GB/T 15695-1995 Information processing systems Open Systems Interconnection Connection-oriented presentation service definition
Some standard content:
National Standard of the People's Republic of China
Information processing systems-Open Systems Interconnection
Connection-oriented presentation service definition
Information pracessing systems-Open SystemsInterconuection-Connection oriented presentation service definitionGB/T 15695—1995
IS08822-1988
This standard is equivalent to the international standard IS08822—1988 "Information processing systems-Open Systems Interconnection-Connection-oriented presentation service definition".
0 Introduction
This standard is one of a group of standards developed to facilitate the interconnection of information systems. It is related to other standards in a group of standards defined by the Open Systems Interconnection Reference Model (GB9387-88). The reference model subdivides the field of interconnection standardization into a series of specification layers with manageable size.
The purpose of Open Systems Interconnection is to enable information processing systems of all kinds to interconnect with as few technical agreements as possible beyond the interconnection standards. These systems may be from different manufacturers; have different management styles; have different levels of complexity; and belong to different periods of time.
This standard defines the services that entities in the application layer of the reference model can use. This standard recognizes that application entities may wish to communicate with each other for a variety of reasons, but not all systems use the same method to represent the information they wish to communicate, and therefore should agree on the main issues to be communicated and the meaning to be given to that information. The presentation service provides an appropriate method of transmitting information, ensuring that the semantics remain unchanged during the transmission process. It is recognized that, with respect to the Quality of Service (QOS) described in clause 9, work is still in progress to provide an integrated treatment of QOS involving all layers of the reference model and to ensure that the individual treatments in each layer consistently meet the overall objectives of QOS. Therefore, a supplement may be added to this standard to reflect the further development and integration of QOS. 1 Subject matter and scope
1.1 This standard defines (in an abstract way) the externally visible services provided by the OSI presentation layer in terms of: a. primitive actions and events at the user/service boundary; b. Parameter data related to actions and events; the relationship between these actions and events and their effective sequence. C
1.2 The services defined in this standard are provided by the OSI presentation protocol (in conjunction with the SI session service) and are available to various OSI application protocols.
1.3 This standard is not a specification for implementations or products, nor does it constrain the implementation of entities and interfaces within a computer system, and does not involve the question of whether it is consistent with this standard.
Approved by the State Administration of Technical Supervision on August 30, 1995 and implemented on April 1, 1996
2 Referenced standards
GB/T 156951995
GB 9387-88 Information processing system Open Systems Interconnection Basic Reference Model GB/T9387.3 Information processing system Open Systems Interconnection Basic Reference Model Part 3: Naming and addressing GB/T 15128
Information processing system Open Systems Interconnection Connection-oriented basic session service definition GB/T15129
Information processing system
Open Systems Interconnection Service Agreement
GB/T15696 Information processing system Open Systems Interconnection Connection-oriented presentation protocol specification ISO8824 Information processing system Open Systems Interconnection Abstract Syntax Notation One (ASN.1) specification CCITT recommendation X.410-1984 Message processing system: Remote operation and reliable delivery service 3 Terminology
Reference model terminology
This standard is based on GB 9387-88 is the basis for the concepts proposed in this paper, and uses the following terms defined therein: application-entity; b.
application-protocol-control-information application-protocol-control-information presentation-connection; presentation-entity 1 presentation-layer
presentation service presentation-service; presentation-service-access-point; presentation-service-data-unit; session connection; session service
transfer-syntax
concrete-syntax
$concrete-syntax:
open real-system real-open-system. Note: The abbreviations in Chapter 4 apply to the basic terms mentioned above. 3.2 Service Agreement Terms
This standard uses the following terms defined in GB/T 15129 and applicable to the presentation layer: service userserviceuscr
service providerservice-pravider!
Service primitive
service-primitive:
request;
indication;
response,
confirm;
nonconfirmed-service; confirmed-service, provider-initiated-service. 3.3 Naming and addressing terms
This standard uses the following terms defined in GB/T 9387.3: a.
talling-presentation-address called-presentation-address GB/T 15695-1995
c. responding-presentatin-address 3.4 Presentation service terms
This standard uses the following terms:
3.4.1 destructive
A service is destructive if the invocation of a service may cause the loss of undelivered data of other service primitives. 3.4.2 non-destructive A service is non-destructive if the invocation of a service does not cause the loss of data. 3.4.3 Abstract syntax Specification of application layer data or application coordination control information using notation rules that are independent of the coding technology used to represent these data or information. 3.4.4 Abstract syntax name abstract syntax name unambiguously identifies a name of an abstract syntax.
