System Mtu - Cisco 4500M Command Reference Manual

Chapter2 Cisco IOS Commands for the Catalyst 4500 Series Switches

system mtu

To set the maximum Layer 2 or Layer 3 payload size, use the system mtu command. To revert to the
default MTU setting, use the no form of this command.
Syntax Description
datagram-size
Defaults
The default MTU setting is 1500 bytes.
Command Modes
Global configuration
Command History Release
12.1(12c)EW
Usage Guidelines
The datagram-size parameter specifies the Ethernet payload size, not the total Ethernet frame size, and
the Layer 3 MTU is changed as a result of changing the system mtu command.
For ports from 3 to18 on linecard model WS-X4418-GB and ports from 1 to 12 on model
WS-X4412-2GB-TX, only the standard IEEE Ethernet payload size of 1500 bytes is supported.
For other modules, an Ethernet payload size of up to 1552 bytes is supported, with a total Ethernet frame
size of up to 1600 bytes.
Examples
This example shows how to set the MTU size to 1550 bytes:
Switch# conf igure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# system mtu 1550
Switch(config)# end
Switch#
This example shows how to revert to the default MTU setting:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# no system mtu
Switch(config)# end
Switch#
Related Commands
show interfaces
show system mtu
78-16201-01
system mtu datagram-size
no system mtu
Specifies the Layer 2 payload size; valid values from 1500 to 1552 bytes.
Modification
Support for this command was introduced on the Catalyst 4500 series switch.
Catalyst4500 Series SwitchCiscoIOS Command Reference—Release 12.2(18)EW
system mtu
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