ASN.1 Complete
A technical guide and reference to ASN.1, a standard language often used to describe data protocols.
TABLE OF CONTENTS ASN.1 Complete
Chapter 2: Introduction to ASN.1
(Or: Read Before You Write!)
Summary
The best way of learning any language or notation is to read some of it. This chapter presents a small example of ASN.1 type definitions and introduces the main concepts of
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built-in key-words,
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construction mechanisms,
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user-defined types with type-reference-names,
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identifiers or "field-names", and
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alternatives.
There is a reference to "tagging", which is discussed in more detail in Section II.
This chapter is intended for beginners in ASN.1, and can be skipped by those who have already been exposed to the notation.
2.1 Introduction
Look at Figure 2.1. The aim here is simply to make sense of the data-structure it is defining the information that transmission of a value of this structure would convey.
Figure 2.1 is an "artificial" example designed to illustrate the features of ASN.1. It does not necessarily represent the best "business solution" to the problem it appears to be addressing, but the interested reader could try to invent a plausible rationale for some of its more curious features. For example, why have different "details" been used for "uk" and for "overseas" when the "overseas" case can hold any information the "uk" case can? Plausible answer, the "uk" case was in version 1, and the "overseas" was added later when the business expanded, and the designer wanted to keep the same bits-on-the-line for the "uk" case.
This example is built-on as this book proceeds, and the scenario for this "Wineco protocol" appears in Appendix 1 with the complete protocol in Appendix 2.
ASN.1...
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