3.4.5 Transfer syntax name transfer syntax name unambiguously identifies a transfer syntax or a set of rules for generating a transfer syntax from a given abstract syntax. 3.4.6 Presentation data value information unit specified by an abstract syntax and transmitted by a presentation service. 3.4.7 Presentation context the combination of an abstract syntax and a transfer syntax.
Previous: (1) From the point of view of a user of a presentation service, a presentation context represents an environment in which presentation data values of an abstract syntax may be transmitted unambiguously (in the form of bit strings).
②) Presentation data values may contain fields where permitted by the abstract syntax, each field carrying a presentation data value conforming to (possibly different from) the abstract syntax.
③ From the point of view of a user of a presentation service, a presentation context represents a specific usage of an abstract syntax. Multiple presentation contexts may be defined for the same abstract syntax (corresponding to the same or different transfer syntaxes), and presentation data values transmitted in these contexts are delivered in these contexts respectively.
3.4.8 defined context set defined context set A set of presentation contexts agreed upon by the presentation service provider and two presentation service users for a communication. NOTE Inclusion of a presentation context in a defined context set means that the presentation context abstract syntax is acceptable to both presentation service users and that the cooperating presentation entities have agreed on an acceptable method of transferring the presentation context. 3.4.9 inter-activity defined context set A set of cousin contexts defined for a presentation connection when the session activity management functional unit is selected. Its initial value is the value of the defined context set when the presentation connection is established and it is subsequently modified by a P-ALTER-CONTEXT service statement issued outside the activity.
3.4.10 default context The default context is the default presentation context for the presentation service provider and two presentation service users on a given presentation connection and is always used for the user data parameter of the P-EXPEDITED-DATA service primitive. It is used for the user data parameter of other service primitives only when the defined context set is empty. NOTE: When no default context name is specified, an implicit default context is used. 3.4.11 functional unit logical grouping of services defined in this International Standard for the following purposes: - negotiated during presentation connection establishment, used on that presentation connection, and for reference by other standards.
3.4.12 disrupt
A service is said to disrupt another service if it causes the service primitives of the second service to be unable to be used as determined by its service procedures.
GB/T 15695—1995
3.4.13 X.410—1984 mode X.410-1984 mode A restricted mode of presentation layer operation that enables interworking with systems conforming to CCITT X.410-1984 Recommendation. 3.4.14 normal mode normal mode A mode of presentation layer operation that provides all the services of a presentation service. 3.4.15 initiator
a presentation entity or presentation service user that initiates the presentation connection establishment process. 3.4.16 responder
a presentation entity or presentation service user that responds to a presentation connection establishment proposal. 3.4.17 requestor
a presentation entity or presentation service user that initiates a specific action. 3.4.18 acceptor
a presentation entity or presentation service user that accepts a specific action. 3.4.19 presentation context identification identification of a specific presentation context at a conceptual service boundary. 4 Abbreviations
ASN.1 Abstract Syntax Notation (see ISO8824)DCS Defined Context Set
PCEP Connection Endpoint
PS Presentation Service
PSAP Service Access Point
PS User Presentation Service User
SS Session Service
5 Conventions
This standard uses the descriptive conventions defined in GB/T15129. 6 Overview of Presentation Services
6.1 Purpose
GB/T 15695-1995
Part I General
The presentation layer is concerned with the presentation of information transmitted by the open system (see GB9387-88). 6.2 Relationship with the Application Layer
Note: From the perspective of the presentation layer, the application layer can be described below. 6.2.1 The application protocol is specified by using the user data parameter of the presentation service primitive to transfer presentation data values between application entities (PS users).
