642-432 Cisco Voice Over IP Exam(CVOICE)

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Question 1

At what point does the MGCP call agent release the setup of the call path to the residential

  • A. after the call agent has been notified that an event occurred at the source residential gateway
  • B. after the call agent has been notified of an event and has instructed the source residential gateway to create a connection
  • C. does not release call path setup
  • D. after the call agent has sent a connection request to both the source and destination and has relayed a modify-connection request to the source so that the source and destination can set up the call path
  • E. after the call agent has forwarded session description protocol information to the destination from the source and has sent a modify connection to the destination and a create-connection request to the source

Answer : D

Question 2

Given the SIP network shown in the diagram, identify which two actions are initiated by the
UAS (user agent server)? (Choose two.)

  • A. contacts the user when a SIP invitation is received
  • B. originates the ACK method to indicate that it has received a response to an invitation
  • C. originates the BYE method to initiate call termination
  • D. originates the INVITE method including a description of the session parameters
  • E. returns a response on behalf of the user to the invitation originator

Answer : A,E

Question 3

What are two basic parameters needed to setup a dial peer connected to the PSTN?
(Choose two.)

  • A. voice port
  • B. signaling type
  • C. interface bandwidth
  • D. destination pattern

Answer : A,D

Question 4

Which preference key word assigns top precedence to a dial peer in a hunt-group?

  • A. 0
  • B. priority
  • C. 1
  • D. high

Answer : A

Question 5

How is CAS different on E1 and T1?

  • A. T1 has more signaling channels.
  • B. E1 CAS signaling is out-of-band while T1 is in-band.
  • C. E1 uses robbed-bit signaling.
  • D. T1 uses the D channel for CAS signaling.

Answer : B

Question 6

You are working with a potential customer that would like to integrate its existing PBX
telephone system into its IP network. The accompanying figure shows that the customer
has two offices that need to be connected to the IP network so that the customer can
exchange telephone calls without using the PSTN. Both PBXs use a proprietary signaling
Which signaling type will allow you to support your customer?

  • A. E&M
  • B. CCS
  • C. CAS
  • D. T-CCS
  • E. FXO
  • F. FXS

Answer : D

Question 7

How do a-law and mu-law handle issues with signal-to-noise ratios related to the measure
of amplitude?

  • A. Use smaller step functions at lower amplitudes.
  • B. Use smaller step functions at higher frequencies.
  • C. Increase code points at lower amplitudes.
  • D. Increase code points at higher frequencies.

Answer : A

Question 8

You have been forwarded some questions by a prospective VoIP customer who would like
to know the Cisco default sample size for the G.729 codec. What is it?

  • A. 40 ms
  • B. 30 ms
  • C. 20 ms
  • D. 10 ms

Answer : C

Question 9

Examine the following PBX system parameters:
The calling side seizes the line by going off-hook on its E-lead and sends information as
DTMF digits.
The voice path is 4-wires, and the voice enabled router is in another building from the PBX.
Select the correct set of commands to allow communication between a voice enabled
router and a PBX.

  • A. voice port 1/0/0 signal immediate-start operation 4-wire type 2
  • B. voice-port 1/0/0 signal delay-dial operation 4-wire type 1
  • C. voice port 1/0/0 signal wink-start operation 4-wire type 3
  • D. voice port 1/0/0 signal immediate-start operation 4-wire type 4

Answer : A

Question 10

Which option is true concerning the MGCP call agent?

  • A. acts only as a recorder of call details
  • B. provides only call signaling and call setup
  • C. manages all aspects of the call and voice stream
  • D. monitors the quality of each call after setup

Answer : B

Question 11

Which problem does a-law and mu-law address?

  • A. quantization produces distortion at higher frequencies
  • B. encoding loses signal integrity at lower frequencies
  • C. quantization produces higher signal-to-noise ratios at smaller amplitudes
  • D. encoding produces greater signal loss at higher amplitude

Answer : C

Question 12

What are the three components in an MGCP environment? (Choose three.)

  • A. gateway
  • B. gatekeeper
  • C. endpoint
  • D. call agent
  • E. proxy server

Answer : A,C,D

Question 13

What is the approximate frequency range of human speech?

  • A. 20 Hz to 20,000 Hz
  • B. 40 Hz to 15,000 Hz
  • C. 200 Hz to 9000 Hz
  • D. 600 Hz to 5400 Hz

Answer : C

Question 14

King's Mountain Cable has a pair of voice enabled routers capable of supporting only high
complexity codecs. They need to conserve bandwidth on WAN links without major impact
to call quality. Which two codecs satisfy these requirements? (Choose two.)

  • A. G.729
  • B. G.729a
  • C. G.729b
  • D. G.729ab

Answer : B,D

Question 15

Examine the example output.
hostname GW1
interface Ethernet 0/0
ip address
h323-gateway voip interface
h323-gateway voip id GK1-zone1.abc.com abc.com ipaddr
h323-gateway voip h323-id GW1
h323-gateway voip bind srcaddr
dial-peer voice 1 voip
destination-pattern 1212.
session-target ras
dial-peer voice 2 pots
destination-pattern 2125551212
no register e164
Choose the command that will restore communication with gatekeeper functionality to this

  • A. h323-gateway voip h323-id GK1
  • B. gateway
  • C. h323-gateway voip bind srcaddr
  • D. h323-gateway voip GW1-zone2.abc.com abc.com ipaddr

Answer : B

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