The Layer 2 Maximum Transmission Unit (L2MTU) refers to the maximum frame size that can be transmitted over a network interface.
Examples:
Viewing the Current MTU Settings:
# show system mtu
Changing the MTU Size (This command sets the MTU size to 1500 bytes. Note that changes to the MTU size typically require a reboot of the switch to take effect.):
# system mtu <size>
# system mtu 1500