Cisco 642-437 Online Practice Questions and Exam Preparation

Cisco 642-437 Online Questions & Answers

• Question 181:

  Which command should you use to configure a Skinny Call Control Protocol directory number with an extension of 1003 and secondary number 9195551003?

  A. number 1003 secondary 9195551003
  B. number 1003 9195551003
  C. extension 1003 9195551003
  D. extension 1003 secondary 9195551003
  A. number 1003 secondary 9195551003

• Question 182:

  Drag the delay type on the left and drop it on the correct description on the right.

  Select and Place:

  

  

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  Processing Delay: Coder delay is the time taken by the digital signal processor (DSP) to compress a block of PCM samples. This is also called processing delay (χn). This delay varies with the voice coder used and processor speed.

  Serialization Delay: Serialization delay (σn) is the fixed delay required to clock a voice or data frame onto the network interface. It is directly related to the clock rate on the trunk.

  Dejitter Buffer: Because speech is a constant bit-rate service, the jitter from all the variable delays must be removed before the signal leaves the network. In Cisco router/gateways this is accomplished with a de-jitter (Δn) buffer at the far-end

  (receiving) router/gateway. The de-jitter buffer transforms the variable delay into a fixed delay. It holds the first sample received for a period of time before it plays it out. This holding period is known as the initial play out delay.

  DSP Delay: The time the packet spends inside the DSP is known as DSP Delay. Sampling, Encoding, Decoding etc. takes place inside the DSP.

  Queuing Delay: After the compressed voice payload is built, a header is added and the frame is queued for transmission on the network connection. Voice needs to have absolute priority in the router/gateway. Therefore, a voice frame must

  only wait for either a data frame that already plays out, or for other voice frames ahead of it. Essentially the voice frame waits for the serialization delay of any preceding frames in the output queue. Queuing delay (sn) is a variable delay and is

  dependent on the trunk speed and the state of the queue. There are random elements associated with the queuing delay.

  Propagation Delay: Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks

  http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml

• Question 183:

  Which codec complexity type allows medium-complexity codecs to be run in high-complexity mode, but with fewer (usually approximately half) of the channels available per DSP?

  A. low complexity
  B. medium complexity
  C. high complexity
  D. flex complexity
  B. medium complexity

• Question 184:

  Which queuing mechanism guarantees low-latency propagation and high-bandwidth priority?

  A. class-based weighted fair queuing
  B. low latency queuing
  C. priority queuing
  D. custom queuing
  B. low latency queuing

• Question 185:

  The file "apps31.9-1-1TH1-16.sbn" is located in the flash memory of the device. Which command should you enter on a Cisco IOS device to serve this file correctly using Trivial File Transfer Protocol?

  A. tftp-server flash:apps31.9-1-1TH1-16.sbn
  B. tftp-server apps31.9-1-1TH1-16.sbn
  C. copy tftp flash:apps31.9-1-1TH1-16.sbn
  D. tftp server:apps31.9-1-1TH1-16.sbn
  A. tftp-server flash:apps31.9-1-1TH1-16.sbn

• Question 186:

  In the destination patterns, which wildcard symbol indicates a single-digit placeholder?

  A. ()
  B. +
  C. . (period)
  D. %
  C. . (period)

• Question 187:

  What is the maximum percentage of packet loss that can be accepted on VoIP traffic?

  A. less than 5%
  C. less than 2%
  D. less than 1%
  D. less than 1%

• Question 188:

  A call is received on a voice gateway from a Session Initiation Protocol-based Internet source. The call is destined for a telephone that is connected directly to the gateway. Which type of dial- peer is considered outgoing?

  A. plain old telephone service
  B. Foreign Exchange Station
  C. Foreign Exchange Office
  D. VoIP
  A. plain old telephone service

• Question 189:

  Which signaling protocol is proprietary to Cisco?

  A. H.323
  B. SIP
  C. MGCP
  D. SCCP
  D. SCCP

• Question 190:

  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.
  B. Cisco Unified Communications Manager SRST fallback

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  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/cmesrst.ht ml