Cisco Implementing Cisco Unified Communications Voice over IP and QoS v8.0 (CVOICE v8.0) - 642-437 Exam Practice Test
Which of the available quality of service models offers the greatest amount of scalability while maintaining service quality?
Correct Answer: B
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Which QoS technology ensures predictability for voice traffic, aiming to provide better throughput on low-speed Frame Relay links?
Correct Answer: C
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Calls are failing to reach the E1 PRI circuit on the PSTN gateway. Which command would be useful in determining if the dial peers are configured properly?
Correct Answer: E
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How are firmware images implemented and which file type describes the contents of the firmware image?
Correct Answer: A
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Which networking feature typically is used on an IP phone that is also connected to a local computer to maintain separation between the voice and data traffic?
Correct Answer: B
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Which QoS mechanism for VoIP works with weighted fair queuing (WFQ) and class-based weighted fair queuing (CBWFQ)?
Correct Answer: D
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Refer to the exhibit.
Cisco 642-437 Exam
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?
Cisco 642-437 Exam
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?
Correct Answer: D
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DRAG DROP
Drag the delay type on the left and drop it on the correct description on the right.
Drag the delay type on the left and drop it on the correct description on the right.
Correct Answer:
Explanation:
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 (n). This delay varies with the voice coder used and processor speed. Serialization Delay: Serialization delay (n) 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 (n) 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 (Bn) 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
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