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Introduction


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.

As ASN.1 is widely popular, the SDL Suite allows you to translate ASN.1 data types to SDL and to encode/decode ASN.1 data types.

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:

Implementation of ASN.1

When importing ASN.1 data types to your SDL system, you need to translate the ASN.1 definitions to SDL. The SDL Suite does this for you using a tool called ASN.1 Utilities. This tool is automatically invoked when you analyze your SDL system.

However, having the ASN.1 data types translated to SDL is not enough to include them in your application. If you are going to transfer application-generated information on computer networks, the values of the data types must be encoded. When transferring signals in or out of your SDL system, you must also create the interface between the environment and the system.

Thus, the process of implementing ASN.1 data types can be divided into three separate steps:

  1. Creating the abstract syntax
  2. Creating the transfer syntax
  3. Compiling the application

The definitions of the abstract syntax and the transfer syntax is presented below.

Abstract Syntax

The basic idea is to transport some type of information between two nodes using protocol messages. The abstract syntax is defined as the set of all possible messages that can be transported. To create the abstract syntax you must:

Transfer Syntax

The transfer syntax is the set of bit patterns that represents the abstract syntax messages with each bit pattern representing just one value. The rules determining the bit-patterns are called the encoding rules.


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