ip mtu

Use ip mtu to configure an MTU for an interface.

Use undo ip mtu to restore the default.

Syntax

ip mtu mtu-size

undo ip mtu

Default

No MTU is configured for an interface.

Views

Interface view

Predefined user roles

network-admin

Parameters

mtu-size: Specifies an MTU in the range of 128 to 2000 bytes.

Usage guidelines

When a packet exceeds the MTU of the output interface, the device processes it in one of the following ways:

• If the packet disallows fragmentation, the device discards it.

• If the packet allows fragmentation, the device fragments it and forwards the fragments.

Fragmentation and reassembling consume system resources, so set an appropriate MTU for an interface to avoid fragmentation.

If an interface supports both the mtu and ip mtu commands, the device fragments a packet based on the MTU set by the ip mtu command.

The MTU configured for an interface takes effect on only packets that are sent to the CPU for software forwarding, including packets sent from or destined for this interface.

Examples

# Set the MTU of VLAN interface 100 to 1280 bytes.

<Sysname> system-view
[Sysname] interface vlan-interface 100
[Sysname-Vlan-interface100] ip mtu 1280