liveBook · Manning

Passive mode

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

Passive mode is an LACP setting that responds to negotiation messages from an active-mode neighbor without initiating negotiation.

Passive mode is an LACP setting that waits for an active neighbor to initiate negotiation, then responds to LACP messages. It is useful when one side should listen rather than start the EtherChannel negotiation. section 16.2.1

Remember these LACP rules:

  • Active + passive forms an EtherChannel; passive + passive does not. section 16.2.1
  • Configure it with channel-group group-number mode passive in interface configuration mode. section 16.5
  • Use passive only with another LACP port; LACP cannot negotiate with PAgP or a static mode-on port. section 16.5

Active neighbor with a passive neighbor

On SW1, configure G0/0–1 with channel-group 1 mode active. On SW2, configure the same interfaces with channel-group 1 mode passive. Apply switchport mode trunk to each Po1. Verification with show etherchannel summary should show LACP and both physical ports bundled with P flags.

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

How deep it goes
Explains negotiation combinations, configuration syntax, compatibility limits, and verification, but not LACP internals.
Examples
Uses SW1 and SW2, paired GigabitEthernet interfaces, Port-channel1, and show etherchannel summary output.
What it assumes
Assumes basic EtherChannel and interface configuration knowledge while contrasting LACP with PAgP.
What you can do after
Apply passive mode through Cisco channel-group configuration and verify the resulting LACP bundle.
How it connects
Connects LACP with EtherChannel, active mode, PAgP, trunking, and static mode-on configuration.
Cover of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols
liveBookmanning.com
Read Acing the CCNA Exam: Volume 1 Fundamentals and Protocols on liveBook Get the book at manning.com

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols. The section links point to the parts of the book it draws on.