The ipv6 mtu spread command sets an MTU value for IPv6 packets to be sent by an interface and applies the MTU value to sub-interfaces created on the interface.
The undo ipv6 mtu spread command restores the default MTU value for IPv6 packets to be sent by an interface and deletes the MTU value applied to the sub-interfaces created on the interface.
By default, the MTU value is 1500 bytes.
Usage Scenario
Sub-interfaces can inherit the MTU value of the interface where the sub-interfaces reside. In this situation, you can run the ipv6 mtu spread command to change the MTU value of the interface. The MTU values of sub-interfaces are then changed in batches.
If a sub-interface has its own MTU configuration, the MTU value configured using the ipv6 mtu spread command does not take effect for the sub-interface MTU. This command takes effect only after the MTU configuration is deleted from the sub-interface.Precautions