Cisco WS-C3560-48PS-S Software Configuration Manual page 237

Chapter 10 Configuring Interface Characteristics
Beginning in privileged EXEC mode, follow these steps to change MTU size for all 10/100 or Gigabit
Ethernet interfaces:
Command
Step 1 configure terminal
Step 2
system mtu bytes
Step 3
system mtu jumbo bytes
Step 4
end
Step 5
copy running-config startup-config
Step 6
reload
If you enter a value that is outside the allowed range for the specific type of interface, the value is not
accepted.
Once the switch reloads, you can verify your settings by entering the show system mtu privileged EXEC
command.
This example shows how to set the maximum packet size for a Gigabit Ethernet port to 1800 bytes:
Switch(config)# system jumbo mtu 1800
Switch(config)# exit
Switch# reload
This example shows the response when you try to set Gigabit Ethernet interfaces to an out-of-range
number:
Switch(config)# system mtu jumbo 2500
% Invalid input detected at '^' marker.
78-16156-01
Purpose
Enter global configuration mode.
(Optional) Change the MTU size for all interfaces on
the switch that are operating at 10 or 100 Mbps. The
range is from 1500 to 1546 bytes; the default is 1500
bytes.
(Optional) Change the MTU size for all Gigabit
Ethernet interfaces on the switch. The range is from
1500 to 9000 bytes; the default is 1500 bytes.
Return to privileged EXEC mode.
Save your entries in the configuration file.
Reload the operating system.
^
Catalyst 3560 Switch Software Configuration Guide
Configuring the System MTU
10-21