642-642 - QOS - Quality of Service Exam

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Example Questions

QoS policy propagation through BGP (QPPB) supports which two QoS markers? (Choose two.) A Cisco Catalyst switch has an IP phone connected to its Fastethernet0/2 port. The IP phone has an attached PC. The Fastethernet0/2 port on the switch has been configured with the commands mls qos trust cos, mls qos trust device cisco-phone, and switchport priority extend trust. What will happen to a data frame with a CoS of 5 that is sent from the PC through the IP phone to port Fastethernet0/2 on the switch? In which two locations is the qos pre-classify command applied to support QoS preclassification over an IPSec/GRE tunnel? (Choose two.) What is the purpose of using multiactions traffic policing? What will happen when class-based header compression is configured without specifying RTP or TCP? For which service is assured forwarding PHB used? When LLQ is being configured, which IOS command is used to limit the traffic rate on the priority queue even when the other class queues are not congested? Based on the following 2950 switch configurations, which statement is correct? no wrr-queue cos-map wrr-queue bandwidth 20 10 70 1 wrr-queue cos-map 4 5 wrr-queue cos-map 1 0 1 2 3 wrr-queue cos-map 3 6 7 What describes the use of best-effort service with overprovisioning? Which statement is true about policing traffic conditioners in IP QoS? What is the recommended differentiated services code point (DSCP) value for scavenger traffic? At the network layer, IP packets are typically classified based on which three items? (Choose three.) You are the network administrator at . The newly appointed trainee wants to know in which configuration mode the following MQC command can be used. What will your reply be? match ip dscp af41? How does NBAR differ from traditional TCP/UDP packet recognition? Which statement regarding the policing traffic conditions in IP QoS is valid? What are two key advantages of the DiffServ model? (Choose two.) What does the term serialization delay refer to? When using Modular QoS CLI to classify packets arriving from a specific MAC address, which command should you use? Based on the following Cisco Catalyst 2950 Series switch configurations, which additional command will enable these actions? Traffic marked with a CoS of 6 or 7 will be serviced by the priority queue. Traffic marked with a CoS of 0, 1, or 2 will have a 20-percent weight when serviced by the wrr queue. Traffic marked with a CoS of 4 will have a 30-percent weight when serviced by the wrr queue. Traffic marked with a CoS of 3 or 5 will have a 50-percent weight when serviced by the wrr queue. Catalyst 2950 partial configuration: no wrr-queue cos-map wrr-queue cos-map 1 0 1 2 wrr-queue cos-map 2 4 wrr-queue cos-map 3 3 5 wrr-queue cos-map 4 6 7 Which 3 options may be used on Cisco Catalyst switches for classifying IP Packets? (Choose 3) Which one of the following configurations provides a maximum bandwidth guarantee of 192 kbps for the real-time traffic class? Which two components are associated with the DiffServ model? (Choose two.) In an unmanaged CE router implementation, how does the service provider enforce the SLA? Which of the following configurations requires the use of hierarchical policy maps? Which RED packet drop mode is used when the average queue size has reached or exceeded its maximum? Which mechanism is used by IP RTP Priority to classify packets? Switch port fa0/2 has been configured to connect an IP phone with an attached PC. Given the set of commands shown below, where does the trust boundary lie? interface fa0/2 mls qos trust cos mls qos trust device cisco-phone switchport voice vlan 112 What makes the DiffServ model more scalable than the IntServ model? (Choose all that apply.) What is the purpose of shaping traffic conditioners in IP QoS? What three actions can reduce packet sizes on WAN links supporting converged VoIP and data? (Choose three) Where is the error in the following policy-map configuration? policy-map test class voice priority 168 class mission-critical bandwidth 192 random-detect class class-default fair-queue bandwidth 128 Which of the following statements about NBAR is true? Which command is needed to correct the following configurations in order to enable ppp multilink LFI on the s0/0 interface? interface Serial0/0 ip address encapsulation ppp no fair-queue ppp multilink multilink-group 2001100114 ! interface Multilink2001100114 bandwidth 384 ip address service-policy output AutoQoS-Policy-UnTrust ppp multilink ppp multilink fragment-delay 10 ppp multilink interleave Traffic classification using NBAR is configured using which IOS command? Which configuration command applies QoS features to a particular traffic class? According to the best practices, in a service provider network, which statement is true as related to the QoS policy that should be implemented on the inbound provider (P) to provider (P) router link? Auto QoS is which type of Cisco IOS command? The following commands have been configured under the fa0/1 interface on the 2950 switch: wrr-queue bandwidth 20 1 80 0 mls qos trust cos mls qos trust device cisco-phone Voice traffic from the IP phone that is directly connected to the fa0/1 interface is experiencing excessive delays. What could be the cause of this problem? Which binary pattern is a valid class selector PHB DSCP value? Based on the configuration, which two of the following statements are true? (Choose two.) policy-map police 1 class bulk-ftp police cir percent 20 pir percent 40 conform-action set-dscp-transmit af11 exceed-action set-dscp-transmit 0 violate-action drop What is a key benefit of using the Cisco Modular QoS Command Line Interface (MQC)? The QoS pre-classify feature is used to ensure QoS services operate in conjunction with which two networking technologies? (Choose two) What does the service-policy statement do? What is the default match strategy for a class map? Within a distributed call processing environment, what can you use to achieve call admission control across the WAN? What are two common problems for video in the absence of QoS? (Choose two) You are the network administrator at . The newly appointed trainee wants to know which dial-peer subcommand correctly performs marking of VoIP packets. What will your response be? When configuring Priority Queuing on Cisco IOS routers, which three steps are required? (Choose three) The QoS design and implementation process comprises of the following steps: 1. characterize network 2. implement policy 3. determine customer priorities/QoS policy 4. monitor network What is the correct order for these steps? What are three reasons link efficiency mechanisms are deployed on WAN links? (Choose three.)