When using an egress port scheduler, on which scheduling loop are orphaned queues serviced?

Question

Options

• ALevel 8 within CIR.
• BLevel 8 between CIR and PIR.
• CLevel 8, once all PIR is serviced.
• DLevel 1 within CIR.
• ELevel 1 between CIR and PIR.
• FLevel 1, once all PIR is serviced.

• B
  9% (3)
• C
  78% (25)
• D
  3% (1)
• E
  3% (1)
• F
  6% (2)

Explanation

Orphaned queues - those whose parent scheduler no longer exists in the applied policy - are treated as "best-effort leftovers" and are therefore serviced at the very end of the scheduling process: Level 8, only after all PIR for properly configured queues has been satisfied (option C). This placement ensures that misconfigured or detached queues cannot steal committed or peak-rate bandwidth from legitimate flows.

Options A and B are wrong because orphaned queues are explicitly excluded from the CIR and CIR-to-PIR loops; they carry no rate guarantee and cannot compete during those phases. Options D, E, and F are wrong on the level number - Level 1 is the highest-priority scheduling level, which would be the opposite of the intent; orphaned queues belong at Level 8, the lowest priority. Option F gets the phase right (post-PIR) but uses the wrong level number.

Memory tip: Think of orphaned queues as "orphans eating last at the table" - they wait until every other guest (all CIR, then all PIR) has finished before touching the remaining scraps, and they sit at the far end (Level 8, not Level 1).

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