How do you configure a Layer 3 EtherChannel?

To configure a Layer 3 EtherChannel, the correct approach is to ensure that the interfaces participating in the EtherChannel are set to Layer 3 mode. This is accomplished by using the command that disables the switchport functionality on those interfaces, allowing them to operate as routed interfaces rather than switch ports.

Using the command "no switchport" transforms the interface from Layer 2 (switching mode) to Layer 3 (routing mode). In Layer 3 mode, these interfaces can participate in routing protocols, allowing the EtherChannel to aggregate bandwidth and provide redundancy between routers or multilayer switches.

In contrast, the other options do not address configuring an interface for EtherChannel in Layer 3. Exiting layer 3, setting a Layer 3 channel, or configuring a switchport mode trunk don't pertain to the correct setup needed for a Layer 3 EtherChannel. Specifically, a trunking configuration applies to Layer 2 EtherChannels, which is not the goal when establishing a Layer 3 EtherChannel. Therefore, specifying "no switchport" is essential for correctly configuring this type of EtherChannel.