JPH02224047A - Encoding/decoding system - Google Patents

Abstract

PURPOSE:To execute the processing which does not depend on an application service and a service primitive by encoding in advance an identifier of a protocol data element used by the application service, and generating in advance a skeleton of a transfer syntax arranged in an appearance order at every service primitive. CONSTITUTION:Since a skeleton of a transfer syntax 6 is generated in advance, an encoding processing of an identifier for identifying a protocol data unit (PDU) data element can be omitted, and since the transfer syntax 6 is generated by converting only the contents of the PDU data element, the encoding processing can be executed at high speed. With regard to the time of decoding, as well, decoding of a value of the PDU data element can be executed without decoding the identifier of the encoded PDU data element, and a value converted to a primitive can be set directly, therefore, decoding can be executed at high speed. As for the service which cannot fix and allocate the skeleton 8, it will suffice that an encoding processing/decision processing module of the identifier of a variable part is generated only with regard to the variable part, therefore, a program scale can be suppressed to the minimum.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to encoding of a protocol data unit (PDU) defined by Abstract Syntax Notation ASN,1 into a transfer syntax, and its inverse conversion (decoding). Regarding the method.

[Conventional technology]

ASN, 1 (Abs 1-Raku 1- Syntax No Chee John One: Abstraei 5yntax
NotationOne) is an abstract syntax notation used to define the format of protocol data units (PDUs) used in the application and presentation layers in O8I. The format of I'DU written using the ASN and l notation is called an abstract tank sentence, and the ASN
A byte string converted from an abstract syntax using the encoding rules defined in , 1 is called a transfer syntax.

The P D tJ provided on each system consists of multiple data elements, each of which has an ASN.

According to the encoding rules of J, the data is converted into three elements: an identification P for identifying which element in the PDTJ, the length of the data element, and the content of the data element. At this time, the content of the data element itself is also converted into the data specified by the ASN. Encoded 11 DU is not decoded;! 5. As mentioned above, when transmitting a PDU to or receiving it from another system, it is necessary to encode/decode the PDU into a transfer syntax according to the encoding rules of ASN, i.

Conventionally, the encoding/decoding method based on ASN, 1 encoding rule & Hitoi C is (1) Information Processing Society of Japan 35th (late 1988) National Conference, pages 533 to 534, ↑n
H (Processing Society of Japan No. 6 (first half of 1988) National Conference, pages 999 to 1000, Information Processing Society of Japan Research Report Multimedia Communication S and Distributed Processing 36-...F (1988)
,2,),9) Pages 1 to 8, and (2) Information Processing Society of Japan Research Report Maruji,-De,ia Communication and Distributed Outside @39-
4 (19B8, 9.16) pages 1 to 8 i b=.

In the document 1 (1), the PDU format and encoding method described by ΔSN, 1 are developed into a Kozuchizukuri table (Zoloto full internal representation) [,・every τ°, Will Watazakoma be able to apply PDU day/evening elements to applied services from the top? Convert data into a format that can be referenced (intermediate format), and in the presentation layer,
The transfer syntax is converted to the transfer syntax while referring to the table and the intermediate format. Similarly, when decoding the transfer syntax, it is converted to the intermediate format while referring to the table in the notification layer, and then in the application service. System-specific 1
' Convert again to D U data element 2 In this method, the process of converting the P D U data element passed from the upper level to the intermediate format must be created individually for each application Levis, but The conversion process to the transfer syntax can be performed in common to all application services in the presentation layer. In the document (2) above, conversion to the intermediate format and
No table references are performed, and the Huni encoding processing program is provided exclusively for each service and handles the presentation layer processing in (1) above (7,
DU day/evening elements are directly transferred or converted. Similarly, the decoding of the transfer syntax is passed directly to the upper layer by a decoding processing program dedicated to each application service.
Create puller element 14. To go.

[Problems to be solved by the invention] Stated in the prior art (i) ζJ5, application of code/decoding processing) processing that is common to the nosentation layer regardless of navigation input. For this reason, the purpose is 7 meters.
The format for receiving and transmitting PDU data elements to each application service module shall be agreed between the 1,000 joules processed by each application service module and the upper application program that uses this application service. - It is necessary to convert it once to a common intermediate format on the -visual side. The encoding/decoding processing module in the presentation layer has the following functions:
It is possible to convert between the intermediate format and the transfer syntax without any need. However, interposing an intermediate format increases encoding/decoding processing overhead.

