Exam : Cisco 642-642
Title : Quality of Service (QOS)


1. SLA(Service-Level Agreement) is a contract between a network service provider and a customer, which usually defines such terms as the type of service, the quality of service and the customer's payment. In an unmanaged CE router implementation, how does the service provider enforce the SLA?
A. by using class-based policing on the CE to PE link to limit the customer's input rate
B. by using class-based random discard on the CE to PE link to limit the customer's input rate
C. by marking on the CE to PE link and using CBWFQ and CB-WRED on the PE to P link
D. by marking on the CE to PE link and using class-based policing on the PE to P link
Answer: A

2. The SF and SJ routes are running OSPF as the routing protocol. Since a policy-map applied to the SF router s0/0 interface, the SF and SJ routers are no longer able to establish full OSPF adjacency between them. On the basis of the SF router configuration and various show outputs from the SF router. Which change to the policy-map in the SF router configuration could solve the OSPF problem?
A. Provide a bandwidth guarantee to the class-defalut traffic class using bandwidth percent 25.
B. Change bandwidth percent 5 for the cs6 traffic class to bandwidth percent 25.
C. Change bandwidth percent 5 fot the cs6 traffic class to priority 8.
D. Use the no police 8000 conform-action drop exceed-action transmit command for the cs6 traffic class.
Answer: D

3. WFQ(Weighted Fair Queuing) is a data packet scheduling technique allowing different scheduling priorities to statistically multiplexed data flows. For the following statements, what are two benefits of WFQ? (Choose two.)
A. WFQ is very easy to configure, and no manual traffic classification is necessary.
B. WFQ can provide fixed-delay guarantees.
C. WFQ can provide fixed-bandwidth and fixed-delay guarantees.
D. WFQ can provide fixed-bandwidth guarantees.
E. WFQ prevents the large-volume flows with large packet size from starving out the low-volume flows with small packet size.
Answer: AE

4. For the following options, which of the following components of delay varies based on the varying sizes of packets sent through the network?
A. Codec delay
B. Serialization delay
C. Queuing delay
D. Propagation delay
Answer: B

5. As a candidate for CCVP exam, can you tell me what does a router base its opinion of how much bandwidth is available to a queuing tool on a serial interface?
A. The bandwidth command is required before a queuing tool knows how much bandwidth is available.
B. The automatically-sensed physical transmission rate on the serial interface.
C. The clock rate command is required before a queuing tool knows how much bandwidth is available.
D. Defaults to T1 speed, unless the bandwidth command has been configured.
Answer: D

6. Refer to the following parameters, which of the following are not traffic characteristics that can be affected by QoS tools?
A. Delay
B. MTU
C. Reliability
D. Bandwidth
Answer: C

7. After learning QoS, for the following options, Which of the following characterize problems that could occur with voice traffic when QoS is not applied in a network?(choose two)
A. Voice sounds choppy.
B. Calls are disconnected.
C. VoIP broadcasts increase as Queuing delay increases, causing delay and caller interaction problems.
D. Voice call requires more bandwidth as lost packets are retransmitted.
Answer: AB

8. Which statement best describes the peer-to-peer traffic (Napster and Kazaa2) going out on the interface s0/0 on the SF router?
A. The peer-to-peer traffic is not classified by the policy-map test , therefore all peer-to-peer traffic will be dropped.
B. The peer-to-peer traffic will be classified into the class-default traffic class.
C. The peer-to-peer traffic will have a maximum bandwidth guarantee of 25 percent of the s0/0 link bandwidth.
D. The peer-to-peer traffic will be classified into p2p traffic class.
Answer: B