Examkin

Question

Difficulty: MediumWLAN Infrastructure Connections and LAG

A network administrator is connecting a Cisco Catalyst 9800 Series Wireless LAN Controller to an upstream Cisco Catalyst switch using link aggregation (LAG) with LACP. In what logical order should the administrator execute the steps on the Catalyst switch to provision the EtherChannel interface and physical member ports?

  1. 1Create the logical port-channel interface in global configuration mode.
  2. 2Configure 802.1Q trunking, native VLAN, and allowed VLAN parameters directly on the logical port-channel interface.
  3. 3Enter interface range mode to select the physical switch interfaces connecting to the controller distribution system ports.
  4. 4Assign the selected physical interfaces to the channel group using LACP active mode.
  5. 5Execute the 'show etherchannel summary' command to verify operational status and member port state.

Answer

The correct sequence begins with creating the logical port-channel interface on the switch, applying trunking and VLAN parameters to that logical interface, selecting the physical member interfaces, adding the physical interfaces to the EtherChannel using active LACP mode, and finally verifying bundle operation with the 'show etherchannel summary' command.
To establish link aggregation between a Cisco Catalyst switch and a Cisco Wireless LAN Controller using LACP, standard configuration methodology requires initializing the logical port-channel interface first. Trunking settings (such as switchport mode trunk and VLAN assignments) are defined on the logical port-channel. Next, the target physical member interfaces are selected and bound to the channel group using active LACP mode. Finally, running operational verification commands confirms proper link aggregation state.

Step-by-Step Solution

1
Create the virtual port-channel interface
The logical interface Port-channel 1 is initialized.
Creating the logical interface first provides the administrative entity where trunking parameters will be defined.
2
Configure trunking properties on the port-channel
The port-channel interface is set to switchport mode trunk with explicit native and allowed VLAN parameters.
Defining trunk settings directly on the port-channel interface guarantees uniform configuration for all associated physical ports.
3
Select physical switch interfaces
The physical ports connected to the wireless controller are selected via interface range configuration mode.
Grouping physical interfaces prepares them for enrollment into the EtherChannel bundle.
4
Bind physical ports to the channel group using LACP
The command 'channel-group 1 mode active' enables dynamic LACP negotiation on the physical ports.
LACP active mode allows the switch to initiate negotiation with the Wireless LAN Controller.
5
Verify EtherChannel operation
Output displays flag 'SU' for the port-channel and flag 'P' for each active member port.
Verifying status confirms that LACP negotiation succeeded and traffic can be forwarded across the aggregated links.

Key Concept

Cisco switch EtherChannel and LACP configuration for WLC trunking
Rate this question

Topics

WLAN Infrastructure Connections and LAG

More questions from this topic