EtherChannel LACP Passive Mode Configuration

200-301 By islever Editorial Last updated

Configure and verify (Layer 2/Layer 3) EtherChannel (LACP)

Short answer

A Passive mode enables LACP only if a LACP device is detected on the link.

Question

When configuring an EtherChannel bundle, which mode enables LACP only if a LACP device is detected?
  1. Passive Correct Answer
  2. Desirable
  3. On
  4. Auto
  5. Active

Key Takeaways

The exam often uses exact CLI help text wording; recognizing that 'Passive' waits for negotiation while 'Active' initiates it is key to answering correctly.

This question tests the specific behavior of Cisco EtherChannel modes, identifying that 'Passive' mode enables LACP only when an LACP device is detected on the remote end.

Common mistake: Candidates frequently select 'Active' because they associate 'enabling' a protocol with active initiation, missing the critical condition 'only if... detected' which implies a reactive stance.

Expert Analysis

Why the Answer Is Correct

The correct answer is A (Passive). The command output from the Cisco IOS CLI explicitly states: 'passive Enable LACP only if a LACP device is detected'. This mode will not send LACP packets but will respond to them, forming a bundle only when the neighbor is in Active or Passive mode.

Why the Other Options Are Wrong

Option E (Active) is incorrect because the CLI description for Active is 'Enable LACP unconditionally', meaning it actively sends negotiation packets regardless of what is detected. Option D (Auto) and B (Desirable) are PAgP modes, not LACP. Option C (On) forces the channel without any negotiation protocol.

Community Comment Notes

Community members like hokieman91 and LKPN correctly identified 'Passive' by referencing the exact switch explanation text. While some users initially debated between Active and Passive due to the wording, the verbatim CLI help confirms Passive is the precise match for the scenario described.

Exam Strategy

Memorize the exact descriptions provided in the 'channel-group mode ?' CLI help for both PAgP and LACP options, as exams frequently quote these directly.

Frequently Asked Questions

Why is Active not the correct answer for enabling LACP?

Active enables LACP unconditionally by sending packets immediately. Passive waits until it detects LACP packets from the other side before enabling.

What is the difference between Auto and Passive modes?

Auto is used for PAgP (Cisco proprietary), while Passive is used for LACP (IEEE standard). They operate on different protocols.

More 200-301 FAQ →

Discussion 24 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 24

  1. hokieman91 👍 25
    "A" ---- Answer given is correct. Actually a good question since this verifies the knowledge of how LACP works - remember a channel in Passive "wants" to be part of a channel but will sit and wait and only bind if the other end is "Active". I think of "Passive" as follow the leader and "active" as the "do what I say" bully config.
  2. Joe_Q 👍 14
    enables LACP only if a LACP device is detected, keyword is here is "detected". Active does not detect, it is always sending out LACP negotiation messages. Passive is always detecting, waiting for a negotiation message.
  3. ProgSnob 👍 10
    The wording is a bit obfuscating. I keep rereading it and feeling like depending on how you perceive the wording, both A and E could be correct.
  4. bobert 👍 8
    "Active" implies actively negotiating state. A Passive interface will not enable LACP if the other end is also Passive (LACP) .. So only an Active interface will enable LACP if either Active or Passive LACP interface is connected
  5. Ciscoman021 👍 5
    you are not alone. :)
Show 19 more comments
  1. ZUMY 👍 5
    A is correct
  2. LKPN 👍 4 Answered A
    From Packet Tracer Switch(config-if-range)#channel-group 1 mode ? active Enable LACP unconditionally auto Enable PAgP only if a PAgP device is detected desirable Enable PAgP unconditionally on Enable Etherchannel only passive Enable LACP only if a LACP device is detected
  3. asd34534 👍 3
    Switch(config-if-range)#channel-group 1 mode ? active Enable LACP unconditionally auto Enable PAgP only if a PAgP device is detected desirable Enable PAgP unconditionally on Enable Etherchannel only passive Enable LACP only if a LACP device is detected the question is taken from the switch explanation above i think the answer should me active but i will go with passive
  4. dave1992 👍 3
    lets say the other side is either active or passive. doesnt matter, but putting the opposite side as Active will always make the etherchannel. (as long as the other side is active or passive) active is the best answer.
  5. Zerotime0 👍 3
    Not clear question to me. Wouldnt it be active? Then thats how it will actively search out another lacp enabled device? If its passive its not active in search for one... can some one chime in on this ?
  6. Taps 👍 3
    The word passive means the opposite: That it has found a connection and its up and ready. Active is also the opposite: It doesn't have a connection and so its not looking for one.
  7. admin1982 👍 3
    The correct answer should be E..."Active"
  8. Zerotime0 👍 3
    Good clarity
  9. Elmasquentona963 👍 2
    Sorry, I found this from Wikkipedia and Cisco-Press. I think the last source was was a typo from Cisco. LACP mode : Active: Enables LACP unconditionally. Passive: Enables LACP only when an LACP device is detected. (This is the default state) Correct Answer is "A".
  10. Bhrino 👍 2 Answered A
    I think the wording of the question is weird but the reason it’s passive is because the question ask which mode will only activate lacp if it dectects lacp which is passive. Passive in a way listens to what it’s being told
  11. LilGhost_404 👍 2
    The question is not really clear. The next question will be how a LACP device is detected? Is it because the remote device sent a LACPdu? Or the local device sent it and the remote respond it?
  12. Hodicek 👍 2
    LACP ACTIVE PASSIVE, IN THE QUESTION ONE IS DETECTED SO IT IS ACTIVE SO OTHER SHOULD BE PASSIVE
  13. ismatdmour 👍 2 Answered A
    passive Enable LACP only if a LACP device is detected. This is how the passive is described
  14. sdokmak 👍 2
    I also thought same as you but yeah it is "Passive", Joe_Q's explanation was pretty good.
  15. gc999 👍 2
    Agree. I set the mode to "Active", so it can "detected" the other end.
  16. bobert 👍 2
    correction ... read again and A is correct
  17. johnnd 👍 1
    LACP packets are exchanged between ports in these modes: •Active—Places a port into an active negotiating state, in which the port initiates negotiations with remote ports by sending LACP packets. •Passive—Places a port into a passive negotiating state, in which the port responds to LACP packets it receives but does not initiate LACP negotiation. In this mode, the port channel group attaches the interface to the bundle. https://www.cisco.com/c/en/us/td/docs/ios/12_2sb/feature/guide/gigeth.html
  18. Elmasquentona963 👍 1 Answered E
    "active —Enables LACP only if a LACP device is detected." Source: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-6/configuration_guide/b_166_lyr2_lyr3_9500_cg/b_166_lyr2_lyr3_9500_cg_chapter_011.html#concept_4685AEC0AD9E4DBFA49AEE35D3B4A028:~:text=with%20Auto%2DLAG-,Configuring%20Layer%C2%A02%20EtherChannels%20(CLI),-You%20configure%20Layer
  19. maximus_007 👍 1 Answered A
    The key word that the question is missing is that it is not asking for the LACP config to initiate the negotiation (active), hence why A is the correct answer.

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