12. The apparatus of claim 9 , wherein the search request message comprises an Application Usage ID (AUID).
12. The apparatus of claim 9 , wherein the search request message comprises an Application Usage ID (AUID). 16. The apparatus of claim 12 , wherein the server is further configured to: reflect a preference weight value to the at least one external search domain, and set a preference level for the at least one external search domain according to a reflection result.