1、BRITISH STANDARD BS ISO 14827-2:2005 Transport information and control systems Data interfaces between centres for transport information and control systems Part 2: DATEX-ASN ICS 03.220.01; 35.240.60 BS ISO 14827-2:2005 This British Standard was published under the authority of the Standards Policy
2、and Strategy Committee on 12 December 2005 BSI 12 December 2005 ISBN 0 580 47177 2 National foreword This British Standard reproduces verbatim ISO 14827-2:2005 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee EPL/278, Road tr
3、ansport informatics, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European development
4、s and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entit
5、led “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance
6、 with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 63 and a back cover. The BSI copyright notice displayed in this document indi
7、cates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 14827-2:2005(E)INTERNATIONAL STANDARD ISO 14827-2 First edition 2005-11-01 Transport information and control systems Data interfaces between centres for transport information and
8、control systems Part 2: DATEX-ASN Systmes de commande et dinformation des transports Interfaces de donnes entre les centres pour systmes de commande et dinformation des transports Partie 2: DATEX-ASN BS ISO 14827-2:2005ii BS ISO 14827-2:2005 iii Contents Page Foreword iv Introduction v 1 Scope . 1 2
9、 Normative references . 2 3 Terms and definitions. 3 4 Symbols and abbreviated terms . 5 5 Implementation considerations. 6 6 Data exchange procedures 6 6.1 General data packet procedures . 7 6.2 General file procedures 7 6.3 Sessions 8 6.4 Requesting information 11 6.5 Publication of information .
10、12 Annex A (normative) Data packet structures 16 Annex B (normative) Data dictionary . 23 Annex C (normative) Value domains 45 Annex D (normative) DATEX-ASN over internet protocols 55 Annex E (normative) Protocol requirements list 56 Annex F (informative) Implementation guidance 61 Annex G (informat
11、ive) Advantages of DATEX-ASN 62 BS ISO 14827-2:2005 iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees.
12、 Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Interna
13、tional Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Stan
14、dards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subje
15、ct of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14827-2 was prepared by Technical Committee ISO/TC 204, Intelligent transport systems, Working Group 9, with the collaboration of: European Road Transport Telematics Implementation Coordination
16、Organization (ERTICO); Comit Europen de Normalisation (CEN); American Association of State Highway and Transportation Officials (AASHTO); Institute of Transportation Engineers (ITE); National Electrical Manufacturers Association (NEMA). ISO 14827 consists of the following parts, under the general ti
17、tle Transport information and control systems Data interfaces between centres for transport information and control systems: Part 1: Message definition requirements Part 2: DATEX-ASN v Introduction In the 1980s and 1990s, transport networks became increasinigly congested and computer technologies we
18、re deployed to more efficiently manage the limited transport network. As these systems were deployed, it became more important to integrate nearby systems to properly provide the required services. One of the first efforts to standardize the interface between transport control centres was a European
19、 Union effort led by the DATEX Task Force. In May 1993, this group was established as a horizontal activity to coordinate the diverging developments which were ongoing within the framework of the Advanced Transport Telematics (ATT) Programme. Within the ATT Programme, three different data exchange s
20、ystems were developed: INTERCHANGE, EURO-TRIANGLE and STRADA. The group produced a set of basic tools to meet existing needs, including a common data dictionary, a common set of EDIFACT messages and a common geographical location referencing system. The initial solution provided a common interface w
21、hich satisfied the basic requirements of existing systems, and was named the Data Exchange Network (DATEX-Net) Specifications for Interoperability. During the initial efforts to deploy this International Standard, there was a growing sense that the message structure should be better organized and sh
22、ould be defined using Abstract Syntax Notation One (ASN.1) rather than EDIFACT. ASN.1 presents a standard notation for the definition of data types and values. A data type is a class of information (e.g. numeric, textual, still image or video information). A data value is an instance of such a class
23、. ASN.1 defines several basic types and their corresponding values, and rules for combining them into more complex types and values. These types and values can then be encoded into a byte stream according to any of several standardised encoding rules. Efforts to standardize communications between tr
24、ansport control centres were also underway in other parts of the world. In 1997, all of these efforts began to merge, with the United States developing the initial draft of the ASN.1 structures for the Data Exchange in Abstract Syntax Notation (DATEX-ASN). These structures, called data packets, were
25、 then placed within a procedural context and submitted to the ISO standardization process. A portion of the submittal dealt with the specification of messages. As this portion of the document could apply to various protocols, it was placed in ISO 14827-1 Message definition requirements. The remainde
26、r of the original submittal formed the basis of the application layer protocol and was placed in this part of ISO 14827. Thus, this part defines only one way to implement the messages that are specified in the format defined by ISO 14827-1. This resulting International Standard supports existing and
27、 foreseen data exchange needs using modern design concepts. Due to the flexibility required by the rapidly developing transport information and control systems (TICS) environment, this part of ISO 14827 uses a very generic structure. Thus, although initially intended to be an International Standard
28、for TICS, it is flexible enough to be used for virtually any data exchange. ISO 14827-1 explains how to define end-application messages that are to be exchanged between centres for TICS. This definition has been designed to be relatively generic to the selected protocol (e.g. DATEX-ASN, CORBA, etc.)
