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SAE J2630 - Converting ATIS Message Standards from ASN.1 to XML


This Fact Sheet was written on April 14, 2006. The status of the standard at the time was: Published in December 2003.

This Fact Sheet was last verified on October 07, 2009

 Check the ITS Standards Search to see if there has been subsequent development activity.

Overview

This standard, SAE J2630 - Converting ATIS Message Standards from ASN.1 to XML, defines a set of rules for transforming an Abstract Syntax Notation One (ASN.1) message set definition into an eXtensible Markup Language (XML) schema that is fully consistent with the existing ASN.1 message set. The conversion rules defined in the standard include rules for beginning and ending the XML schema, rules for converting ASN.1 types (e.g., Integer, String, Enumerated, Bit String, Octet String, Object Identifier (OID), and constructed types), rules for handling optional elements, commonly repeated elements, comments, and use of XML Namespaces to handle types that are defined in other schemas. Each conversion rule is supported by examples and additional discussion is provided for the more complex rules. Additional type definitions (e.g., Binary, Numeric String) that were developed specifically for SAE J2354 - Message Set for Advanced Traveler Information System (ATIS) are also documented in this standard. An example conversion is provided at the conclusion of the standard that illustrates proper use of the rules to convert a sample ASN.1 message definition into an equivalent XML schema.

What are these standards for?

The conversion rules defined in SAE J2630 - Converting ATIS Message Standards from ASN.1 to XML are used to develop a stand-alone XML schema that is fully consistent with an existing ASN.1 information model. Although the rules defined in SAE J2630 were initially developed in order to produce an XML schema for SAE J2354, other ITS message set developers may choose to use these rules to produce XML schemas from their existing ASN.1 definitions. By using the consistent set of conversion rules that are defined in this standard, a standards developer will produce an XML schema that is more consistent with XML schemas developed by other ITS standards developers using the same set of rules. It should be noted that the conversion is only guaranteed in one direction (i.e., from ASN.1 to XML) and is not designed to be bidirectional. Use of the rules defined in this standard can also save time since the developer does not have to develop their own conversion rules.

Who uses them?

The SAE J2630 - Converting ATIS Message Standards from ASN.1 to XML standard is primarily intended for use by ITS standards developers who need to transform an existing ASN.1 message set definition into an XML schema. While the primary audience is standards developers, system integrators may also make use of the standard to support conversion of their ASN.1 definitions into XML schemas. System integrators are advised to use the XML schemas that are defined in the published versions of the ITS Message Set standards (e.g., SAE J2354) and only use the SAE J2630 rules to do their own conversion when such a standard XML schema is not otherwise available.

How are they used?

Although each conversion rule is carefully defined and well documented in the standard, the manual conversion of a large ASN.1 message set definition to an equivalent XML schema using the conversion rules would be a laborious process and subject to human error. The ITS Standards developers have used a software tool called "Mini-Edit" to automate the conversion from ASN.1 to XML consistent with the rules defined in SAE J2630 - Converting ATIS Message Standards from ASN.1 to XML. Mini-Edit has been actively maintained since SAE J2630 was published and actually implements a few additional conversion rules that were identified after SAE J2630 was published. Any person engaged in the development or deployment of ITS standards is allowed to use Mini-Edit in its basic form. FHWA is currently supporting maintenance of the Mini-Edit tool and it may be obtained from http://www.itsware.net/miniedit/readme.htm free of charge. Alternatively, a developer could write their own software program that implements the conversion rules and produces XML schemas from ASN.1. The XML schemas that are produced by this conversion process are normally balloted and published in ITS Message Set standards, such as SAE J2354 and IEEE 1512 (Family of Standards for Incident Management Message Sets). If the conversion rules are used by a system integrator, then the XML schema that is produced could be published in an Interface Control Document, as was done for the TMDD XML schema that was generated using SAE J2630 for the Condition Acquisition and Reporting System (CARS) program.

Scope

The SAE J2630 - Converting ATIS Message Standards from ASN.1 to XML standard was developed specifically to support conversion of the ASN.1 used in the SAE J2354 message set into a stand-alone XML schema for traveler information. To ensure that the translations could be used successfully for other ITS Standards, the IEEE 1512 standards family, Standards for Traffic Management Center-to-Center Communications, and Transit Communications Interface Protocols (TCIP) message sets were also considered during development of SAE J2630. Note that this standard was developed specifically to support conversion of the ASN.1 that was developed for ITS Standards. It does not support conversion of the entire ASN.1 language. This standard is distinct from other standards that have been developed that define XML Encoding Rules (XER) for ASN.1 and rules for mapping XML schemas into ASN.1.

Related documents

The following ITS standards are related and should be considered when using this family of standards:

The following standards and documents, while not part of the ITS standards, should also be considered when using this standard:

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