Which of the following are the minimum requirements needed to classify traffic marked with DSCP AF11, AF12, and AF13 into the AF forwarding class and provide fair treatment to the drop precedence…

Question

Options

• AProfile mode queues
• BPriority mode queues
• C1 queue
• D3 queues
• E3 forwarding classes
• F1 forwarding class, with 2 subclasses
• G1 forwarding class, with 3 subclasses

• A
  78% (31)
• B
  8% (3)
• D
  3% (1)
• E
  10% (4)
• G
  3% (1)

Explanation

AF11, AF12, and AF13 all share the same forwarding class (AF1x - the first digit = class, the second digit = drop precedence), so only 1 queue (C) and 1 forwarding class (F) are needed; the base forwarding class plus 2 subclasses yields exactly 3 drop-precedence buckets (low/medium/high) - not 3 subclasses (G), which would create 4 levels. Profile mode queues (A) are required because only profile mode can apply distinct drop profiles to subclasses within a single queue, enabling fair differential drop treatment; priority mode (B) is a scheduling mechanism between queues, not a within-queue drop-differentiation tool. Three queues (D) is wrong because subclasses handle the drop-precedence split inside one queue - no extra queues needed - and three forwarding classes (E) would only be correct if the traffic belonged to three different AF classes (e.g., AF11, AF21, AF31).

Memory tip: Read DSCP AF codes as AF-[Class][Drop] - same class digit = same single queue and forwarding class; count the drop variants (3 here), subtract 1 for the base class to get subclass count (2); and remember Profile mode = Precedence/drop treatment within a queue.

No community discussion yet for this question.