Question

Difficulty: MediumLayer 2 and Layer 3 EtherChannel (LACP)

A network engineer is configuring a routed (Layer 3) EtherChannel between Switch-1 and Switch-2 using the Link Aggregation Control Protocol (LACP). On Switch-1, the engineer creates `interface Port-channel 5`, configures `no switchport`, and assigns an IP address. On physical interfaces GigabitEthernet0/1 and GigabitEthernet0/2, the engineer enters `no switchport` and `channel-group 5 mode passive`.

Which combination of commands must be configured on Switch-2 for the routed EtherChannel to successfully form and exchange LACP frames?

  1. Configure 'no switchport' on interface Port-channel 5 and both physical member interfaces, and set 'channel-group 5 mode active' on the physical interfaces.Answer
  2. B
    Configure 'no switchport' on interface Port-channel 5 and set 'channel-group 5 mode passive' on both physical member interfaces.
  3. C
    Configure 'channel-group 5 mode desirable' on the physical interfaces and enable 'switchport mode trunk' on interface Port-channel 5.
  4. D
    Configure 'no switchport' and assign individual IP addresses directly to physical interfaces GigabitEthernet0/1 and GigabitEthernet0/2, then set 'channel-group 5 mode active'.

Answer

Configure 'no switchport' on interface Port-channel 5 and both physical member interfaces, and set 'channel-group 5 mode active' on the physical interfaces.
To establish an LACP EtherChannel bundle when Switch-1 is configured in passive mode, Switch-2 must be set to active mode so it actively sends LACP negotiation frames. Additionally, converting an EtherChannel to Layer 3 requires disabling switchport features using 'no switchport' on both the logical port-channel and the physical member interfaces.

Step-by-Step Solution

1
Analyze the LACP negotiation mode requirement
Switch-1 is set to LACP passive mode, which only responds to LACP requests but does not initiate them.
For LACP to negotiate a bundle, at least one peer must be configured in active mode (Active-Passive or Active-Active).
2
Verify Layer 3 EtherChannel interface requirements
Both the logical Port-channel interface and physical member interfaces must be routed ports ('no switchport').
Layer 3 EtherChannels require consistent routed port configuration across the bundle, with IP addressing applied strictly to the logical Port-channel interface.

Key Concept

Layer 3 EtherChannel LACP Negotiation and CLI Configuration Requirements
Rate this question