Effnet ASN.1 5G Toolset

Introduction

Abstract Syntax Notation.1 (ASN.1) is a formal notation or a language used to describe data structures. With ASN.1, the data structures are described independent of programming language used and they can be encoded and decoded independent of platforms used to send, receive and process them. This makes ASN.1 a versatile method to describe data structures in telecommunications and networking.

ASN.1 is a joint standard of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T).

A simple example, describing a message with a parameter name and an integer value.

Message ::= SEQUENCE {
    parameter PrintableString,
    value INTEGER (0..65535)
}

Using that ASN.1 message description, we can encode the following message:

hitchhiker Message ::= {
    parameter "meaningoflife",
    value 42
}

The message, encoded in UPER format as per the ASN.1 description becomes:

0D DB 97 0E ED 3B B3 EF CD B3 4E 6C A0 05 40

This message can be transmitted to the receiving side. The receiving side can, using the same ASN.1 Message description, easily decode that message back to the original format without ambiguity.

ASN.1 is used by protocol developers to represent data structures which are defined as a part of a standards document. The main advantage of using ASN.1 to represent data structures is that it is independent of programming language or platform as well as it is both human and machine readable.

ASN.1 functional overview

An ASN.1 Toolset contains:

a compiler that can parse the ASN.1 files that contains the data structure notation, generate the equivalent declaration in a programming language (like C or C++) and generates the encoding and decoding functions based on the previous declarations. In other words, a compiler that compiles ASN.1 notation to generate data structure declaration in a programming language of choice and generate functions for encoding and decoding of those data structures.
libraries to encode and decode pre-defined basic types such as integers (INTEGER), booleans (BOOLEAN), character strings (IA5String, UniversalString...), bit strings (BIT STRING), etc., and constructed types such as structures (SEQUENCE), lists (SEQUENCE OF), choice between types (CHOICE), etc. Subtyping constraints can be also applied on any ASN.1 type in order to restrict its set of values. Several types of encoding methods can be used e.g. packed encoding rules (PER), basic encoding rules (BER) etc.

Specification

The Effnet ASN.1 5G Toolset:

uses modern C++
is highly secure full type safe code without pointers
provides better performance from compiler optimization
is a portable and robust (high quality) implementation
delivers high performance (fewer CPU cycles per message encoding/decoding) to support high packet rates
supports PER (both aligned and unaligned)

The toolset is currently delivered as ASN.1 C++ encoder/decoder run-time libraries.

5G component support

3GPP Release 15
- RRC
- F1AP
- E1AP
- NGAP
- XnAP and
- NRPPa specifications
O-RAN
- E2AP specification

The Effnet ASN.1 5G Toolset will be continuously updated as the related standards evolve.

ASN.1 5G component support