Q&A

As mentioned in the Introduction, you have two choices for review questions. The questions that follow next give you a more difficult challenge than the exam itself by using an open-ended question format. By reviewing now with this more difficult question format, you can exercise your memory better, and prove your conceptual and factual knowledge of this chapter. You can find the answers to these questions in Appendix A.

The second option for practice questions is to use the CD-ROM included with this book. It includes a testing engine and more than 200 multiple-choice questions. You should use this CD-ROM nearer to the end of your preparation, for practice with the actual exam format.

1.	List the four traffic characteristics that QoS tools can affect.
2.	Describe some of the characteristics of voice traffic when no QoS is applied in a network.
3.	Describe some of the characteristics of video traffic when no QoS is applied in a network.
4.	Describe some of the characteristics of data traffic when no QoS is applied in a network.
5.	Interpret the meaning of the phrase, "QoS is both 'managed fairness,' and at the same time 'managed unfairness'."
6.	Define bandwidth. Compare and contrast bandwidth concepts over point-to-point links versus Frame Relay.
7.	Compare and contrast bandwidth and clock rate in relation to usage for QoS.
8.	List the QoS tool types that affect bandwidth, and give a brief explanation of why each tool can affect bandwidth.
9.	Define delay, compare/contrast one-way and round-trip delay, and characterize the types of packets for which one-way delay is important.
10.	List the categories of delay that could be experienced by all three types of traffic: data, voice, and video.
11.	Define, compare, and contrast serialization and propagation delay.
12.	Define network delay.
13.	List the QoS tool types that affect delay and give a brief explanation of why each tool can affect delay.
14.	Define jitter. Give an example that shows a packet without jitter, followed by a packet with jitter.
15.	List the QoS tool types that affect jitter and give a brief explanation of why each tool can affect jitter.
16.	Define packet loss and describe the primary reason for loss for which QoS tools can help.
17.	List the QoS tool types that affect loss and give a brief explanation of why each tool can affect loss.
18.	Describe the contents of an IP packet carrying the payload for a G.729 VoIP call.
19.	Describe the amount of bandwidth required for G.711 and G.729 VoIP calls, ignoring data-link header/trailer overhead.
20.	List the delay components that voice calls experience, but which data-only flows do not experience.
21.	Define the meaning of the term "packetization delay" in relation to a voice call.
22.	List the different one-way delay budgets as suggested by Cisco and the ITU.
23.	Define the term "codec delay" and discuss the two components when using a G.729 codec.
24.	Describe the affects of a single lost packet versus two consecutive lost packets, for a G.729 voice call.
25.	Describe a typical video payload flow in terms of packet sizes and packet rates.
26.	Discuss the delay requirements of video traffic.
27.	List the basic differences between TCP and UDP traffic.
28.	Contrast the QoS characteristics needed by interactive data applications, as compared to the QoS needs of voice payload flows.
29.	What are the three steps suggested in this chapter for planning QoS policy implementation?
30.	The chapter provides a suggested process for planning and implementing QoS policies. The first step involves identifying traffic classes and requirements. That step lists two specific types of audits that should be performed in this step. List and give a brief description of the two audit steps.
31.	Early in the chapter, a couple of different definitions of QoS were supplied. Paraphrase your own general definition of the term "QoS".
32.	What is the purpose of service classes when implementing a QoS policy?