When the device has paths from multiple routing protocols to the same destination, it compares the administrative distances of the paths and selects the path with the lowest administrative distance to place in the IPv6 route table.
For example, if the device has a path from iBGP, from OSPFv3, and IPv6 IS-IS to the same destination, and all the paths are using their protocols‘ default administrative distances, the device selects the OSPFv3 path, because that path has a lower administrative distance than the iBGP and IPv6 IS-IS paths.
The default IPv6 administrative distances on the device are:
Lower administrative distances are preferred over higher distances. For example, if the device receives routes for the same network from IPv6 IS-IS and from iBGP, it will prefer the IPv6 IS-IS route by default.