Which statement about the AOS-CX VOQ feature is true?

Question

Options

• AIt enhances local prioritization of datagrams marked with priority code points
• BIt provides ingress buffers with queues for each egress port to reduce risk of dropped packets
• CIt optimizes LACP uplinks that connect to multi-chassis VSX LAGs
• DIt dynamically allocates extra buffer space to egress queues to reduce the potential of dropped

• B
  95% (38)
• C
  3% (1)
• D
  3% (1)

Explanation

VOQ (Virtual Output Queuing) works by creating separate ingress-side buffer queues for each egress port on the switch. This is the defining characteristic of the feature - Option B is correct because it accurately describes VOQ holding traffic at the ingress, sorted by destination egress port, which eliminates head-of-line blocking and significantly reduces drops when one output port is congested.

Why the distractors are wrong:

• A describes QoS behavior related to Priority Code Points (PCP/CoS markings) - that's standard queue scheduling (e.g., strict priority or WRR), not VOQ.
• C describes VSX/LACP behavior for multi-chassis link aggregation - a separate high-availability feature unrelated to buffer management.
• D describes dynamic buffer allocation (sometimes called shared or elastic buffering), which adds buffer space to egress queues on demand - the opposite side of the switch from where VOQ operates, and a different mechanism entirely.

Memory tip: The name is the trap - "Virtual Output Queue" sounds like it's on the egress side, but VOQ queues live at the ingress, pre-sorted by their destination output port. Think: "Output in name, Input in location."

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