An engineer must establish a trunk link between two switches. The neighboring switch is set to trunk or desirable mode. What action should be taken?

`switchport nonegotiate` disables DTP and requires the port to be explicitly configured as `switchport mode trunk` to form a trunk, which bypasses dynamic negotiation.

`switchport mode dynamic desirable` actively attempts to form a trunk link, which would work, but `dynamic auto` is a more passive and often sufficient configuration when the neighbor is already actively seeking a trunk or fixed in trunk mode.

When a neighboring switch port is configured as `trunk` or `dynamic desirable`, setting the local switch's port to `dynamic auto` will cause it to passively form a trunk link. The `dynamic auto` mode waits for the neighbor to actively negotiate or be set as a trunk.

`switchport trunk dynamic desirable` is not a valid Cisco IOS command syntax for configuring DTP modes.