OSPFv3 can be configured to advertise its locally generated router LSAs with a maximum metric to direct transit traffic away from the device, while still routing for directly connected networks.
By advertising the maximum metric, the device does not attract transit traffic. A device which does not handle transit traffic, and only forwards packets destined for its directly connected links, is known as a stub router. In OSPFv3 networks, a device could be placed in a stub router role by advertising large metrics for its connected links, so that the cost of a path through the device becomes larger than that of an alternative path.
You can configure OSPFv3 max-metric router LSA in either startup or non-startup mode. Configuring max-metric on startup may be helpful on ASBRs where protocols such as BGP converge after OSPF converges. Configuring max-metric on non-startup may be helpful in database overflow scenarios.
Note
The on-startup configuration does not apply to NSR restarts.