When troubleshooting a trunk port connected to a corporate network, what aspect should be checked first?

When troubleshooting a trunk port in a corporate network, checking the link state is crucial because it confirms whether the trunk port is operational and properly established between the connected devices. The link state indicates whether the connection is up and functioning; if the link is down, none of the other elements, such as traffic load or compatibility, will matter, as no data can be transmitted at all.

Verifying the link state can uncover issues such as mismatched configurations (like speed or duplex settings) and physical connection problems, which could be the root cause of a malfunctioning port. If the link state is intact and operational, the troubleshooting process can then proceed to assess other aspects like device compatibility, traffic load, or cabling integrity, but ensuring the link is up serves as the foundation for further diagnosis.