N10-009 Network Implementation Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Passive

  Why this is correct

  LACP passive mode enables an interface to listen for LACP Data Units (LACPDUs) from a peer and then respond to form a Link Aggregation Group (LAG). While it does not actively initiate LACP negotiation, it will successfully establish a bundled link with an LACP active port, which is constantly sending LACPDUs to discover and form a LAG. This complementary behavior ensures the two switches can dynamically agree on the aggregated links.

• ✗

  On

  Why it's wrong here

  The 'on' mode, also known as manual or static mode, forces an interface into a Link Aggregation Group (LAG) without using any negotiation protocol like LACP. In this configuration, the switch assumes the peer is also configured in 'on' mode, and no LACP Data Units (LACPDUs) are sent or processed. Consequently, an 'on' mode port cannot form a LAG with an LACP active port because the active port expects to receive and respond to LACP negotiation packets, which the 'on' port neither sends nor understands.

  When this WOULD be correct

  This option would be correct in a scenario where both switches are configured with static LAG (no LACP), such as when using a proprietary or static link aggregation that does not require protocol negotiation. For example, a question asking 'Which mode should be used on both switches for a static LAG without LACP?' would have 'On' as the correct answer.

• ✗

  Static

  Why it's wrong here

  "Static" is not a specific operational mode within the Link Aggregation Control Protocol (LACP) standard (802.3ad). While it is often used colloquially to describe a manually configured Link Aggregation Group (LAG) without LACP, the correct term for such a configuration is typically "on" mode or "manual" mode. Since LACP active ports require dynamic negotiation, a "static" or "on" configuration on the peer will prevent the formation of an LACP-controlled LAG due to the absence of protocol communication.

  When this WOULD be correct

  A question that asks: 'A network engineer wants to configure a static LAG without LACP between two switches. Which mode should be configured on both switches?' In that case, 'static' (or 'on') would be correct because no LACP negotiation is used.

• ✗

  Auto

  Why it's wrong here

  The 'auto' mode is a proprietary setting associated with Cisco's Port Aggregation Protocol (PAgP), not the industry-standard Link Aggregation Control Protocol (LACP). PAgP is a distinct protocol designed for aggregating Ethernet links on Cisco devices. An interface configured in PAgP 'auto' mode will only attempt to form a bundle with a peer configured in PAgP 'desirable' mode, and it will not recognize or respond to LACP Data Units (LACPDUs) from an LACP active port, making negotiation impossible.

  When this WOULD be correct

  In a Cisco PAgP (Port Aggregation Protocol) scenario, if one switch is set to 'Desirable', the other switch can be set to 'Auto' to form an EtherChannel. This question would be about PAgP, not LACP.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

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