The ACSE supports two modes of communication: connection-oriented and connectionless.
The ACSE service definition (ITU-T Rec. X.217 I ISO/IEC 8649) includes both modes of communication. This Protocol Specification provides the protocol specification for the connection-oriented mode of communication. The protocol specification for the connectionless mode of communication is contained in ITU-T Rec. X.237 I ISO/IEC 10035 1. This Protocol Specification defines procedures that are applicable to instances of communication between systems which wish to interconnect in an Open Systems Interconnection environment in a connection-oriented mode. The Protocol Specification includes the Kernel functional unit that is used to establish and release application-associations. The Authentication functional unit provides additional facilities for exchanging information in support of authentication during association establishment without adding new services. The ACSE authentication facilities can be used to support a limited class of authentication methods. The Application Context Negotiation functional unit provides additional facility for the selection of the application context during association establishment.
This Protocol Specification specifies:
a) procedures for the transfer of information application-entities; for application-association control and the authentication of
b) the interaction between an ACSE protocol machine and the occurrence of external presentation events; and
c) the abstract syntax for the representation of the ACSE APDUs. The ACSE procedures are defined in terms of:
a) the interactions between peer ACSE protocol machines through the use of presentation-services; and
b) the interaction between an ACSE protocol machine and its service-user. This Protocol Specification also specifies conformance requirements for systems implementing these procedures. It does not contain tests which can be used to demonstrate conformance.