Answer is 'C'... channel-mode on
Configuring Neighbor Devices to Support LAG
The controller's neighbor devices must also be properly configured to support LAG.
â¢Each neighbor port to which the controller is connected should be configured as follows:
interface GigabitEthernet
switchport
channel-group mode on
no shutdown
â¢The port channel on the neighbor switch should be configured as follows:
interface port-channel
switchport
switchport trunk encapsulation dot1q
switchport trunk native vlan
switchport trunk allowed vlan
switchport mode trunk
no shutdown
Here is a link that explains it. Hope this answers your question:
http://www.cisco.com/en/US/docs/wireless/controller/4.2/configuration/guide/c42mint.html#wp1116136
Here is a Best Practice doc:
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a0080810880.shtml
-Scott
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