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

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Example Questions

Which is the preferred queuing method provided by Cisco IOS Software for a converged VoIP network? When the customer LAN is managed by the service provider and the network is oversubscribed, what is the best location for use of congestion avoidance mechanisms? Within a QoS policy-map configuration, one of the traffic classes is configured with the random detect dscp-based configuration command. What will that command accomplish? When the RFC 3270 Uniform mode is used, the PHB at the egress router is based on which of these? What are three benefits of IntServ and RSVP? (Choose three.) Which tool is best suited to provide incident management or trouble ticketing? Where do service providers apply policy when traffic is leaving the customer network? (Choose two.) The provider you work for supports a wide range of Cisco router models and Cisco IOS Software releases. You are in the process of moving to a SNMP-based tool to monitor QoS configurations and statistics. What are some of the challenges to this approach? Which Cisco IOS command will show a summary of probes? Which Cisco IOS command lists all traffic classifications? An MPLS VPN customer reports that the VoIP voice quality is very bad for calls across the MPLS VPN. What could be the problem? Which Cisco IOS IP SLA Probe would you select to identify bottlenecks in the network? What are two benefits of the DiffServ model? (Choose two.) What are three fundamental QoS mechanisms? (Choose three.) Which two match statements are correct in Cisco IOS Software? (Choose two.) 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 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? Which MQC capabilities are unique to Cisco IOS XR Software? When the RFC 3270 Short Pipe mode is used, the PHB at the egress router is based on which of these? You work for service provider that employs a four-class service provider QoS model (best effort, bronze, silver, gold). A customer recently reported an issue with high drop rate on a missioncritical database application in the silver class. The silver class is currently at capacity. The gold class is currently only used for voice and video conferencing, and has available bandwidth. The application was remapped to the gold class. Which statements are valid alternative options to this decision? (Choose two.) Which three can be monitored by IP SLA? (Choose three.) A customer with an unmanaged CE router has reported experiencing poor quality on the video conferencing and broadcast multimedia applications. To address the issue, the provider has implemented shaping on the PE router to "smooth out" speed mismatches in the network. Which of these is a valid concern with this approach? Which statement about the MQC configuration shown here for the class-default traffic class is true? policy-map CE-EDGE-4CLASS-OC3-POS-1 class class-default bandwidth percent 25 ! When troubleshooting a QoS problem, which two key statistics should you look for? (Choose two.) When is a best-effort QoS policy most appropriate? What are the benefits of using differentiated services in the service provider backbone? (Choose two.) What three statements about WRED are true? (Choose three.) Which two methods can be used to monitor QoS performance? (Choose two.) A service provider recently changed from RFC 3270 Uniform mode to Pipe mode. Which three considerations about this change are true? (Choose three.) Which statement about the rates and statistics (such as match, transmit, drop, and police) shown in the show policy-map interface output is true? A customer reports that during peak hours, FTP performance is unacceptable. Currently, the service provider maps the customer FTP traffic into the class-default traffic class and FTP traffic is marked with MPLS EXP1. The class-default class traffic is configured with MPLS EXP based WRED and also with the bandwidth command. What could be causing the FTP performance issues with the customer? What problem could occur when applying this policy map on CE? policy-map CE-SP-MODEL class VOIP priority class BROADCAST-VIDEO priority class SP-CRITICAL-DATA bandwidth percent 40 random-detect exp 3 15000 packets 45000 packets class class-default random-detect exp 1 2500 packets 7500 packets random-detect exp 0 1500 packets 10500 packets A MPLS VPN customer reports poor VoIP call quality across the MPLS VPN. What could be the problem? Where would a service provider apply this policy? Which three components would you use to define and apply traffic classification? (Choose three.) To classify and prioritize traffic according to importance, which three statements are correct? (Choose three.) What would be the first step when defining an MQC? Which of these correctly describes traffic classification using qos-group? Which statement about when you mix TCP and UDP traffic in the same class and overflow occurs is true? Where would you apply WRED to avoid congestion and poor QoS from oversubscription of the network? An MPLS VPN customer with managed CE services recently made some changes to their call manager configurations. Now the customer reports that their VoIP traffic voice quality is very poor. What could be a cause of the problem? Which two items can be obtained from the CISCO-NETFLOW-MIB? (Choose two.) A customer is experiencing poor quality on voice connections coming from a particular branch office. Data on the service provider network capacity indicates that the devices serving that location are heavily oversubscribed. It will be months before planned expansions can be implemented. Which class-based traffic-shaping technique would be appropriate to consider implementing? A service provider will apply this policy at which of these interfaces? interface Gi1/1 service-policy output SP-POLICY ! policy-map SP-POLICY class TRAFFIC-CLASS-1 police rate percent 20 conform-action transmit exceed-action drop priority ! class TRAFFIC-CLASS-2 bandwidth percent 50 queue-limit 800 ms random-detect exp 3 280 ms 490 ms ! class class-default queue-limit 500 ms random-detect exp 1 200 ms 350 ms random-detect exp 0 100 ms 200 ms ! end-policy-map ! class-map match-any TRAFFIC-CLASS-1 match dscp ipv4 45 ef cs6 match mpls experimental topmost 5 6 end-class-map ! class-map match-any TRAFFIC-CLASS-2 match dscp ipv4 cs2 af21 af23 af31 af32 af33 35 37 match mpls experimental topmost 3 end-class-map ! What can be used to provide read-only access to QoS configuration information and statistics from a network management station? Which two statements about IP SLA are correct? (Choose two.) Which Cisco IOS feature is used to enable the following class map configuration? class-map match-all test-cm match protocol gnutella file-transfer "*" A provider plans to use IP SLA to help diagnose future performance issues in their PE routers in the network. Which two should be considered by the provider? (Choose two.) Which three issues are important challenges for monitoring service quality in the SP core network? (Choose three.) Which of these describes Short Pipe mode in QoS for MPLS VPN service providers?