1、INTERNATIONAL STANDARD ISOIIEC 9066-I First edition 1989-11-15 Information processing systems - Text communication - Reliable Transfer - Part 1 : Model and service definition Syst application-process; application-entity; application-service-element; application-protocol-data-unit; application-protoc
2、ol-control-information; Presentation Layer; presentation-service; presentation-connection; session-service; session-connection; transfer syntax; two-way-alternate interaction; and user-element. 1 ISOAEC 9066-I : 1989 (E) 3.2 Service conventions definitions This part of ISO/IEC 9066 makes use of the
3、following terms defined in ISO/TR 8509: a) service-provider; b) service-user; C) confirmed service; dl non-confirmed service; e) provider-initiated service; f-3 service-primitive; primitive; g) request (primitive); h) indication (primitive); il response (primitive); and j) confirm (primitive). 3.3 P
4、resentation service definitions This part of ISO/IEC 9066 makes use of the following terms defined in IS0 8822: a) abstract syntax; b) abstract syntax name; cl default context; d) presentation context; e) transfer syntax name. 3.4 Association control definitions This part of ISO/IEC 9066 makes use o
5、f the following terms defined in IS0 8649: a) application-association; association; b) application context; C) Association Control Service Element; d) X.410-1984 mode. 3.5 Reliable Transfer definitions For the purpose of this part of ISO/IEC 9066 the following definitions apply: 3.5.1 association-in
6、itiating-application- entity; association-initiator: The application- entity that initiates the application-association. 3.5.2 association-responding-application- entity; association-responder: The application- entity that responds to the initiation of an application-association by another AE. 3.5.3
7、 sending-application-entity; sender: The application-entity that sends, or may send, (i.e. possesses the Turn) the APDU to the receiving application-entity. 3.5.4 receiving-application-entity; receiver: The application-entity that receives, or may receive, (i.e. does not possess the Turn) the APDU f
8、rom the sending application-entity. 3.5.5 requestor: The part of an application- entity that issues a request primitive, or receives a confirm primitive for a particular RTSE service. 3.5.6 acceptor: The part of an application- entity that receives the indication primitive, or issues a response prim
9、itive for a particular RTSE service. 3.5.7 Reliable Transfer Service Element: The application-service-element defined in this part of ISO/IEC 9066. 3.5.8 Reliable Transfer: An application- independent mechanism to provide for the transfer of application-protocol-data-units between open systems, and
10、to recover from communication and end-system failure minimizing the amount of retransmission. 3.5.9 RTSE-user: The user of the Reliable Transfer Service Element. The user may be the user element, or another application service element, of the application entity. 3.5.10 RTSE-provider: The provider of
11、 the Reliable Transfer Service Element. 3.5.11 ACSE-provider: The provider of the Association Control Service Element. 3.5.12 monologue interaction: A mode of interaction where only one application-entity may be the sender. ISOAEC 9066-I : 1989 (E) 3.5.13 syntax-matching-services: Local services pro
12、vided by the presentation-service provider enabling the transformation from the local representation of an application-protocol- data-unit value into a representation specified by a negotiated transfer syntax and vice versa. 3.5.14 X.410-1984 mode: A restricted mode of operation of the Reliable Tran
13、sfer Service Element to allow interworking with application- entities based on CCITT Recommendation X.410 - 1984. 3.5.15 normal mode: A mode of operation of the Reliable Transfer Service Element providing full services. 4 Abbreviations AE ACSE APDU ASE OS1 RT (or RTS) application-entity Association
14、Control Service Element application-protocol-data-unit application-service-element Open Systems Interconnection Reliable Transfer RTSE Reliable Transfer Service Element 5 Conventions This part of ISO/IEC 9066 defines services for the RTSE following the descriptive conventions defined in ISO/TR 8509.
