Examkin

Question

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

A network administrator is configuring QoS mechanisms on a branch router edge interface to manage traffic bursts that periodically exceed the committed contract rate. Which two statements accurately describe the operational characteristics of traffic shaping?

  1. Buffers excess packets in a queue and delays their transmission to smooth the outbound traffic flow.Answer
  2. Can only be implemented in the egress direction on a network interface.Answer
  3. C
    Immediately drops out-of-profile packets as soon as the traffic rate exceeds the burst threshold.
  4. D
    Remarks out-of-profile traffic to a lower precedence value instead of delaying packet egress.

Answer

Traffic shaping buffers excess packets in a queue to release them smoothly over time, and it can only be configured in the egress direction on an interface.
Traffic shaping is designed to smooth egress traffic rates by holding non-conforming packets in software queues and transmitting them as bandwidth becomes available. Because this queueing and scheduling process takes place before sending packets out of an interface, shaping is strictly an egress-only feature.

Step-by-Step Solution

1
Analyze the core operational mechanism of traffic shaping.
Traffic shaping retains packets in a queue when the traffic rate exceeds the configured rate (CIR) and transmits them gradually to achieve a regulated flow.
Understanding the role of internal buffers differentiates shaping from policing.
2
Determine the interface direction constraints for traffic shaping.
Since packets must enter an egress queue before being delayed and scheduled for transmission, shaping can only be applied in the egress direction.
Ingress interfaces cannot hold packets in an egress scheduling buffer.
3
Differentiate policing functions from shaping functions to rule out incorrect choices.
Actions such as dropping excess packets immediately or remarking packet header fields are characteristic of policing, which does not buffer traffic.
Policers handle traffic bursts by dropping or remarking rather than queueing.

Key Concept

Traffic Shaping vs. Traffic Policing Mechanisms
Estimated Time:1m 0s
Rate this question

Topics

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

More questions from this topic