What is the main function of the DTP protocol on Cisco switches?

The main function of the DTP (Dynamic Trunking Protocol) on Cisco switches is to manage the negotiation of trunk links between switches. DTP allows switches to automatically negotiate whether an interface should operate as an access port or a trunk port. By doing this, it helps in determining the status of the interface by establishing if it should be sending VLAN traffic.

When DTP is enabled, it can automatically detect other DTP-enabled switches and negotiate trunking parameters such as encapsulation type (either ISL or 802.1Q). This process ensures that the appropriate configuration is applied to the interface based on the capabilities of the connected device, thereby simplifying the management of VLANs and trunk links.

The other options do not directly relate to the functionality provided by DTP. While configuring VLANs and enabling routing are essential tasks for network management, they are not the primary role of DTP. DTP does not manage IP addresses, nor is its main purpose to enable routing within a network. Thus, understanding DTP's role in interface management and its negotiation of trunk links is crucial for optimizing switch configuration and improving network efficiency.