mtu

Description

Sets the MTU (maximum transmission unit) for an interface. This defines the maximum size of a layer 2 (Ethernet) frame. Frames larger than the MTU (1500 bytes by default) are dropped and cause an ICMP fragmentation-needed message to be sent back to the originator.

To support jumbo frames (frames larger than 1522 bytes), increase the MTU as required by your network. A frame size of up to 9198 bytes is supported.

The largest possible layer 1 frame will be 18 bytes larger than the MTU value to allow for link layer headers and trailers.

The no form of this command sets the MTU to the default value 1500.

Command context

config-if

Parameters

<VALUE>

Specifies the MTU in bytes. Range: 46 to 9198. Default: 1500.

Authority

Administrators

Examples

Setting the MTU on interface 1/1/1 to 1000 bytes:

switch(config)# interface 1/1/1
switch(config-if)# mtu 1000

Setting the MTU on interface 1/1/1 to the default value:

switch(config)# interface 1/1/1
switch(config-if)# no mtu