6.2.2 The collection of presentation data value definitions associated with the application protocol constitutes an abstract syntax. For two application entities to communicate successfully, they must reach an agreement on the abstract syntax they are going to use. During the communication, they may decide to modify this agreement. Therefore, the set of abstract syntaxes in use can change. 6.2.3 The abstract syntax specification identifies the information content of a set of presentation data values. It does not identify the transfer syntax used when transmitting presentation data values between presentation entities, nor does it care about the local representation of presentation data values. 6.2.4 The presentation layer is set up to ensure that the information content of presentation data values remains unchanged during transmission. The cooperating application entities are responsible for deciding the set of abstract syntaxes to be used during communication and notifying the presentation entities of this agreement. After learning the abstract syntax set to be used by the application entity, the presentation entity is responsible for selecting a transfer syntax that is acceptable to both parties and that keeps the information content of the presentation data values unchanged. The presentation entity does not play any role in determining the abstract syntax set to be used by the application entity. 6.3 Relationship with the Session Layer
In order to provide the services described in GB9387-88 for the presentation service, the presentation entity supports the protocols used to enhance the OSI session service and provides access to the session service to the PS user so that it can utilize all session services, including negotiation and access to session functional units. The role of the presentation layer in providing this access includes expressing the presentation data values in the user data parameters of the session service primitives. Note: The presentation layer no longer enhances the dialogue control and data transfer functions provided by the session service. 6.4 Presentation Layer Characteristics
The presentation layer performs two functions on behalf of the PS user: negotiation of transfer syntax;
b. Transformation of transfer syntax.
The transfer syntax negotiation function is supported by the presentation protocol and provides the presentation context definition service. Transformation of transfer syntax is a function contained in the presentation entity and has no impact on the presentation protocol design. Note: ① Constraining and specifying the abstract syntax and transfer syntax supported by a specific open system is beyond the scope of the presentation service and presentation protocol standards. The syntax supported by the open system depends on the nature of the application involved in the system. ② In any open real system, the presentation data value conforms to the local H body syntax. The conversion of transfer syntax is the conversion between local specific syntax. 6-5 Syntax negotiation
When the PS user provides the abstract syntax name of the required transfer syntax, the transfer syntax is negotiated between the two presentation entities. The result of a successful negotiation is a presentation context composed of the combination of the named abstract syntax and the corresponding narrow transfer syntax. From the perspective of the PS user, the presentation context represents different special uses of the abstract syntax. Usually, the combination of abstract syntax and transfer syntax does not have to be unique. One or more transfer syntaxes may represent a specific abstract syntax, and one transfer syntax may represent one or more abstract syntaxes. 6.6 Information transmission
6.6.1 User information is carried by the user data parameter of the presentation service primitive. Each user data parameter contains one or more presentation data values. The order of these presentation data values remains unchanged during transmission. 6.6.2 If there is support for the abstract syntax used by the presentation context, the presentation data value can be constructed in this way so that it nests the presentation data values in other presentation contexts.
GB/T 15695 --1995
NOTE: The structure of the user data parameters of the presentation service primitives cannot be defined more explicitly at the service level. Any interface (if any) in the open real system shall define a specific form.
6.7 Presentation services are defined below
6.7.1 A presentation service definition provides services for presentation contexts to meet the information requirements of its users. One or more presentation context definitions fully describe the information transfer requirements of the presentation connection users. 6.7.2 There are two services for defining presentation contexts, namely P-CONNECT and P-AI.TER-CONTEXT services. The latter can also be used to delete presentation contexts that are no longer required. 6.7.3 Once a presentation context is defined, it is added to the DCS. The act of defining a presentation context makes the presentation context immediately available, which enables PS users to identify the set of presentation contexts required to fully describe the information flow between PS users. 6.7.4 If the DCS is empty, presentation service user data parameters can still be used to transfer presentation data values. In this case, all presentation data values come from the default context. This is only possible when the DCS is empty or P-EXPEDITED-DATA is used. When the P-EXPEDITED-DATA service primitive is used, presentation data values are transferred in the default context. The default context may be defined using the presentation connection establishment service or established by prior negotiation. It may not be redefined using any other presentation service. Presentation data values transferred using the P-EXPEDITED-DATA service are always taken from the default context. 6.8 1CS Management
If the presentation context management functional unit is not selected, the DCS does not change during the presentation connection and the remainder of clause 6.8 does not apply.
6.8.1 Context Management Functional Unit
6.8-1.1 If the context management functional unit is selected, the DCS may be changed during a connection using the P-ALTER-CONTEXT service. The presentation layer is responsible for ensuring that the DCS is identical at both ends of the presentation connection. The P-ALTER-CONTEXT service is therefore a confirming service. However, some destructive services may conflict with or supersede the P-ALTER-CONTEXT service.
