This chapter covers the following subjects:
- Introduction to QoS
- Identifying and Comparing QoS Models
- QoS Implementation Methods
This chapter provides the essential background, definitions, and concepts for you to start learning IP quality of service (QoS). The following two chapters complement this one and provide more coverage of this topic. It is probably safe to expect about 20 percent of the ONT exam questions from this chapter.
"Do I Know This Already?" Quiz
The purpose of the "Do I Know This Already?" quiz is to help you decide whether you really need to read the entire chapter. The 20-question quiz, derived from the major sections of this chapter, helps you determine how to spend your limited study time.
Table 2-1 outlines the major topics discussed in this chapter and the "Do I Know This Already?" quiz questions that correspond to those topics. You can keep track of your score here, too.
Table 2-1. "Do I Know This Already?" Foundation Topics Section-to-Question Mapping
Foundation Topics Section Covering These Questions |
Questions |
Score |
"Introduction to QoS" |
1–7 |
|
"Identifying and Comparing QoS Models" |
8–13 |
|
"QoS Implementation Methods" |
14–20 |
|
Total Score |
(20 possible) |
You can find the answers to the "Do I Know This Already?" quiz in Appendix A, "Answers to the 'Do I Know This Already?' Quizzes and Q&A Sections." The suggested choices for your next step are as follows:
- 15 or less overall score—Read the entire chapter. This includes the "Foundation Topics," "Foundation Summary," and "Q&A" sections.
- 16–17 overall score—Begin with the "Foundation Summary" section and then follow up with the "Q&A" section at the end of the chapter.
- 18 or more overall score—If you want more review on this topic, skip to the "Foundation Summary" section and then go to the "Q&A" section. Otherwise, proceed to the next chapter.
-
Which of the following items is not considered one of four major issues and challenges facing converged enterprise networks?
- Available bandwidth
- End-to-end delay
- Delay variation (jitter)
- Packet size
-
Which of the following is defined as the maximum bandwidth of a path?
- The bandwidth of the link within the path that has the largest bandwidth
- The bandwidth of the link within the path that has the smallest bandwidth
- The total of all link bandwidths within the path
- The average of all the link bandwidths within the path
-
Which of the following is not considered one of the main methods to tackle the bandwidth availability problem?
- Increase (upgrade) the link bandwidth.
- Classify and mark traffic and deploy proper queuing mechanisms.
- Forward large packets first.
- Use compression techniques.
-
Which of the following is not considered a major delay type?
- Queuing delay
- CEF (Cisco Express Forwarding) delay
- Serialization delay
- Propagation delay
-
Which of the following does not reduce delay for delay-sensitive application traffic?
- Increasing (upgrade) the link bandwidth
- Prioritizing delay-sensitive packets and forwarding important packets first
- Layer 2 payload encryption
- Header compression
-
Which of the following approaches does not tackle packet loss?
- Increase (upgrade) the link bandwidth.
- Increase the buffer space.
- Provide guaranteed bandwidth.
- Eliminate congestion avoidance.
-
Which of the following is not a major step in implementing QoS?
- Apply access lists to all interfaces that process sensitive traffic
- Identify traffic types and their requirements
- Classify traffic based on the requirements identified
- Define policies for each traffic class
-
Which of following is not one of the three main QoS models?
- MPLS QoS
- Differentiated services
- Best effort
- Integrated services
-
Which two of the following items are considered drawbacks of the best-effort model?
- Inability to scale
- Lack of service guarantee
- Lack of service differentiation
- Difficulty in implementing (complexity)
-
Which of the following is not a function that IntServ requires to be implemented on the routers along the traffic path?
- Admission control and policing
- Classification
- Queuing and scheduling
- Fast switching
-
Which of the following is the role of RSVP within the IntServ model?
- Routing
- Switching
- Signaling/Bandwidth Reservation
- Caching
-
Which of the following is not considered a benefit of the IntServ model?
- Explicit end-to-end resource admission control
- Continuous signaling per active flow
- Per-request policy admission control
- Signaling of dynamic port numbers
-
Which of the following is not true about the DiffServ model?
- Within the DiffServ model, QoS policies (are deployed to) enforce differentiated treatment of the defined traffic classes.
- Within the DiffServ model, classes of traffic and the policies are defined based on business requirements; you choose the service level for each traffic class.
- Pure DiffServ makes extensive use of signaling; therefore, it is called hard QoS.
- DiffServ is a scalable model.
-
Which of the following is not a QoS implementation method?
- Cisco IOS CLI
- MQC
- Cisco AVVID (VoIP and Enterprise)
- Cisco SDM QoS Wizard
-
Which of the following is not a major step in implementing QoS with MQC?
- Define traffic classes using the class map.
- Define QoS policies for the defined traffic classes using the policy map.
- Apply the defined policies to each intended interface using the service-policy command.
- Enable AutoQoS.
-
Which of the following is the simplest QoS implementation method with an option specifically for VoIP?
- AutoQoS (VoIP)
- CLI
- MQC
- Cisco SDM QoS Wizard
-
Select the most time-consuming and the least time-consuming QoS implementation methods.
- CLI
- MQC
- AutoQoS
- Cisco SDM QoS Wizard
-
What is the most significant advantage of MQC over CLI?
- It requires little time to implement.
- It requires little expertise to implement.
- It has a GUI and interactive wizard.
- It separates traffic classification from policy definition.
-
Before you enable AutoQoS on an interface, which two of the following must you ensure have been configured on that interface?
- Cisco modular QoS is configured.
- CEF is enabled.
- The SDM has been enabled.
- The correct bandwidth on the interface is configured.
-
Select the item that is not a main service obtained from SDM QoS.
- It enables you to implement QoS on the network.
- It enables you to fine-tune QoS on the network.
- It enables you to monitor QoS on the network.
- It enables you to troubleshoot QoS on the network.