What must be done to change the MTU size on a switch?

To change the Maximum Transmission Unit (MTU) size on a switch, the correct approach is to use the interface command. This command allows you to specify the MTU size on a specific interface of the switch. After configuring the desired MTU size, the change typically takes effect immediately.

Rebooting the switch is not necessary for the configuration changes related to MTU settings, as switches usually apply the new MTU size without requiring a restart. Similarly, adjusting system variables or increasing VLAN limits does not directly relate to changing the MTU size on an interface. Therefore, the interface command is essential for properly modifying the MTU on a switch.