This Recommendation | International Standard defines ACSE services for ASO-association control in an open systems
interconnection environment. ACSE supports two modes of communication service: connection-mode and
connectionless-mode.
The ACSE connection-mode service is provided by the use of the connection-mode ACSE protocol (see ITU-T
Rec. X.227 bis | ISO/IEC 15954).
The ACSE connectionless-mode service (A-UNIT-DATA) is provided by the use of the connectionless-mode ACSE
protocol (see ITU-T Rec. X.237 bis | ISO/IEC 15955).
Five functional units are defined in the ACSE. The mandatory Kernel functional unit is used to establish and release
ASO-associations. The optional Authentication functional unit provides additional facilities for exchanging information
in support of authentication during association establishment without adding services. The ACSE authentication
facilities may be used to support a limited class of authentication methods. The optional ASO-context negotiation
functional unit allows multiple ASO-contexts to be offered during association establishment. The optional higher level
association functional unit provides for the facility to identify ASO-associations and transparently pass data to child
ASOs and allows the ASO-context or the presentation context on an ASO-association to be modified during the lifetime
of the association.
This Recommendation | International Standard does not specify individual implementations or products, nor does it
constrain the implementation of entities and interfaces within a computer system.
No requirement is made for conformance to this Service definition.