OSPF FAPM and interarea

The FAPM (Flexible Algorithm Prefix Metric) is defined to allow optimal end-to-end path for an inter-area prefix. The ABR (Area Border Router) MUST include the FAPM when advertising the prefix between areas that is reachable in that given Flex-Algorithm and when a prefix is unreachable the ABR MUST NOT include that prefix in that Flex-Algorithm when advertising between areas. The defined FAPM provides inter area support.