It is difficult to apply to real-time processing environments where response time is severely constrained.

The above-mentioned conventional technology (2) directly performs encoding/decoding processing, seven joules, and imbrication for each application service, and directly converts between the I'DU data element 7 transfer syntax passed from the upper layer. Therefore, the code 4i conversion/decoding registration can be performed efficiently and can be applied to a real-time processing environment. Only 1, di! In addition, since it is necessary to create a program for each application service child, there is a problem that the amount of time required to create a program increases.Also, there is a need to change the protocol specifications for 5 application services. Sometimes it is necessary to change the program.

An object of the present invention is to provide an encoding/decoding method that has high speed applicable to a real-time processing environment, and has versatility that can be commonly used in various application services.

[Means to solve the problem]

Convert PDUs used in each application into transfer syntax? ", the number of data elements and the settings for the transfer syntax M1
The code of the identifier representing each data element can be specified by the service primitive number J of the application service. Therefore, in order to achieve the above purpose, a transfer syntax skeleton is created for each bis primitive in which the identifiers of the PDU data elements of the PDU used in each application service are encoded in advance and arranged in the order of appearance. At this time, for services where the transfer syntax identification = T-sign changes depending on the contents of the PDU data element, the script is made with the identifier of the part where the change occurs (variable part) in a constant state. 6. The encoding/decoding process is built into each application service, and the PDU data passed from the higher level is・Conversion between data elements and transfer inscriptions is performed directly by converting the skeleton. In the skeleton with the variable parts of each service primitive, processing is performed using a variable element processing module dedicated to each service primitive, converting the format of the content of the PDU data element and incorporating it into the transfer syntax. Processing is common to each application service and service primitive.

[Effect]

During encoding processing, a corresponding skeleton is selected corresponding to the service primitive of each application service, and small data elements are embedded in the PDTJ according to the format of the transfer syntax described in the skeleton. Since the corresponding variable element processing module is selected and the identifier is encoded, the PDU data element passed from the higher level can be converted into a direct transfer syntax.

Similarly, during the decoding process, select the appropriate skeleton corresponding to the service primitive of each application service.
In accordance with the format of the transfer syntax described in the skeleton, the PDU white data element embedded in the transfer syntax is directly fetched. If a variable element is included, the corresponding variable element processing module is selected and the identifier is decoded, so the conversion from the transfer syntax to the PDtJ summary to be passed to the upper level is performed directly in line λ.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 is a diagram showing the configuration of an embodiment of the encoding/decoding system according to the present invention. 1 (i-i, 1-2) is a control device for computers and machine tools such as robots, 2 (2-1
, 2, -2) is a user-created application program located above the application layer in 08th block, 3 (3-1, 3-3) is a protocol processing module of one application service of the application layer, and 4 (
4-1, 1-2) are lower protocol processing modules that perform protocol processing below the application layer.
, 5-2) is a data exchange format called a primitive agreed between the application program 2 and the application layer protocol processing module 3, and 6 (6-1, 6-2) is the data exchange format agreed between the application program 2 and the application layer protocol processing module 3. Processing module 4. This is a data exchange format called a transfer inscription, which was agreed upon in I'J. 7 (''/-1°7-2) is the primitive 5, in the application layer protocol processing module 3.
An encoding/decoding processing module 8 (8-1° 8-2) that performs format conversion between the transfer syntaxes 6 is a skeleton of the transfer syntax used during encoding/decoding.

The primitive 5-1 passed from the application program 2-1 to the application layer protocol processing module 3-1 is converted into a transfer syntax 6-1 by the encoding processing module 7-1. Joule 4-1- is
The passed transfer syntax 6-1 is converted into a PDU for own protocol processing.
as data to the destination station 1 via the transmission line 11.
Lower protocol processing module 4-2 on 0-2! Send this. The lower protocol processing module 4-2 processes the application layer protocol 1-2 included in the own protocol processing PDU.
The data portion 6-2 regarding protocol processing is passed to the application layer protocol processing module 3-2. The application layer protocol processing module 3-2 converts the format into a primitive 5-2 using the decoding processing module 7-2 and passes it to the application program 22. Through this series of processing, the application layer protocol processing module 3-2 is created in the environment on the station 10-1. Primitive 5-1
, is restored to a primitive 5-2 that can be analyzed by the application program 2-2 on the station 10-2 in a different environment.

