Cisco CCNA (200-301)Network AccessEasy
A network technician is configuring an EtherChannel using LACP between two Cisco Catalyst switches, SW1 and SW2. The technician wants to ensure that the EtherChannel forms only if both sides actively attempt to negotiate the channel. Both Gi0/1 and Gi0/2 on SW1 are intended to be part of this EtherChannel. Which LACP mode should be configured on the interfaces Gi0/1 and Gi0/2 of SW1?
- Aon
- Bpassive
- Cauto
- Dactive
Show answer & explanationAnswer & explanation
Correct answer: D. active
The 'active' LACP mode actively initiates negotiation with the other switch to form an EtherChannel. For the EtherChannel to form only if both sides actively negotiate, both sides must be in 'active' mode.
Why the other options are wrong
- A. The 'on' mode forces the interface into an EtherChannel without LACP negotiation, which is not the requirement.
- B. The 'passive' mode waits for the other side to initiate LACP negotiation, which would not meet the requirement of 'both sides actively attempt'.
- C. The 'auto' mode is for PAgP, not LACP.
LACP Active Mode
LACP 'active' mode actively initiates negotiation with the other device to form an EtherChannel. It sends LACP PDUs automatically.
- Actively seeks to form a channel.
- Will form a channel with 'active' or 'passive' remote modes.
- Required if both sides must actively negotiate.
Memory trick: A.P.O. - Active, Passive, On (and off for EtherChannel)