6.8.1.2 If a P-RESYNCHRONIZE indication service primitive is received while waiting for a P-ALTER·CONTEXT confirm service primitive, the P-RESYNCHRONIZE service takes precedence and overrides the P-ALTER-CONTEXT service, indicating the DCS to the PS user. If a P-RESYNCHRONIZE request-queueSt service primitive is issued while waiting for a confirmation primitive for a P-ALTER-CONTEXT request, the P-RESYNCHRONIZE service takes precedence and overrides the P-ALTER-CONTEXT service, indicating to the PS user that the DCS
6.8-13 Interaction of the P-ACTIVITY-INTERRUPT service and the P-ACTIVITY-DISCARD service with the P-ALTER-CONTEXT service may cause a DCS dislocation and subsequent transfer of data in a presentation context unknown to one of the PS users. The PS user may use activity tokens and appropriate sequencing rules to avoid this. 6.8.2 Context recovery functional unit
6.8.2.1 The PS user may select the context recovery functional unit. If the context recovery functional unit is not selected, the DCS can only be changed by means of the P-ALTER-CONTEXT service and the remainder of clause 6.8 does not apply. If the context restore functional unit is selected, the presentation service provider will remember the DCS at specific points during the connection. If the PS user requests to return to one of these points, the TXCS is restored to the DCS that was in effect at that point.
6-8.2-2 P-RESYNCHRONIZE (restart) or (set) to a point known to the presentation service provider restores the DCS to the known TCS at that point. If the specified point is lower than those points known to the presentation service provider, the DCS is restored to the DCS defined when the presentation connection was established. If the specified point is higher than those points known to the presentation service provider, or the P-RESYNCHRONIZE service (discarded) is requested, the DCS remains unchanged. If an unknown point is specified (i.e., within the range of known points, but unknown to the presentation service provider), the presentation service provider will notify the PS user and will not change the DCS. 6.8.2.3 The DCS outside each activity is the inter-activity DCS. The inter-activity DCS is defined when the presentation connection is established and modified by the P-ALTER-CONTEXTrequest service primitive issued outside the activity. At the start of an activity, its initial DCS is equal to the inter-activity LXCS. Subsequent P-ALTER-CONTEXTrcquest service primitives issued within the activity change only the TCS of the activity. 6.8.2.4 P-ACTIVITY-END. P-ACTIVITY-INTERRUPT, P-ACTIVITY-DISCARD services cause the presentation service provider to restore the DCS to the inter-activity DCS. 6.8.2.5 The P-ACTIVITY-RESUMF service restores the DCS to a specified point in a specified activity (if known to the presentation service provider). Since this service is non-confirmed, it is possible that data may be received in an unknown presentation context. If this occurs, a PP-ABORT indication is issued to both PS users. 7 Service Services
Presentation services consist of a number of services. Each service is briefly described below. The services that make up the service are identified in Table 1. 7.1 Connection Establishment Service
The service provided by the connection establishment service allows a PS user to establish a presentation connection with another PS user. The service allows the PS user to establish the characteristics of the presentation connection by exchanging parameters, in particular: the selected presentation functional unit;
The characteristics of the initial DCS session connection;
Default context definition.
7.2 Connection Termination Service
The service provided by the connection termination service allows: a.
Orderly release of the presentation connection by the PS user in a non-destructive manner; b.
