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ISO ACSE: Association Control Service Element
The ISO Association Control Service Element (ACSE), an application layer protocol in the OSI model, is to establish and release an application-association between two AEIs and to determine the application context of that association. The ACSE supports two modes of communication: connection-oriented and connectionless. For the connection-oriented mode, the application-association is established and released by the reference of ACSE connection oriented services. For the connectionless mode, the application-association exists during the invocation of the single ACSE connectionless mode service, A-UNIT-DATA .
The applications in the OSI reference model represent communication between a pair of application-processes (APs) in terms of communication between their application-entities (AEs) using the presentation-service. The functionality of an AE is factored into a number of application-service-elements (ASEs). The interaction between AEs is described in terms of the use of their ASEs? services. This Service Definition supports the modeling concepts of application-association and application context.
An application-association is a cooperative relationship between two AEIs. It provides the necessary frame of reference between the AEIs in order that they may interwork effectively. This relationship is formed by the communication of application protocol control information between the AEIs through their use of the presentation-service.
An application context is an explicitly identified set of application-service-elements, related options and any other necessary information for the interworking of application-entities on an application association.
The ACSE service-user is that part of an application-entity that makes use of ACSE services. It may be the Control Function (CF) or an ASE or some combination of the two.
The services provided by ACSE are listed as follows:
|
Communication mode |
Service |
Type |
|
Connection oriented |
A-ASSOCIATE
A-RELEASE
A-ABORT
A-P-ABORT |
Confirmed
Confirmed
Non-confirmed
Provider-initiated |
|
Connectionless |
A-UNIT-DATA |
Non-confirmed |
Protocol Structure - ISO ACSE: Association Control Service Element The functions, services and message structure are listed as follows:
|
Functional Unit |
Service |
APDU |
Field Name |
|
Kernel |
A-ASSOCIATE |
AARQ |
Protocol Version
Application Context Name
Calling AP Title
Calling AE Qualifier
Calling AP Invocation-identifier
Calling AE Invocation-identifier
Called AP Title
Called AE Qualifier
Called AP Invocation-identifier
Called AE Invocation-identifier
Implementation Information
User Information |
|
|
|
AARE |
Protocol Version
Application Context Name
Responding AP Title
Responding AE Qualifier
Responding AP Invocation-identifier
Responding AE Invocation-identifier
Result
Result Source-Diagnostic
Implementation Information
User Information |
|
|
A-RELEASE |
RLRQ |
Reason
User Information |
|
|
|
RLRE |
Reason
User Information |
|
|
A-ABORT |
ABRT |
Abort Source
User Information |
|
Authentication |
A-ASSOCIATE |
AARQ |
ACSE Requirements
Authentication-mechanism Name
Authentication-value |
|
|
|
AARE |
Ditto |
|
|
|
ABRT |
Diagnostic |
|
Application Context
Negotiation |
A-ASSOCIATE |
AARQ |
Application Context Name List
ACSE Requirements |
|
|
|
AARE |
Ditto |
Related Protocols
Session Protocol, Presentation Protocol , ROSE
Sponsor Source
The ACSE protocol is defined in ISO (www.iso.org ) documents 8650 and 8649 and ITU (www.itu.org ) documents X.217, X.227, X.237.
Reference
http://www.doc.ua.pt/arch/itu/rec/product/X.htm :
X.217: Information technology - Open Systems Interconnection - Service definition for the Association Control Service Element
X.227: Information technology - Open Systems Interconnection - Connection-oriented protocol for the Association Control Service Element: Protocol specification
X.237: Information technology - Open Systems Interconnection - Connectionless protocol for the Association Control Service Element: Protocol specification |
