What happens under DTP desirable mode?

When a switch port is configured to DTP (Dynamic Trunking Protocol) in desirable mode, it actively tries to negotiate trunking with the neighboring device. This mode sends DTP packets to the other device to request that a trunk link be established. If the adjacent device is also set to negotiate trunking (either in desirable mode or trunk mode), they will agree to form a trunk link.

This interaction is fundamental in environments with dynamic VLANs where trunking is essential for allowing multiple VLANs to be carried across a single physical link. By negotiating trunking, desirable mode facilitates flexibility and adaptability within a network configuration, allowing for dynamic responses to changes in the network topology.

The other options do not reflect the function of DTP in desirable mode. Access mode enforces that a port belong to a specific VLAN only, disabling any trunking negotiation. Disabling DTP entirely would mean that trunking negotiation cannot occur, which is not the case in desirable mode. Setting static VLANs doesn’t encompass the negotiation process that DTP facilitates; it instead locks a port into a specific VLAN configuration without the dynamic capabilities that DTP offers.