DRAG DROP
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Cisco 642-437 Exam
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Explanation/Reference:
Explanation:
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Cisco 642-437 Exam
Processing Delay: Coder delay is the time taken by the digital signal processor (DSP) to compress a blockof PCM samples. This is also called processing delay (n). This delay varies with the voice coder used andprocessor speed.
Serialization Delay: Serialization delay (n) is the fixed delay required to clock a voice or data frame onto thenetwork interface. It is directly related to the clock rate on the trunk. Dejitter Buffer: Because speech is aconstant bit-rate service, the jitter from all the variable delays must be removed before the signal leaves thenetwork. 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 samplereceived 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 fortransmission 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 voiceframes ahead of it. Essentially the voice frame waits for the serialization delay of any preceding frames inthe output queue. Queuing delay (ßn) is a variable delay and is dependent on the trunk speed and the stateof the queue. There are random elements associated with the queuing dela
Propagation Delay: Caused by the length a signal must travel via light in fiber or electrical impulse incopper-based networks
http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml
Cisco 642-437 Exam
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