Some properties, including the MTU property, are common to both datalinks and IP interfaces. Thus, you can have one MTU value for a datalink and a different MTU value for the interface that is configured over that link. Further, you can have different MTU values that apply to the IPv4 and IPv6 packets that traverse that IP interface.
When setting MTU properties for an IP interface, keep the following key points in mind:
The value of the MTU setting of an IP interface cannot be larger than the value of the MTU setting of a datalink. In such cases, the ipadm command displays an error message.
If an IP interface's MTU value is different than a datalink's MTU value, IP packets are limited to the MTU value of the IP interface. For example, if a datalink has an MTU value of 9000 bytes and an IP interface as an MTU value of 1500 bytes, IP packets are limited to 1500 bytes. However, other Layer 3 protocols that are using the underlying Layer 2 protocol can send packets up to 9000 bytes.
For instructions on customizing datalink properties, including information about how the MTU setting of a datalink impacts the MTU setting of an IP interface, see Customizing Datalink Properties.