Termination of a presentation connection in a possibly destructive manner, which may be initiated by either of the two PS users or by the presentation service provider. 7.3 Context Management Service
The service provided by the context management service allows: a., according to the agreement between the two PS users and the presentation service provider, to add presentation contexts to the TCS, to assign an identifier to each defined presentation context, but the identifier has no meaning outside this presentation connection; h., to remove presentation contexts from the IXCS. 7.4 Information Transfer Services
The services provided by the information transfer services allow PS users to exchange information over a presentation connection. If the corresponding session functional unit is selected, these services allow token-controlled data, non-token-controlled data, privileged data, capability data and accelerated data. 7.5 Dialogue control services
If the corresponding session functional unit is selected, the services provided by the dialogue control services allow token management, synchronization, resynchronization, exception reporting and activity management, which are mapped to the corresponding session services 1. This standard only describes their relationship with other presentation services and their impact on other presentation services. In some cases, presentation services impose additional restrictions on the use of the service that directly calls the session service. The use of these services also affects the state of the presentation entity. The session service definition (see GB/T 15128) describes these services in more detail. Table 1 Summary of presentation services and their services and purposes Service name
Connection establishment service
P-CONNECT
Connection termination service
P-RELEASE
P U-ABORT
FP-ABORT
【Confirmed
Service Type
Confirmed
Unconfirmed
Provider Initiated
Connection Establishment
Connection Release
User-Initiated Abandon
Provider-Initiated Abandon
Context Management Service
P-ALTER-CONTEXT
Information Transfer Service
P-DATA
P-TYPED-DATA
Service Name
P-EXPEDITED-DATA
P-CAPABILITY-DATA
Session Control Service
P-TOKEN-GIVE
P-TOKEN-PLEASE
P-CONTROL GIVE
P-SYNC-MINOR
P-SYNC-MAJOR
P-RESYNCHRONIZE
PU-EXCEPTON-REPRT
PP-EXCEPTION-REPORT
P- ACTIVITY-START
P-ACTIVITY-RESUME
P-ACTFVTTY-END
P-ACTTVITY-INTERRUPT
P-ACTIVITY-DISCARD
GB/T 15695—1995
Continued Table 1
Service Type
Confirmed
Non-confirmed
Non-confirmed
Confirmed
Non-confirmed
Non-confirmed
Non-confirmed
Optional Confirmed
Confirmed
Confirmed
Non-confirmed
Provider Initiated
Non-delayed
Non-confirmed
Confirmed
Confirmed
Confirmed
Note: The purpose of the presentation service complies with the purpose of the corresponding conference service specified in CB/T 15128. 8 Functional Units
8.1 This standard uses functional units to identify PS user requests during presentation connection establishment. 8.2 There are two types of functional units
session functional units, as defined in GB/T 15128. They include: a.
core functional unit
-half-duplex functional unit;
duplex functional unit:
-accelerated data functional unit
secondary synchronization functional unit;
-primary synchronization functional unit;
resynchronization functional unit:
activity management functional unit;
negotiation release functional unit;
capability data unit,
exception functional unit,
privileged data functional unit.
context addition and removal
The possible selection of session functional units is subject to the restrictions imposed by the session service, see GB/T 15128. Note: The decision on which session functional units to use is made during the presentation connection establishment. GB/T15695-1995
h Presentation functional unit, corresponding to the services provided by the presentation layer, including! Core functional unit:
—Context management functional unit;
—Context recovery functional unit.
8.3 The core functional unit is always available, and it supports the transmission of information in the user data parameters of any service primitive in these selected functional units. The context management functional unit and the context recovery functional unit are optional, and their use is negotiable. If the context management functional unit is not selected on the presentation connection, the context recovery functional unit should not be selected. 8.4 If the PS user selects a session functional unit, the corresponding presentation services and functions are available to the PS user. 9 Quality of Service
The quality of service concept, related parameters and the way they are negotiated when the presentation connection is established are strictly consistent with the concepts, parameters and negotiation mechanisms defined in the Session Service Definition GB/T 15128 Note: Further extensions of this standard may establish the usage of quality of service parameters when deciding the transfer syntax to be used. 10 Presentation Service Primitives
GB/T15695-1995
Chapter 1 Service Primitive Definition
This standard uses the abstract model of layer service definition in GB/T 15129. This model defines the interaction between the PS user and the presentation service provider at two PSAPs, and transfers information between the PS user and the presentation service provider through service primitives that can carry parameters. The presentation service primitives listed in Table 2 are used to transmit information to and from the PS user. The sequence procedures for all services are specified in Section 11. NOTE: Except for P-TYPED-DATA and P-ATA, all other services that carry user data may not be able to exchange PS user data, depending on the transfer syntax used and the SS user data length restrictions supported by the layer session service. How the PS user is informed of this is a local matter. Table 2 shows the service primitives
Service primitives
P-CONNECT request
P-CONNECT indication
p-conNEtTesnae/rnfirmn
Call indication address
Callee indication address
Presentation context definition table
Default context name
Quality of service
Presentation requirements
Session requirements
Initial synchronization point sequence number
Initial identifier allocation
Session connection identifier
User data
Calling indication address
Callee indication address
Presentation context definition table
Presentation context definition result table