15、 In clause 9, the definition of each RTSE service includes a table that lists the parameters of its primitives. For a given primitive, the presence of each parameter is described by one of the following values. blank not applicable M mandatory U user option C conditional T presence is an RTSE-provid
16、er option A presence subject to conditions defined in IS0 8649. P presence subject to conditions defined in IS0 8822. In addition, the notation (=) indicates that a parameter value is semantically equal to the value to its left in the table. 3 ISOAEC 9066-l : 1989 (E) 6 Reliable Transfer Model In th
17、e OS1 environment, communication between application-processes is represented in terms of communication between a pair of application- entities (AEs) using the presentation-service. Communication between some application- entities requires the Reliable Transfer of application-protocol-data-units (AP
18、DUs). APDUs sent by one AE (the sender) are received by the other AE (the receiver). Reliable Transfer ensures that each APDU is completely transferred between AEs exactly once, or that the sending AE is warned of an exception. Reliable Transfer recovers from communication and end-system failure and
19、 minimizes the amount of retransmission needed for recovery. The APDUs transferred are transparent to the Reliable Transfer. Reliable Transfer is carried out within the context of an application-association. An application-association defines the relationship between a pair of AEs, and is formed by
20、the exchange of application-protocol-control- information through the use of presentation- services. The AE that initiates an application- association is called the association-initiating AE, or the association-initiator, while the AE that responds to the initiation of an application-association by
21、another AE is called the association-responding AE, or the association- responder. Only the association-initiator may release an established application-association. The functionality of an AE is factored into one user-element and a set of application-service- elements (ASEs). Each ASE may itself be
22、 factored into a set of (more primitive) ASEs. The interaction between AEs is described in terms of their use of ASEs. The specific combination of a user-element and the set of ASEs which comprise an AE are defined by the application context. Figure 1 illustrates an example of an application context
23、 involving the Reliable Transfer Service Element (RTSE). The ASEs available to the user-element require communication over an application-association. The control of that application-association (establishment, release, abort) and the Reliable Transfer of APDUs over the application- association is p
24、erformed by the Reliable Transfer Service Element (RTSE) defined in this part of lSO/lEC 9066. The RTSE uses the Association Control Service Element (ACSE) defined in IS0 8649 for control of that application-association (establishment, release, abort). Note that the application context depicted in f
25、igure 1 is minimal for an application context involving RTSE. Another example, taken from message handling (lSO/lEC 10021-61, of an application context involving RTSE, could be that of a message transfer agent (MTA), and would include the message transfer service element (MTSE) in addition to the AC
26、SE and the RTSE. Note also that, in general, it is the responsibility of a International Standard defining a set of ASEs that make use of the RTSE (and the ACSE), to define what use is made of the RTSE and any restrictions that may apply. ISOAEC 9066-l : 1989 (E) I I I I I I I I I I I I I I l I I I
27、I I I I I I t I I I I I I I I I I I I I g .4 I 4 I I 8 I 2 i 8 I I c: I 0 I 3 I a I I 2 , s I I E I $2 I I I I I I I I I I I I I I I I t: I I I I I I I I I I I I I I I I I 5 ISOAEC 9066-l : 1989 (E) 7 Overview of service partially received APDU prior to issuing the RT- P-ABORT indication. This part
28、1 of lSO/lEC 9066 defines the following services for Reliable Transfer: The RT-U-ABORT service enables an RTSE-user a1 RT-OPEN to abort the application-association. b) RT-CLOSE The Reliable Transfer is provided in two modes of cl RT-TRANSFER operation: d) RT-TURN-PLEASE a1 X.410-1984 mode: is provid
29、ed solely to allow interworking with older implementations based on CCITT Recommendation X.410-1984. This mode implies some restriction in the use of RTSE services; e) RT-TURN-GIVE fl RT-P-ABORT g) RT-U-ABORT The RT-OPEN service enables an RTSE-user to request the establishment of an application- as
30、sociation with another AE. The RT-CLOSE service enables the association- initiating RTSE-user to request the release of an established application-association. It may do so only if it possesses the Turn. The RT-TRANSFER service enables an RTSE- user that possesses the Turn, to request the Reliable T
31、ransfer of an APDU over an application-association. It may do so only on an established application-association and when there is no outstanding RT-TRANSFER confirm primitive. The RT-TURN-PLEASE service enables an RTSE-user to request the Turn. It may do so only if it does not already possess the Tu
32、rn. The Turn is requested by either RTSE-user to allow the RTSE- user to transfer APDUs. The Turn is requested by the association-initiating RTSE-user to allow it to release the application-association. The request conveys the priority of the action to be taken so that the other RTSE-user can decide
33、 when to actually relinquish the Turn. The RT-TURN-GIVE service enables an RTSE- user to relinquish the Turn to its peer. It may do SO only if it possesses the Turn. The RT-P-ABORT service provides an indication to the RTSE-user that the application-association cannot be maintained (e.g., because re
34、covery not possible, etc.). If it is the sender, the RTSE- provider first issues a negative RT-TRANSFER confirm for the APDU not yet transferred. If it is the receiver, the RTSE-provider deletes the b) normal mode: is provided to allow full use of RTSE services. 8 Relationship with other ASEs and lo
35、wer layer services 8.1 Other application-service-elements The RTSE is intended to be used with other ASEs in order to support specific information processing tasks that require the Reliable Transfer of application-protocol-data-units. Therefore, it is expected that the RTSE will be included in a num
36、ber of application context specifications. The collection of the RTSE and other ASEs (in particular ACSE) included in an application context are required to use the facilities of the presentation-service in a co-ordinated manner among themselves. The RTSE requires the control of an application- asso
37、ciation by the ACSE. For application contexts that involve RTSE, the RTSE-provider is the user of the A-P-ABORT service; the A-P-ABORT service is not used directly by the user-element nor by any other ASE. In the event of the RTSE- provider receiving an A-P-ABORT indication from the ACSE-provider, t
38、he RTSE-provider will attempt to recover the presentation-connection by issuing an A-ASSOCIATE request. If the presentation-connection cannot be recovered, the RTSE-provider will issue an RT-P-ABORT indication to the RTSE-user. The A-ABORT service provided by the ACSE is used by the RTSE-provider. An RTSE-user protocol specification defines the types of user-data parameter values of the RTSE services forming one or more abstract syntaxes
