System Mtu - Cisco Catalyst 3750 Command Reference Manual

system mtu

system mtu
Use the system mtu global configuration command on the switch stack or on a standalone switch to set
the maximum packet size or maximum transmission unit (MTU) size for Gigabit Ethernet ports or for
Fast Ethernet (10/100) ports. Use the no form of this command to restore the global MTU value to its
default value.
Syntax Description bytes
jumbo bytes
Defaults
The default MTU size for all ports is 1500 bytes.
Command Modes Global configuration
Command History Release
12.1(11)AX
Usage Guidelines When you use this command to change the MTU size, you must reset the switch before the new
configuration takes effect.
Gigabit Ethernet ports are not affected by the system mtu command; Fast Ethernet ports are not affected
by the system mtu jumbo command.
If you enter a value that is outside the range for the specific type of switch, the value is not accepted.
Note The switch does not support setting the MTU on a per-interface basis.
The size of frames that can be received by the switch CPU is limited to 1500 bytes, no matter what value
was entered with the system mtu command. Although frames that are forwarded or routed typically are
not received by the CPU, in some cases packets are sent to the CPU, such as traffic sent to control traffic,
SNMP, Telnet, or routing protocols.
Examples This example shows how to set the maximum packet size for Gigabit Ethernet ports to 1800 bytes:
Switch(config)# system mtu jumbo 1800
Switch(config)# exit
Switch# reload
Catalyst 3750 Switch Command Reference
2-594
system mtu {bytes | jumbo bytes}
no system mtu
Set the system MTU for Fast Ethernet (10/100) ports. The range is 1500 to
1546 bytes.
Set the system jumbo frame size (MTU) for Gigabit Ethernet ports. The
range is 1500 to 9000 bytes.
Modification
This command was introduced.
Chapter 2 Catalyst 3750 Switch Cisco IOS Commands
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