■ Have N non-overlapping ID ranges defined by (startID, sizeID) for each range ■ num = hash(unique_identifier_of_ID_server) % N ■ offset = f(unique_attribute_value) % sizeID[num] ■ POSIX-ID = startID[num] + offset ○ Hash is a configurable message digest function with configurable seed ○ f is configurable function取决于来自对象属性的唯一属性/索赔