Which of the following statements BEST defines policing?

Question

Options

• AThe process of delaying packets within a traffic stream to have them conform to a defined traffic
• BThe overall treatment of a defined subset of a customer's traffic within a DiffServ domain.
• CThe process of discarding packets within a traffic stream in accordance with the state of a meter
• DThe action of setting the DiffServ codepoint of a packet prior to its entry into a downstream
• EA specified algorithm or operation that is implemented in a node in order to realize one or more

• B
  7% (2)
• C
  89% (25)
• D
  4% (1)

Explanation

Policing is specifically the act of enforcing a traffic contract by discarding non-conforming packets - a meter measures the incoming rate, and packets that exceed the defined threshold are dropped (or sometimes re-marked). This makes C the precise, RFC-standard definition.

Why the distractors are wrong:

• A describes traffic shaping - shaping delays packets via buffering to smooth traffic, whereas policing drops them immediately.
• B describes a Per-Hop Behavior (PHB) - the aggregate treatment of a traffic class within a DiffServ domain, not a specific enforcement mechanism.
• D describes marking - writing a DSCP value into the packet header so downstream nodes know how to treat it.
• E describes a PHB scheduling algorithm or queuing mechanism - an operation in a node, not a policing action specifically.

Memory tip: Think "Police = Drop, Shape = Delay." A police officer stops a speeder (drops the packet); a traffic cone slows you down (delays/buffers the packet). If the answer involves buffering or smoothing, it's shaping - if it involves meters and discards, it's policing.

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