Examkin

Question

Difficulty: MediumQoS Per-Hop Behaviors, Classification, Marking, Queuing, and Traffic Shaping/Policing

An enterprise WAN edge router frequently transmits micro-bursts of database traffic that temporarily exceed the contract rate limit set by the service provider. The network engineer must implement a Quality of Service (QoS) mechanism on the egress WAN interface that regulates outbound transmission rates to match the provider's limit by holding excess packets in memory queues for later transmission rather than immediately dropping them. Which QoS mechanism should be configured on the router interface?

  1. Traffic ShapingAnswer
  2. B
    Traffic Policing
  3. C
    Weighted Random Early Detection (WRED)
  4. D
    Explicit Congestion Notification (ECN)

Answer

Traffic Shaping is the correct mechanism because it uses software queues to buffer excess traffic and smooth out rate bursts before sending packets across the egress link.
Traffic Shaping is a traffic conditioning mechanism applied in the egress direction that buffers excess packets in memory queues when traffic exceeds the configured Committed Information Rate (CIR). It slowly releases packets over time, creating a smooth output rate that prevents service provider packet drops.

Step-by-Step Solution

1
Analyze the operational requirements stated in the scenario.
The requirement demands regulating outbound WAN traffic to a target rate while buffering bursty traffic instead of dropping it.
Understanding the difference between packet dropping and packet buffering key behavior is critical for QoS traffic conditioning selection.
2
Compare Traffic Shaping and Traffic Policing operational characteristics.
Traffic Shaping buffers out-of-profile packets in memory queues, whereas Traffic Policing drops or remarks out-of-profile packets.
Buffering enables smoothing of bursty traffic flows at the cost of slight delay, fulfilling the exact requirement.

Key Concept

Traffic Shaping vs. Traffic Policing Mechanisms
Rate this question

Topics

QoS Per-Hop Behaviors, Classification, Marking, Queuing, and Traffic Shaping/Policing

More questions from this topic