Configuring an MPLS MTU on an Interface

An MPLS MTU can be configured on an interface to determine the maximum number of bytes in an MPLS packet that an interface can forward without fragmenting the packet.

Context

The MPLS MTU is a forwarding plane parameter and is irrelevant to LSP establishment. The dependency between the MPLS MTU and the interface MTU is as follows:

If no MPLS MTU is set and an interface MTU is set on an interface, the interface MTU is used.
If an MPLS MTU and an interface MTU are set on an interface, the smaller value between the MPLS MTU and interface MTU is used.

Procedure

Run system-view
The system view is displayed.
Run interface interface-type interface-number
The view of an MPLS-enabled interface is displayed.
Run mpls mtu mtu
An MPLS MTU is set on the interface.

The configured MPLS MTU takes effect immediately, and there is no need to restart the interface.

If the MPLS MTU configured using the mpls mtu command is used as the MPLS forwarding MTU, run the mpls path-mtu independent command to allow the MPLS MTU to take effect without being affected the interface MTU. The mpls path-mtu independent command is used when a Huawei device communicates with a non-Huawei device, which prevents low MPLS forwarding efficiency stemming from different MTU implementations.
Run commit
The configuration is committed.