In the context of hierarchical scheduling, a scheduler is configured with a CIR weight of 0. Which of the following statements is TRUE?

Question

Options

• AThe scheduler will be allocated its "within CIR" bandwidth before all other children at the same
• BThe scheduler will be allocated its "within CIR" bandwidth after all other children at the same level
• CThe scheduler will be allocated its "within CIR" bandwidth after all other children at all levels have
• DThe scheduler will not be allocated its "within CIR" bandwidth.

• C
  4% (1)
• D
  96% (25)

Explanation

A CIR weight of 0 explicitly removes a scheduler from the committed information rate distribution entirely - zero weight means zero share, so no "within CIR" bandwidth is ever allocated to it (D). This is distinct from simply having a low priority; the scheduler is completely excluded from the CIR pool, not merely deprioritized.

Why the distractors fail:

• A is wrong because priority ordering (first/last) only applies to schedulers that actually participate in CIR allocation - weight 0 disqualifies the scheduler from the process altogether.
• B is wrong for the same reason; being served "last" still implies receiving some CIR bandwidth, which a weight-0 scheduler never does.
• C is the most tempting distractor - it sounds like a lowest-priority fallback - but again, weight 0 is not "lowest priority," it is no participation, not even after all other levels are served.

Memory tip: Think of CIR weight as a slice of a pie. A weight of 0 means you ordered no slices - not the smallest slice, not the last slice - you simply get nothing from that pie.

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