ipv6 mtu

Function

The ipv6 mtu command sets the maximum transfer unit (MTU) value for an interface to send IPv6 packets.

The undo ipv6 mtu command restores the default MTU value for an interface to send IPv6 packets.

By default, the default value of the MTU is 1500 bytes.

Format

ipv6 mtu mtu

undo ipv6 mtu

Parameters

Parameter	Description	Value
mtu	Specifies the MTU for an interface to send IPv6 packets.	Ethernet interface and its sub-interface: The MTU value is an integer ranging from 1280 to 1500, in bytes. The default value is 1500. GE interface and its sub-interface: The MTU value is an integer ranging from 1280 to 9600, in bytes. The default value is 1500. Tunnel interface: The MTU value is an integer ranging from 1280 to 9600, in bytes. The default value is 1500.

Parameter

Description

Value

mtu

Specifies the MTU for an interface to send IPv6 packets.

Ethernet interface and its sub-interface: The MTU value is an integer ranging from 1280 to 1500, in bytes. The default value is 1500.
GE interface and its sub-interface: The MTU value is an integer ranging from 1280 to 9600, in bytes. The default value is 1500.
Tunnel interface: The MTU value is an integer ranging from 1280 to 9600, in bytes. The default value is 1500.

Views

100ge sub-interface view, 100GE interface view, 10GE sub-interface view, 10GE interface view, 200GE sub-interface view, 25GE sub-interface view, 25GE interface view, 400GE sub-interface view, 400GE interface view, 40GE sub-interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk sub-interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE sub-interface view, GE interface view, GE electrical interface view, Global VE sub-interface view, PW-VE sub-interface view, PW-VE interface view, Tunnel interface view, VBDIF interface view, VE sub-interface view, VLANIF interface view, Management interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
interface-mgr	write

Usage Guidelines

Usage Scenario

If the traffic capability on a link between the source and destination ends changes, this ipv6 mtu command is used to set the MTU value for sending IPv6 packets. If the packet length is greater than the IPv6 MTU of the interface, the system fragments the packet based on the set MTU value before forwarding the packet.

Configuration Impact

A dynamic path maximum transfer unit (PMTU) value is set based on IPv6 MTU values on interfaces.

The PMTU mechanism helps the system obtain the smallest value among MTU values on all interfaces on the path between the source and destination ends.

If the IPv6 MTU value set using the ipv6 mtu command is smaller than the static PMTU value set using the ipv6 pathmtu command, the system fragments the packet based on the set MTU value before forwarding the packet.

Precautions

The directly connected interfaces must assigned the same IPv6 MTU value.

Example

# Set the IPv6 MTU value to 1400 for an Eth-Trunk interface.

<HUAWEI> system-view
[~HUAWEI] interface eth-trunk 1
[*HUAWEI-Eth-Trunk1] ipv6 enable
[*HUAWEI-Eth-Trunk1] ipv6 mtu 1400

# Set the IPv6 MTU value to 1400 for GE 0/1/1.

<HUAWEI> system-view
[~HUAWEI] interface GigabitEthernet0/1/1
[*HUAWEI-GigabitEthernet0/1/1] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/1] ipv6 mtu 1400