12 Apr 2011 LaForge   » (Master)

Finally: A parseable MAPv1 ASN.1 specification

After way too much work in extracting the ASN.1 text from word documents, learning about the differences in pre-1990 ASN.1 and pre-1990 TCAP with their respective current-day counterpart, some futile attempts with the incomplete ASN.1 grammar files available for ANTLR3, I have finally dedicated the entire day to manually convert the MAPv1 from ETSI TS 09.02 3.10.0 (1994) to work with present-day TCAP and present-day ASN.1 syntax.

The result not only passes the syntax and semantic checker, but it is accepted by the Erlang asn1ct. It has not been tested/validated against any test data so far. Just in case anyone else needs a 'working' version of MAPv1 some 20 years after it was created, I have published the result here: http://cgit.osmocom.org/cgit/asn1_docextract/tree/output/3.10.0

Any bugfixes/improvements/complaints are obviously welcome.

Now I just need to figure out how to properly work with the ROS/ROSE CONTRACT class and TCAP APPLICATION-CONTEXT class to formally describe the various application contexts, their respective MAP operations and associated application context versions. It's actually quite a bit surprising that the ETSI/3GPP don't specify this formally in 29.002. The information is contained in the human-readable part of the document, but not in the formal ASN.1 notation. I wonder why...

Syndicated 2011-04-12 02:00:00 from Harald Welte's blog

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