Switch#show running-config | section interfaceinterface gigabitEthernet0/1ip address 192.

GigabitEthernet interfaces are capable of 1000 Mbps, but the actual link speed is determined by negotiation between the switch port and the connected device, along with the quality/type of cabling. In this configuration, Sales and CustomerService ports are manually set to speed 1000 and duplex full, which forces gigabit operation. However, the Marketing port is set to speed auto and duplex auto. If the connected endpoint, patch cable, wall jack, or intermediate wiring for Marketing cannot support gigabit (or has a termination problem), the link may auto-negotiate down to 100 Mbps or 10 Mbps. That creates a clear performance bottleneck for that department compared to the other two ports running at 1 Gbps.

The IP addresses shown are consistent within the same /24 network and do not indicate an obvious addressing problem, so “incorrect IP addresses” is unlikely. “Subnet error” is not supported by the given config, and Cat 5e is generally capable of gigabit at typical distances, so “outdated” cable is not the best explanation from these choices. The most likely cause is Marketing running at 10/100 due to negotiation.