FIG. 7 shows one format of the primitive. The format of the primitive is defined by the application layer protocol processing module, but each primitive has its own format.

The content ELMi of the PDU day element is set depending on the environment of each station.

Figure 8 shows one format of the transfer syntax.The transfer syntax includes an identifier IDx for identifying the type of PDTJ data element set in the primitive, a length Lx of the PDU data element to be created for each R identifier ID, and the length Lx of each PDU data element. Converted to a format common to the environment]
, the contents of the PDU data element (ELMj,)'. The format and contents of transfer syntax regarding the same service primitive are the same in all environments.

FIG. 9 shows one form of a transfer syntax skeleton.

The skeleton is ASN. Service primitive units 13 for protocol processing are created according to the protocol specifications described by No. 1. The skeleton is an identifier IDX used when converting a PDU data element into a transfer syntax.
Identifier ID, identifier modification range Qx that expresses the length of the separately created PDU data element using position information on the skeleton
, m PT corresponding to separate works) U Element setting position information P indicating where in the primitive the content of the data element is set, data type conversion rules for the content of the PDU data element (α, β...・). Create the skeleton in advance using any method, and then use the professional [...
It can be referenced in units of cols and services.

First, an example of purchasing an encoding/decoding processing module will be described with reference to FIG. The encoding/decoding processing module has a skeleton, which is referenced when performing processing, in memory or the like. The encoding/decoding processing module has a skeleton selection processing (7a) having means for selecting a skeleton (8a) to be used when creating and decomposing a transfer syntax from a skeleton group (8), and an encoding processing function. Transfer syntax synthesis processing (7b) with decoding processing function, data element setting processing (7c) with decoding processing function, setting of variable part in skeleton/
It consists of a data type conversion process (7o) having a determination processing function. Processing other than variable element processing can be commonly used for encoding/decoding of each protocol and service.

Hereinafter, an example of the encoding method will be described with reference to FIG. 2, FIG. 3, and FIG.

The encoding/decoding processing module that has received the primitive 5 selects the corresponding skeleton 8a from the skeleton group 8 using the skeleton selection module (Stop
1 a) Perform transfer syntax synthesis processing using the selected skeleton group (Stop 2a).

The outline of the transfer syntax synthesis process is shown below. First, an identifier is selected from the selected skeleton, and based on the element setting position information regarding the identifier, it is checked whether or not the content of the PDU data element set in the primitive is captured. When importing the contents of a data element, the contents of the data element (EL Ml/E
LMI%) is obtained, the data type is converted according to the data type conversion rules (5top3a), and the content of the data element (ELMI'/ELM11') obtained by conversion 1 is set in the transfer syntax storage buffer. Furthermore, the length of the content of the converted data element (Li=/Lc) is encoded according to the identifier modification range information in the skeleton, and is set together with the skeleton identifier (Step 4 a).

If it is not necessary to import the contents of the data element in the primitive, use the above process to encode the length (Q&) according to the ra-specific modification range information and only set the length (La) and identifier (IDa). , when fetching the contents of a data element from within a primitive, if the element is not set at the specified position, the process ends as an abnormal termination.

The process is shown when an identifier indicating a variable value is set in the skeleton. The identifier in the skeleton is a variable value (x)
If so, the processing module for variable part setting is selected from the variable element processing group (Step 5 a), and the corresponding variable element setting processing refers to the contents of the data element (ELMz) set in the primitive. , identifier 1. Check whether this value can be encoded. If encoding is possible, encode the content of the data element (ELM2.) into an identifier (IDx), encode the length according to the identifier modification range information N (Qx) in the skeleton, and set it in the transfer syntax buffer ( S
top 4 a). If the content of the data element (ELM2) is a value that cannot be encoded, the process is terminated as an abnormal termination.

During encoding, the above processing is performed for the number of elements set in the skeleton, the identifier shown in the skeleton, the identifier modification range,
Process in ascending or descending order according to conversion rules. The identifiers in the skeleton are arranged in the order of the identifiers that appear when the transfer syntax is created, so when the transfer syntax is created, the content of the data element is embedded in the specified position.

Next, an example of a decoding method will be described with reference to FIGS. 1, 4, and 5.

The encoding/decoding processing module that has received the transfer syntax 6 selects the corresponding skeleton 8a from the skeleton groups 1 to 8 using the skeleton selection module (Stsp
lb), data element setting processing is performed using the selected skeleton (Stap 2b).

