Final answer:
A network technician suspects a duplex mismatch between two Cisco switches, the technician should use the 'show interfaces' Cisco IOS command followed by the interface identifier to diagnose the issue. It provides Layer 1 and Layer 2 details that can reveal a disparity in duplex settings, which should match on both ends for proper network function.
Step-by-step explanation:
To investigate a suspected duplex mismatch on a network connection between two Cisco switches, a network technician would use the Cisco IOS command show interfaces. This command provides detailed information about the interface's status, including the Layer 1 and Layer 2 details such as protocol status, speed, and duplex settings.
To use the command effectively, the technician should access the switch console and enter the command followed by the specific interface identifier, like so: show interfaces GigabitEthernet0/1 (replace GigabitEthernet0/1 with the actual interface identifier). This will display the operational status of the interface, the speed at which it is set to operate, and whether the duplex mode is set to half or full. Having a duplex mismatch means that one side operates in full duplex while the other is in half duplex, which can lead to excessive collisions and poor network performance.
The command should be run on both switches connected by the problematic link to compare the settings and resolve any mismatches. Typically, both ends should be set to either auto-negotiate or to the same fixed speed and duplex settings to ensure proper communication.