"Indicates the mode of the prefix set, in terms of which\naddress families (IPv4, IPv6, or both) are present. The\nmode provides a hint, but the device must validate that all\nprefixes are of the indicated type, and is expected to\nreject the configuration if there is a discrepancy. The\nMIXED mode may not be supported on devices that require\nprefix sets to be of only one address family." . . . . . . .