Default context name
Quality of service
Presentation requirements
Session requirements
Initial synchronization point sequence number
Initial token allocation
Session connection identifier
User data
Response presentation address
Presentation context definition result
Default context resultbzxZ.net
Quality of service
Presentation requirements
Session requirements
Initial synchronization point sequence number
Initial token allocation
Session connection identifier
User data
Service primitives
P-REI.FASF request/indicationP-RELEASE response/confirm
P-UJ-ARC>RT request/indicationP-P-ABORT indication
P-AI.TER-CONTEXT request
P-ALTER-CONTEXT indication
P-ALTER-CONTEXT response/confirmP-DATA request/indication
P-TYPED-DATA request/indieationP-EXPEDTTED-DATA request/indicatianP.CAPABILITY-DATA
reques1/indication/rcsponsc/conlirP-TOKEN-GIVE requcst/indicationP-TOKEN-PLEASE rcquest/indicationP-CON'TROL-GIVE requer/indicalionP SYNC-MINOR request/indicationP-SYNC-MINOR responHe /confirmP-SYNC-MAJOR request/indieationP-SYNC MAJOR respotisc/cunfirmP-RESYNCHRONIZE request
P-RESYNCHRONIZE indication
P-RESYNCHRONIZE: reRponse
GB/T 15695—1995
Continued Table 2
User data
User data
Provide old reason
Indicate context addition table
Indicate following text removal table
User data
Indicate previous text addition table
Indicate context table
Indicate context addition result table
User data
Indicate context addition result table
Indicate context deletion result table
User data
User data
User data
User data User data
User data
User data
Synchronization point sequence number
User data
Synchronization point sequence number
User data
User data
Resynchronization type
Synchronization point sequence number
User data
Resynchronization type
Synchronization point sequence number
Presentation context identification table
User data
Synchronization point sequence number
Service primitive
P-RESYNCHRONIZE response | | tt | response/confirmP-ACTIVITY-INTERRUPT
request/indication
CB/T 15695—1995
Continued Table 2
User data
Synchronization point sequence number
Representation context identifier table
User data
User data
Activity identifier
User data
Activity identifier
Old activity identifier
Synchronization point sequence number
Old session connection identifier
User data
Synchronization point sequence number
User data
User data
P-ACTIVITY-INTERRUPT response/confirmP-AGTIVITY-DISCARD request/indicatinnP-ACTIVITY-DISCARD respanse/eonfirm10.1 User Data Parameters
The information in the User Data Parameters of the P-EXPEDITED-DATArequest and indication service primitives is always taken from one or more Presentation Data Values in the default L context. The information in the User Data Parameters of all other Presentation Service Primitives is one or more Presentation Data Values taken from a context determined by the rules governing the DCS. Any embedded Presentation Data Values are taken from a Presentation Context determined by these rules:
If the LCS is empty and d does not hold, then each Presentation Data Value (including any nested Presentation Data Values) is taken from the default contexta.
If the DCS is not empty and no procedure is in progress that modifies the contents of the FCS, then each Presentation Data Value (including any nested Presentation Data Values) is taken from a Presentation Context in the DCS.c.If the procedure for a service primitive containing a User Data Parameter modifies the DCS, then each Presentation Data Value (including any nested Presentation Data Values) may be taken from a Presentation Context in the DCS resulting from the modification, or, if such modification results in an I If the XCS is empty, the default context is taken.
d. If a confirmation service primitive is waiting to confirm the proposed modification to the DCS, each presentation data value (including any nested presentation data values) is taken from a presentation context in the DCS that has not been proposed for deletion. If such a modification causes all presentation contexts to be unavailable, the user data parameter does not appear in the service primitive. 10.2P-CONNECT service
This service enables two identified PS users to start communicating. Its successful use will result in the establishment of a table connection with an initial DCS between them, which is used for their subsequent communications. This service is a non-destructive service. 10.2.1 StructurereRponse
GB/T 15695—1995
Continued Table 2
User data
Application data
User data
Provide old reason
Indicate context addition table
Indicate context removal table
User data
Indicate previous context addition table
Indicate context table
Indicate context addition result table
User data
Indicate context addition result table
Indicate context deletion result table
User data
User data
Application data User data
User data
User data
Synchronization point sequence number
User data
Synchronization point sequence number
User data
User data
Resynchronization type
Synchronization point sequence number
User data
Resynchronization type
Synchronization point sequence number
Presentation context identification table
User data
Synchronization point sequence number
Service primitive
P-RESYNCHRONIZE response | | tt | response/confirmP-ACTIVITY-INTERRUPT
request/indication
CB/T 15695—1995
Continued Table 2
User data
Synchronization point sequence number
Representation context identifier table
User data
User data
Activity identifier
User data
Activity identifier
Old activity identifier
Synchronization point sequence number
Old session connection identifier
User data
Synchronization point sequence number
User data
User data
P-ACTIVITY-INTERRUPT response/confirmP-AGTIVITY-DISCARD request/indicatinnP-ACTIVITY-DISCARD respanse/eonfirm10.1 User Data Parameters
The information in the User Data Parameters of the P-EXPEDITED-DATArequest and indication service primitives is always taken from one or more Presentation Data Values in the default L context. The information in the User Data Parameters of all other Presentation Service Primitives is one or more Presentation Data Values taken from a context determined by the rules governing the DCS. Any embedded Presentation Data Values are taken from a Presentation Context determined by these rules:
If the LCS is empty and d does not hold, then each Presentation Data Value (including any nested Presentation Data Values) is taken from the default contexta.
