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Introduction
Supported Standards
The following standards are supported:
- ASN.1 according to ITU X.680, X.681, X.682 and X.683, 1997 version
- BER (Basic Encoding Rules) according to ITU X.690, 1997 version
- Basic PER (Packed Encoding Rules) according to ITU X.691, 1997 version, both aligned and unaligned variants.
Restrictions are listed in the Known Limitations chapter in the Release Guide.
Overview
The Abstract Syntax Notation One (ASN.1) is a notation language that is used for describing structured information that is intended to be transferred across some type of interface or communication medium. It is especially used for defining communication protocols.
SDL is suitable for specifying the semantic actions of a protocol, something that ASN.1 does not cover.
By using ASN.1 data types in the implementation of your application, you will optimize your development process. The following list displays some of the advantages of ASN.1:
- ASN.1 is a standardized, vendor-, platform- and language independent notation.
- A vast number of telecommunication protocols and services are defined using ASN.1. This means that pre-defined ASN.1 packages and modules are available and can be obtained from standardization organizations, RFCs, etc.
- When ASN.1 data types are transmitted over computer networks, their values must be represented in bit-patterns. Encoding and decoding rules determining the bit-patterns are already defined for ASN.1. The SDL Suite supports BER and PER encoding.
The SDL Suite support for ASN.1 consists of two major parts:
- An ASN.1 to SDL translator, ASN.1 Utilities, which allows you to use the ASN.1 types in your SDL systems.
- ASN.1 coders that will automatically encode your SDL values to bit-patterns and decode from bit-patterns to SDL values.
You can access the ASN.1 coders from SDL diagrams as well as from the C code.
Before you start the encoding and decoding steps, you must perform some preliminary steps. These are presented in Tutorial: Using ASN.1 Data Types.
Related Documents
Additional information about using ASN.1 and about encoding and decoding can be found in:
http://www.ibm.com/rational |
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