An overview of data element setting processing is shown. First, the transfer syntax is divided into the identifier IDi and the content E L of the PDU data element according to the identifier qualification range (Ωa@Qbg 12□Qc).
Decompose into M a '. The retrieved identifier is compared with the skeleton internal identifier, and the retrieved length L is compared with the skeleton internal identifier modification range, and if they match, it is checked whether a PDU data element is set. If the content of the data element is an identifier (ID b/ID c), convert the data type according to the conversion rules in the skeleton. Top 3
b) Contents of data elements (ELM 1/ELMa)
is set in the primitive according to the element setting position information (
Stop4b). If the decomposed identifier does not match the information in the skeleton, the process is terminated as an abnormal termination.

Indicates processing when an identifier indicating a variable value is set in the skeleton.The identifier in the skeleton is a variable value (X)
If so, a processing module for variable part determination is selected from the variable element processing group (Step 5b), and the corresponding variable element determination processing is performed using the identifier (IDx) obtained during disassembly.
Check if can be used as a variable element. If available, the identification T-(IDx) is set to the data element content (E
LMz) and set in the primitive according to the element setting position information (Step 4b). If the identifier ID that was not obtained during disassembly is inappropriate, the process is terminated as an abnormal termination.

At the time of decoding, the identifiers shown in the skeleton correspond to the number of elements set in the skeleton for the above processing.

The identifiers in the skeleton are processed in ascending order according to the identifier qualification range and conversion rules.Since the identifiers in the skeleton are arranged in the order of the identifiers that appear when the transfer syntax is decomposed, when creating a primitive, the contents of data elements are extracted from the transfer syntax. Perform processing.

As described above, this embodiment has the advantage that encoding/decoding processing can be performed at high speed.

〔Effect of the invention〕

According to the present invention, since the transfer syntax scale 1 is created in advance, the encoding process of the identifier for identifying the r'DU data element can be omitted, and only the contents of the PDU data element are converted and transferred. Since the syntax is created, the encoding process can be performed at high speed. Also during decoding, the value of the PDU data element can be decoded without decoding the encoded identifier of the PDU data element.

Since the converted value can be directly set in the primitive, decoding can be performed at high speed. 6 For services where skeletons cannot be fixedly allocated, it is only necessary to create an encoding/judgment processing module for the identifier of the variable part only for the variable part. , program scale can be kept to a minimum.

Since the skeleton of the transfer syntax is created in accordance with the protocol description of the PDU, when changing the protocol, two customers can be transferred by simply changing the skeleton. Furthermore, since changes to the program are limited to the encoding processing/judgment processing module of the variable portion, management becomes easier.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a configuration example of an encoding/decoding processing module in the present invention, FIG. 2 is an operation explanatory diagram showing an example of encoding processing, and FIG. 3 is a flowchart showing an example of encoding processing. , FIG. 4 is an operation explanatory diagram showing an example of the decoding process, FIG. 5 is a flowchart showing an example of the decoding process,
FIG. 6 is a block diagram showing the functional configuration of an embodiment of encoding/decoding processing according to the present invention, and FIG. 7 is an explanatory diagram showing an example of the configuration of Primizoib passed to the encoding/decoding processing module. , FIG. 8 is an explanatory diagram showing an example of a transfer syntax created by the encoding/decoding processing module, and FIG. 9 is an explanatory diagram showing an example of the structure of a skeleton used during encoding/decoding. 1... Computer and control device, 2... Application program. 3° performance layer protocol processing module, 4...lower protocol processing module, 5...primitive, 6
... Transfer syntax, 7... Encoding/decoding processing module, 8... Transfer syntax skeleton, 10... Node. 1.1...Transmission line. Figure 1

Claims (1)

[Claims] 1. The protocol data element of the application service is assigned ASN.
A process of converting the transfer syntax into a transfer syntax according to the encoding rules defined in ASN.1, and converting the transfer syntax into ASN. In the process of converting into protocol data elements according to the decoding rules specified in 1, the identifiers of the protocol data elements used by the application service are encoded in advance, and a skeleton of the transfer syntax arranged in the order of appearance is created in advance for each service primitive. An encoding/decoding method characterized by making only the content of the protocol data element the information to be encoded/decoded in the transfer syntax, thereby enabling processing independent of application services and service primitives. .