If the DCS is not empty and no procedure is in progress that modifies the contents of the FCS, then each Presentation Data Value (including any nested Presentation Data Values) is taken from a Presentation Context in the DCS.c.If the procedure for a service primitive containing a User Data Parameter modifies the DCS, then each Presentation Data Value (including any nested Presentation Data Values) may be taken from a Presentation Context in the DCS resulting from the modification, or, if such modification results in an I If the XCS is empty, the default context is taken.
d. If a confirmation service primitive is waiting to confirm the proposed modification to the DCS, each presentation data value (including any nested presentation data values) is taken from a presentation context in the DCS that has not been proposed for deletion. If such a modification causes all presentation contexts to be unavailable, the user data parameter does not appear in the service primitive. 10.2P-CONNECT service
This service enables two identified PS users to start communicating. Its successful use will result in the establishment of a table connection with an initial DCS between them, which is used for their subsequent communications. This service is a non-destructive service. 10.2.1 StructurereRponse
GB/T 15695—1995
Continued Table 2
User data
Application data
User data
Provide old reason
Indicate context addition table
Indicate context removal table
User data
Indicate previous context addition table
Indicate context table
Indicate context addition result table
User data
Indicate context addition result table
Indicate context deletion result table
User data
User data
Application data User data
User data
User data
Synchronization point sequence number
User data
Synchronization point sequence number
User data
User data
Resynchronization type
Synchronization point sequence number
User data
Resynchronization type
Synchronization point sequence number
Presentation context identification table
User data
Synchronization point sequence number
Service primitive
P-RESYNCHRONIZE response | | tt | response/confirmP-ACTIVITY-INTERRUPT
request/indication
CB/T 15695—1995
Continued Table 2
User data
Synchronization point sequence number
Representation context identifier table
User data
User data
Activity identifier
User data
Activity identifier
Old activity identifier
Synchronization point sequence number
Old session connection identifier
User data
Synchronization point sequence number
User data
User data
P-ACTIVITY-INTERRUPT response/confirmP-AGTIVITY-DISCARD request/indicatinnP-ACTIVITY-DISCARD respanse/eonfirm10.1 User Data Parameters
The information in the User Data Parameters of the P-EXPEDITED-DATArequest and indication service primitives is always taken from one or more Presentation Data Values in the default L context. The information in the User Data Parameters of all other Presentation Service Primitives is one or more Presentation Data Values taken from a context determined by the rules governing the DCS. Any embedded Presentation Data Values are taken from a Presentation Context determined by these rules:
If the LCS is empty and d does not hold, then each Presentation Data Value (including any nested Presentation Data Values) is taken from the default contexta.
If the DCS is not empty and no procedure is in progress that modifies the contents of the FCS, then each Presentation Data Value (including any nested Presentation Data Values) is taken from a Presentation Context in the DCS.c.If the procedure for a service primitive containing a User Data Parameter modifies the DCS, then each Presentation Data Value (including any nested Presentation Data Values) may be taken from a Presentation Context in the DCS resulting from the modification, or, if such modification results in an I If the XCS is empty, the default context is taken.
d. If a confirmation service primitive is waiting to confirm the proposed modification to the DCS, each presentation data value (including any nested presentation data values) is taken from a presentation context in the DCS that has not been proposed for deletion. If such a modification causes all presentation contexts to be unavailable, the user data parameter does not appear in the service primitive. 10.2P-CONNECT service
This service enables two identified PS users to start communicating. Its successful use will result in the establishment of a table connection with an initial DCS between them, which is used for their subsequent communications. This service is a non-destructive service. 10.2.1 Structure
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