Dynamic Trunking Protocol (DTP) Switch Port Modes

C

The answer to the question is C. dynamic desirable.

DTP stands for Dynamic Trunking Protocol, which is a Cisco proprietary protocol used to negotiate the creation of trunk links between switches. DTP is enabled by default on most Cisco switches, but it can be disabled on a per-port basis.

There are four DTP port modes:

1. Trunk mode: The port creates a trunk link regardless of the state of the neighboring port.

2. Access mode: The port does not create a trunk link and treats all incoming frames as belonging to the configured VLAN.

3. Dynamic desirable mode: The port creates a trunk link if the neighboring port is in trunk mode, dynamic desirable mode, or desirable auto mode.

4. Dynamic auto mode: The port creates a trunk link if the neighboring port is in trunk mode or dynamic desirable mode.

So, in the given scenario, the port mode that allows the port to create a trunk link if the neighboring port is in trunk mode, dynamic desirable mode, or desirable auto mode is dynamic desirable mode. In this mode, the port sends DTP frames indicating that it can create a trunk link, but it can also fall back to an access link if necessary.

It's worth noting that DTP is a legacy protocol and is not recommended for modern network design. In most cases, it's best to manually configure trunk links instead of relying on DTP to negotiate them automatically. Additionally, if you're configuring a switch port that connects to a non- Cisco device, it's important to disable DTP to prevent any unexpected trunk negotiations.