Category Archives: ASN1C

V2X API Updated for SAE J2735

We’ve updated our V2X API for the latest revision of SAE J2735, revision 202007.

About Objective System’s V2X API

The V2X API is available for C++, Java, and C#.  It supports encoding/decoding V2X messages defined by SAE J2735 and ETSI standards.

The Python and Go wrappers enable easy conversion between binary and text encodings by providing a simple Python and Go interface on top of the C++ API.

For more, go here.


TAP 3 DLL Software for ASN1C v74

The Objective Systems TAP 3 DLL product provides a library of C functions for encoding and decoding messages formatted according to any of the following specifications:

  • TAP (Transferred Account Procedure) versions 0309 through 0312, as defined in the TD.57 documents.
  • RAP (Returned Account Procedure) version 0105-0312, as defined in the TD.32 document.
  • NRTRDE (Near Real Time Roaming Data Exchange) version 0201, as defined in the TD.35 document.

This product has recently been upgraded with the following new features:

  • C code generated with ASN1C v74.
  • Mechanisms for encoding to XML and decoding from XML.
  • Mechanisms for encoding to JSON and decoding from JSON.
  • A Python wrapper.
  • A TAP3VE GUI utility for examining TAP 3 messages, similar to our ASN1VE product.

You can find out more about the TAP 3 DLL software and download an evaluation distribution file here:
TAP 3 DLL download page

Optimization, Licensing, and Performance

Users evaluating our ASN1C SDK frequently find they don’t get the encoding or decoding performance they hoped for.  The libraries we provide for evaluation have less-than-optimal performance for two reasons: they are not optimized and they include license checking overhead. Customers who need to evaluate performance characteristics can request access to optimized libraries, but without doing that, what are some reasonable expectations?

We recently did some performance analysis to help a potential customer evaluate performance. The analysis was for decoding of LTE RRC messages using C++. We used ASN1C 7.4, the statically-linked ASN1C libraries, and Visual Studio 2019. Due to possible variations in specifications, data sets, and hardware, I don’t report absolute measurements here, but rather relative measurements of elapsed wall clock time.

Non-optimized, limited (license-checked) library (baseline) 100%
Non-optimized (debug), unlimited (license-check free) library 72%
Optimized, limited (license-checked) library 47%
Optimized, unlimited (license-check free) library 20%
Optimized, unlimited (license-check free) library, with code generation changes (see below for details) <2% (8.5% of the time for the same library without the code generation changes)

In this test, we found that the optimized, unlimited library used roughly 20% of the time used by the non-optimized, limited library provided with the evaluation SDK (that’s an 80% reduction in elapsed time).

In this particular case, we did some further experimentation to see what could be done with the generated code to get even better performance using the optimized, unlimited library. We found that by removing some generated diagnostics-related code and using dynamic arrays instead of linked lists, we achieved a tremendous further performance boost. (We generated code using the -dynamicArray option and compiled it with _COMPACT defined). By doing this, we found the time used was less than 2% of the baseline, and only 8.5% of the time used by the optimized, unlimited library.

ASN1C v7.4 Release for 2020 Features Python Code Gen

We are pleased to announce a new major release of ASN1C for 2020, version 7.4.

The main new feature in this release is the capability to generate Python encoders and decoders. Currently supported is generation of code for the BER/DER and JSON (JER) encoding rules. The BER support includes options to generate forward encoders using indefinite lengths and also includes support for parsing and formatting 3GPP TS 32.297 headers as used in standard 3GPP CDR formats.

The new capability provides for generation of 100% Python code, not wrappers around platform-specific DLL’s or shared object files.

We plan to add support for PER, OER, and XER later this year.

In addition to Python, other features in the new release include:

  • Support for 5G ASN.1-based protocols as well as 5G NAS (3GPP TS 24.501)
  • Support for Visual Studio 2019 in the Windows versions
  • The capability to use ASN1C project files created with the GUI from the command-line

Further information can be found in the documentation on the product support page.

ASN1C kits available for older Linux 64-bit systems using older glibc and ld libraries

A new ASN1C Linux 64-bit evaluation kit is now available for ASN1C version 7.3.3 to address problems reported by users with the current package. One problem reported was when executing the ASN1C binary, an error similar to this may be displayed: “version ‘GLIBC_2.12’ not found”. A second problem was in linking with libraries in the package in which an error to the effect of “unrecognized relocation” or “bad value” would be reported. This is because our binaries are now built with a newer version of glibc and ld (such as, currently, glibc 2.23 and ld/binutils 2.26). Older systems that have glibc versions such as 2.12 will fail to build with these libraries.

This new package contains executable files and libraries built with an older version of glibc.

The description of the existing package on our download page has been changed to:

  • Linux Ubuntu 16.04 (x64) 64-bit, glibc 2.23

The new package is

  • Linux Centos 6.5 (x64) 64-bit, glibc 2.12, no GUI

Note that in both of these cases, even though we have listed the specific Linux distribution used, the packages should work on any reasonably up-to-date Linux distributions such as SUSE, Fedora, Debian, etc. The only factor in determining which one to use would be the version of glibc.

Also note that the package that uses the older glibc does not contain the ASN1C GUI as it required the newer glibc version be available.

To check which version of glibc your system is currently using, enter the command “ldd –version”. This will print the version of ldd and glibc, with output similar to the following:

  • ldd (GNU libc) 2.12