Which of the following descriptions of link aggregation in LACP mode is correct?

Question

Options

• AIn LACP mode, the devices at both ends of the link send LACP messages to each other.
• BThe number of active ports cannot be set in LACP mode.
• CIn LACP mode, all active interfaces participate in data forwarding and share load traffic.
• DThere are only a maximum of 4 active ports in LACP mode.

• A
  74% (14)
• B
  5% (1)
• C
  16% (3)
• D
  5% (1)

Explanation

Option A is correct because LACP (Link Aggregation Control Protocol) is a signaling protocol by design - both ends of a link must continuously exchange LACP PDUs (protocol data units) to negotiate, establish, and maintain the aggregated link bundle; this bidirectional communication is the defining characteristic that separates LACP mode from static (manual) aggregation.

Option B is wrong because LACP does allow you to configure the maximum number of active ports in the bundle, with any remaining ports held in standby ready to take over if an active port fails. Option C is wrong because standby ports exist in LACP mode precisely to provide redundancy - they do not forward data unless promoted to active, so not all member interfaces participate in forwarding at the same time. Option D is wrong because the IEEE 802.3ad/802.1AX standard supports up to 8 active ports per aggregation group (plus up to 8 standby ports), making the "maximum of 4" claim incorrect.

Memory tip: LACP has "Control Protocol" in its name - control protocols always involve two-way message exchange between peers, which is exactly what option A describes.

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