4.5 Implement QoS Services 350-501 Practice Questions (Page 1)

Questions 1–5

1. 1expert · hard

   A service provider is troubleshooting packet loss on a core router link. The engineer discovers that WRED is configured, but voice traffic (DSCP EF) is being dropped more frequently than expected. The engineer also notices that the queue is frequently full, causing tail drops. The engineer needs to reduce voice drops while maintaining congestion avoidance for other traffic. Which configuration change should be made?

   • ADecrease the WRED drop threshold for DSCP EF to drop voice traffic earlier
   • BDecrease the queue limit to force earlier WRED drops
   • CDisable WRED and use tail drop instead
   • DIncrease the WRED drop threshold for DSCP EF and increase the queue limit
   Reveal Solution Discussion Select an answer first
2. 2expert · hard

   A service provider is designing QoS for a customer's internet access service. The customer has two requirements: (1) voice traffic must be strictly limited to 2 Mbps with any excess dropped to prevent voice quality degradation, and (2) data traffic should be smoothed to a maximum of 10 Mbps to avoid bursts overwhelming the customer's own router. The engineer must choose between policing and shaping for each traffic type. Which combination is correct?

   • AShape voice traffic at 2 Mbps; police data traffic at 10 Mbps with drop exceed-action
   • BPolice both voice and data traffic at their respective rates
   • CPolice voice traffic at 2 Mbps with drop exceed-action; shape data traffic at 10 Mbps
   • DShape both voice and data traffic at their respective rates
   Reveal Solution Discussion Select an answer first
4. 3foundation · easy

   What is the primary difference between traffic shaping and traffic policing?

   • AShaping drops packets, while policing buffers them
   • BShaping uses a token bucket, while policing does not
   • CShaping buffers excess traffic, while policing drops or marks excess traffic
   • DShaping is used only on ingress, while policing is used only on egress
   Reveal Solution Discussion Select an answer first
5. 4expert · hard

   A service provider is designing QoS for a customer's MPLS VPN service. The customer has two requirements: (1) critical data traffic must be strictly limited to 5 Mbps with excess dropped to prevent congestion on the customer's own network, and (2) bulk data traffic should be smoothed to a maximum of 20 Mbps to avoid bursts overwhelming the provider's PE router. The engineer must choose between policing and shaping for each traffic type. Which combination is correct?

   • AShape critical data at 5 Mbps; police bulk data at 20 Mbps with drop exceed-action
   • BShape both critical and bulk data at their respective rates
   • CPolice both critical and bulk data at their respective rates
   • DPolice critical data at 5 Mbps with drop exceed-action; shape bulk data at 20 Mbps
   Reveal Solution Discussion Select an answer first
6. 5foundation · easy

   What is the primary purpose of QoS classification and marking in a service provider network?

   • ATo encrypt packets to protect them from unauthorized inspection
   • BTo replace the need for access control lists by automatically prioritizing all traffic
   • CTo increase the bandwidth available to all traffic by compressing packet headers
   • DTo identify and label packets so that they can receive differentiated treatment throughout the network
   Reveal Solution Discussion Select an answer first