< AA - Request > : := < Diameter Header : 265 , REQ , PXY > < Session - Id > { Auth - Application - Id } { Origin - Host } { Origin - Realm } { Destination - Realm } *[ Media - Component - Description ] *[ Flow - Grouping ] [ AF - Charging - Identifier ] [ Service - Identifier ] [ SIP - Forking - Indication ] *[ Specific - Action ] *[ Subscription - ID ] *[ Proxy - Info ] *[ Route - Record ] *[ AVP ]