29、 This part of ISO 14827 provides the specification of the Data Exchange protocol in ASN.1 (DATEX-ASN) used to exchange data between central systems. DATEX-ASN was the first protocol standardized because: the development of DATEX-Net could be leveraged, and there was sufficient market interest to per
30、form the required technical work. BS ISO 14827-2:2005blank1 Transport information and control systems Data interfaces between centres for transport information and control systems Part 2: DATEX-ASN 1 Scope DATEX-ASN allows different systems to exchange relevant data. This is contained in end-applica
31、tion messages. Each end-application message is defined as either a “subscription” or a “publication” according to the format as specified in ISO 14827-1. DATEX-ASN defines how these end-application messages are packaged to form a complete data packet and also defines the rules and procedures for exc
32、hanging these data packets. Systems using DATEX-ASN are free to implement additional end-application functionalities according to the user requirements. A DATEX-ASN network comprises a certain number of systems, an example of which is provided in Figure 1. Key 1 weather system 2 traffic management s
33、ystem 3 transit management system 4 emergency management system 5 information service provider Figure 1 An example of a DATEX-ASN network BS ISO 14827-2:20052 Each system can be viewed as consisting of the interfaces, as shown in Figure 2: Key 1 application interface 2 operator interface 3 communica
34、tion interface 4 database interface 5 communications cloud 6 client system 7 server system Figure 2 System interfaces This part of ISO 14827 deals only with the communications interface. It has been designed to meet the unique requirements of TICS; however, it has been designed in a generic fashion
35、and thus could be used for other data exchanges as well. Systems implementing this part of 14827 sometimes operate simultaneously as a client and server, using multiple sessions. The communications cloud between the two systems may be complex or simple. 2 Normative references The following reference
36、d documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4217, Codes for the representation of currencies and funds ISO 8824-
37、1, Information technology Abstract Syntax Notation One (ASN.1) Part 1: Specification of basic notation ISO 8825-2, Information technology ASN.1 encoding rules Part 2: Specification of Packed Encoding Rules (PER) ISO 14827-1, Transport information and control systems Data interfaces between centres f
38、or transport information and control systems Part 1: Message definition requirements BS ISO 14827-2:20053 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 14827-1 and the following apply. 3.1 connectionless transport profile service that provides end-
39、system to end-system communications without any connection set-up EXAMPLE UDP/IP. 3.2 connection-oriented transport profile service that allows one end-system to exchange a continuous stream of data with another end-system, the data of which is guaranteed to be delivered in the same order in which i
40、t was sent without any duplication NOTE This service is typically achieved by first establishing a connection, then sending the data, and finally terminating the connection. EXAMPLE TCP/IP. 3.3 data element syntactically formal representation of some single unit of information of interest (such as a
41、 fact, proposition, observation, etc) about some (entity) class of interest (e.g. a person, place, process, property, concept, association, state, event, etc.) 3.4 datagram entity of data containing enough information to be routed from source to destination without relying on previous network config
42、uration EXAMPLE IP datagram. 3.5 datagram publication DATEX-ASN publication (reply) that is sent directly over the given transport profile, in contrast with a file publication 3.6 destination system or device to which the information in the data packet is intended to be sent 3.7 encoding rules rules
43、 which specify the representation during transfer of the values of ASN.1 types NOTE 1 Encoding rules also enable the values to be recovered from the representation, given knowledge of the type. NOTE 2 For the purpose of specifying encoding rules, the various referenced type (and value) notations, wh
44、ich can provide alternative notations for built-in types (and values), are not relevant. 3.8 Ethernet specific combination of physical and data link layer protocols as defined in IEEE 802.3 that allow multiple systems to gain access to a shared medium and communicate with one another BS ISO 14827-2:
45、20054 3.9 file data storage object, which may be located on any file system such as a hard-disk, a floppy-disk, a RAM-drive, etc. 3.10 file publication DATEX-ASN publication (reply) that is stored on the servers file system until the client has an opportunity to retrieve it via a file transfer proto
46、col, in contrast with datagram publication 3.11 guaranteed delivery DATEX-ASN mechanism in which the client acknowledges the receipt of a publication (reply) 3.12 heartbeat data packet sent to indicate that the sending system is still alive and communicating 3.13 maximum turn-around time maximum amo
47、unt of time a system is given to provide an appropriate response to the incoming data packet 3.14 origin system or device which was the source for all of the information in the data packet NOTE In many cases, this will be the same as the sender, but could be different. For example, a bridge (or prox
48、y agent) may translate between protocols; in this case the bridge (or proxy agent) would be the sender, while the system generating the data would be the origin. 3.15 port logical channel in a communications system NOTE UDP and TCP use port numbers to multiplex data packets from a variety of applica
49、tions onto a single communications system. 3.16 response time-out period maximum duration a system is required to wait for a response data packet prior to assuming that the previously sent data packet was never received by the other application 3.17 sender system which created and sent the DATEX-ASN data packet 3.18 session period of time during which a client and a server exchange multiple data packets 3.19 silently drop to ignore a da
