Click the exhibit button below. Given the slope-policy (below), which of the following statements are TRUE? (Choose two)

Question

Exhibit

Options

• AAll out-of-profile traffic will be dropped before that of any in-profile traffic.
• BThe discard probability slope of an in-profile traffic is steeper than that of an out-of- profile traffic.
• CWhen the shared buffer utilization reaches 55%, both in-profile and out-of-profile packets may be
• DThe maximum probability with which an out-of-profile packet can be dropped is higher than that of
• EWhen the shared buffer utilization is at 61%, only in-profile packets are currently in the shared

• A
  8% (3)
• B
  13% (5)
• C
  74% (29)
• E
  5% (2)

Explanation

Slope Policy QoS Buffer Management

Options C and D are correct because slope policies use probabilistic dropping (similar to WRED) rather than absolute cutoffs. At 55% shared buffer utilization, both the in-profile and out-of-profile drop slopes have typically crossed their respective low-threshold trigger points, meaning packets from both traffic classes are subject to random early discard - hence "may be" dropped (C is true). Additionally, the out-of-profile slope is deliberately designed to reach a higher maximum drop probability (often 100%) than in-profile traffic (often ~75–80%), ensuring conforming traffic is preferentially protected over excess traffic (D is true).

Why the distractors are wrong:

• A is false because dropping is probabilistic, not sequential - you won't exhaust all out-of-profile packets before touching in-profile ones; both slopes operate concurrently.
• B is false because the out-of-profile slope is steeper, not the in-profile one - it rises faster to push excess traffic out more aggressively.
• E is false because high drop probability doesn't mean zero out-of-profile packets remain in the buffer; some still get through probabilistically until 100% drop is reached.

Memory tip: Think of slope policy as a "two-lane ramp" - the out-of-profile lane hits a tollbooth (drop) earlier and harder than the in-profile lane, but both lanes can have cars on them at the same time. "Higher max drop + earlier trigger = punish the overage, protect the contract."

No community discussion yet for this question.