dial-peer.

http://www.cisco.com/en/US/tech/tk652/tk90/technologies_configuration_example09186a0 08019d649.shtml

 

 

QUESTION 38  (Topic 1)

 

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

 

 

 

clip_image004

 

A.

14087071222

B.

11222

C.

14081222

D.

1222

E.

4087071222

 

Answer: D

Explanation: /^.*(….$) ?Truncates Numbers down to the last 4 digits. http://www.cisco.com/en/US/tech/tk652/tk90/technologies_tech_note09186a0080325e8e.s html

 

 

QUESTION 39  (Topic 1)

 

Assuming no cRTP or header compression. How 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.

1

B.

2

C.

3

D.

4

E.

5

 

Answer: B

Explanation:Bandwidth Calculation Formulas

These calculations are used:

Total packet size = (L2 header: MP or FRF.12 or Ethernet) + (IP/UDP/RTP header) + (voice payload size)

Codec bit rate = codec sample size / codec sample interval PPS = (codec bit rate) / (voice payload size)

Bandwidth = total packet size * PPS

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.

shtml

 

 

QUESTION 40  (Topic 1)

 

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

 

A.

switches voice channels between connected analog and digital voice circuits

B.

provides voice-messaging services to connected analog and digital voice circuits

C.

interconnects two logically separate VoIP networks

D.

negotiates endpoint capabilities

E.

controls opening and closing of logical channels that are used to carry media streams

 

Answer: AE

Explanation: The basic function of a gateway is to translate between differen
t types of networks. In a VoIP environment, voice gateways are the interface between a VoIP network and the public switched telephone network (PSTN), a private branch exchange (PBX), or analog devices such as fax machines. In its simplest form, a voice gateway has an IP interface and a legacy telephone interface, and it handles the many tasks involved in translating between transmission formats and protocols. The gateway allows communication between the two networks by performing tasks such as Interfacing with the IP network and the PSTN or PBX, Supporting IP call control protocols, Performing call setup and teardown for calls between the VoIP and PSTN networks by terminating and reoriginating the call media and signaling, Providing supplementary services, such as call hold and transfer, Relaying dual tone multifrequency (DTMF) tones, Supporting analog fax and modems over the IP network.

http://www.cisco.com/en/US/prod/collateral/routers/ps5854/product_data_sheet0900aecd8

 

 

 

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