Rec. X.236 [ISO/IEC 9576-1] This layer defines and encrypts/decrypts data types from the application layer. Protocols such as MIDI, MPEG, and GIF are presentation layer formats shared by different applications. Layer 7: application layer Common-Application Service Elements (CASEs) Association Control Service Element (ACSE) – ITU-T Rec. X.217 [ISO/IEC 8649], ITU-T Rec. X.227 [ISO/IEC 8650-1], ITU-T Rec. X.237 [ISO/IEC 10035-1]. Reliable Transfer Service Element (RTSE) – ITU-T Rec. X.218 [ISO/IEC 9066-1], ITU-T Rec. X.228 [ISO/IEC 9066-2]. Remote Operations Service Element (ROSE) – ITU-T Rec. X.219 [ISO/IEC 9072-1], ITU-T Rec. X.229 [ISO/IEC 9072-2]. TCAP is related to X.219. Commitment, Concurrency, and Recovery service element (CCRSE) Security Exchange Service Element (SESE) This keeps track of how each application talks to another application. Destination and source addresses are linked to specific applications. Application processes Common management information protocol (CMIP) – ISO 9596 / X.700 Directory services (DS) – X.500, later modified for the TCP/IP stack as LDAP File transfer, access, and management (FTAM) Message handling system (MHS) – X.400 Virtual terminal protocol (VT) - ISO 9040/9041 Remote Database Access (RDA) Distributed Transaction Processing (OSI TP) Interlibrary Loan Application Protocol (ILAP) Document Transfer And Manipulation (DTAM) Document Printing Application (DPA) Document Filing and Retrieval (DFR) Routing protocols Intermediate System to Intermediate System (IS-IS) – ISO 10589 (reprinted in RFC 1142) End System to Intermediate System (ES-IS) – ISO 9542 (reprinted in RFC 995) Interdomain Routing Protocol (IDRP) – ISO 10747 See also Protocol stack Protocol Wars WAP protocol suite References Network architecture Reference models