Maintaining Cisco Service Provider Quality of Service (MSPQS)

Question 1

A customer reports drops for traffic in the BIZ-CRITICAL class. As part of the verification process you identify that there is a high number of random drops. Which of these can help address this problem?

A. Decrease the queue limit for the traffic class.

B. Decrease the WRED drop probability denominator for the class.

C. Enable fair queuing for the BIZ-CRITICAL class.

D. Increase the WRED min threshold value for the traffic class.

Correct Answer: D

Question 2

Which three match statements are valid in Cisco IOS XR Software? (Choose three.)

A. match qos-group

B. match mpls experimental topmost

C. match port-type

D. match field

E. match flow

F. match vpls

Correct Answer: A,B,F

Question 3

Which three issues are important challenges for monitoring service quality in the SP core network? (Choose three.)

A. Packets have to traverse many network devices and links that add up to the overall delay.

B. Multiple flows compete for a limited amount of bandwidth.

C. Relatively few tools are available for collecting service quality data.

D. Traffic flows are continuously high.

E. Packets may have to be dropped when a link is congested.

Correct Answer: A,B,E

Question 4

Refer to the exhibit.

Which two statements are correct? (Choose two.)

A. This example is a hierarchical MQC example, and the cust-policy is the child policy.

B. Within the cust2-classes policy, the gold class is guaranteed 30 percent of the S3/2 interface bandwidth. Silver is guaranteed 15 percent of the S3/2 interface bandwidth. Bronze is guaranteed 10 percent of the S3/2 interface bandwidth.

C. This example queues the traffic into different CBWFQ classes before the aggregate traffic is shaped.

D. The policy map cust-policy specifies an average traffic shaping rate of 384 kb/s for the cust1 class and assigns the service policy cust1-classes to the cust1 class.

E. Within the cust1-classes policy, the gold class is guaranteed 50 percent of the bandwidth. Silver is guaranteed 20 percent of the bandwidth, and bronze is guaranteed 15 percent of the bandwidth.

F. The traffic class cust2 is ensured a bandwidth of 51.2 kb/s.

Correct Answer: D,E

Question 5

Refer to the exhibit.

A service provider moved from a three-class service provider QoS model to a four-class service provider QoS model. A new class of service called CRITICAL-B was created to support traffic with a DSCP marking of AF31. A customer reports that the traffic in the CRITICAL-B class is having problems. What step should the service provider take to correct this issue?

A. The policy map should be updated to move the BULK class to the bottom of the policy.

B. The CRITICAL-A class should change from match-all to match-any.

C. The class map for CRITICAL-B should have a DSCP value of 28.

D. The max-reserved-bandwidth command must be used to allocate more bandwidth than allowed by default.

Correct Answer: A

Question 6

Which two statements about IP SLA are correct? (Choose two.)

A. IOS IP SLA is a traffic monitoring mechanism that gathers statistics about traffic based on packet headers and fields.

B. IOS IP SLA uses active traffic monitoring which allows users to analyze service levels for IP applications.

C. Cisco IOS IP SLA is Layer 2 transport independent.

D. IP SLA uses NBAR to provide the reporting engine for statistics that it collects.

E. Cisco IOS IP SLA can be used to help detail billing information for each defined class of service.

Correct Answer: B,C

Question 7

Refer to the exhibit.

A provider uses the recommended mappings for DSCP to MPLS EXP. Several sites connected to the same PE router report that critical data has been experiencing a high number of drops. The customer marks its CRITICAL data as AF31. What appears to be the problem?

A. The classification for CRITICAL-DATA should contain a match-all, not a match-any.

B. The allocated bandwidth for CRITICAL-DATA should be increased to provide sufficient bandwidth to support the application.

C. If the data receiving drops is high priority, it should be marked with MPLS EXP value 7.

D. The recommended mapping for AF31 is to MPLS EXP 5, which is classified in the REALTIME class, not the CRITICAL DATA class.

E. The provider is using the recommended mappings for DSCP to MPLS EXP, so the CLASS-MAP for the CRITICAL-DATA should contain EXP value of 4.

Correct Answer: E

Question 8

A customer reports that the packets from their custom TCP application, which is currently marked as DSCP AF43, is being dropped more frequently than desired. All of the links in service provider network are using DSCP-based WRED. What can be changed to best improve the drop rate of the customer's custom application without causing major problems for the other traffic classes?

A. Mark the custom application traffic to DSCP AF41 instead.

B. Remove WRED on all the links.

C. Use a different queuing method for the AF43 traffic class.

D. Allocate more bandwidth to the AF43 traffic class.

E. Mark the custom application traffic to DSCP EF instead.

Correct Answer: A

Question 9

Which four factors can be used for packet classification in a QoS-aware network device? (Choose four.)

A. MQC

B. DSCP

C. destination address

D. TTL

E. IP precedence

F. source address

Correct Answer: B,C,E,F

Question 10

Which three can be monitored by IP SLA? (Choose three.)

A. queue utilization

B. buffer allocation

C. network delay

D. jitter

E. packet loss

Correct Answer: C,D,E

Cisco Maintaining Cisco Service Provider Quality of Service (MSPQS) - 642-785 Exam Practice Test

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