Platform Specific Model

Platform Specific Model

Introduction

Data exchange among centres is a baseline service for implementing ITS Services: Data Delivery and Collaborative ITS Services implementation need for their interoperability to be implemented according to certain specification based on fully described interfaces: the Functional Exchange Profiles implementing Push & Pull Exchange Pattern aim to guarantee timely and reliable delivery of information, based on defined level of services and user requirements depending on application level, so a variety of options to implement exchange are described which enable several interoperable exchange patterns with required features to fully satisfy user requirements; from snapshot pull / push to simple push to stateful push also considering service request /service feedback collaborative ITS services business scenario, which allow interoperable exchange among any number of interconnected and collaborating to implement traffic management and traffic information services orchestrated among several ITS actors.

This chapter aims to define and describe the requirements on XML messages to implement messages using XML profile B, specifically to be used in platform specific implementations using SOAP Web Services to enable EN 16157 (DATEX II) XML coded messages, for Snapshot Pull, Snapshot Push, Simple Push and Stateful Push, plus Collaborative ITS Services such as Simple CIS and Stateful CIS exchange patterns with relative functional exchange profiles as described by ISO CEN Exchange 2020 PIM.

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Figure 1 Relationship between exchange related documents

The message structure defined int his chapter refers to “Basic Exchange Data Model” and derived data dictionary defined in ISO CEN Exchange 2020 PIM, Annex C , which is implemented in XML Schema by the DATEX II methodology defined in EN 16157-1.

The relationship between this chapter and other standards in the ISO 14827 series is as follows:

ISO 14827-3 defines XML Messages Profile A formats to implement XML messages for profile A requirements.

This document is not intended to conflict with existing standards on interfaces of data exchange among ITS centres.

Scope

This document, based on ISO/TS 19468 Methodology and platform independent models for exchange involving traffic control centres, traffic information centres and service providers, aims to fully specify a platform specific method to implement data exchange among centres based on SOAP, supporting EN 16157 standard series (DATEX II), for push pull data delivery and service request/feedback collaborative ITS services.

Note

Rules and procedures for exchanging data-packets in lower communication layers are out of scope of this document. These functionalities can be implemented using generic protocols defined in the industrial standards. However, this document defines how to use these protocols.

References

The following documents are referred to in the text in such a way that some of or all their content constitutes requirements 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.

Exchange 2020 PIM

EN 16157-1:2019, Intelligent transport systems - DATEX II data exchange specifications for traffic management and information - Part 1: Context and framework

EN 16157-7:2019, Intelligent transport systems - DATEX II data exchange specifications for traffic management and information - Part 7: Common data elements

Terms and definitions

For the purposes of this document, the terms and definitions given in CEN ISO TS 19468 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at http://www.electropedia.org/

Symbols and abbreviated terms

For the purposes of this document, the abbreviation of terms given in CEN ISO TS 19468 (under revision) and the following apply

UCS - Universal Multi-octet Coded Character Set UTF - UCS Transfer Format

Exchange modelling framework

The model driven approach defined in CEN/ISO TS 19468 is resumed in Figure 2.

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Figure 2 Model Driven Approach from 19468

This document describes the mapping rules in order to implement specific platform Push and Pull and CIS FEP+EP based PIM in SOAP web services technology PSM. PIM level description of FEP+EP is detailed in ISO TS 19468 clauses, which are referenced in this document.

Web Services provides standard means of interoperating between different software applications, running on a variety of platforms and/or frameworks.

Definition (W3C - Web Service architecture - http://www.w3.org/TR/2004/NOTE-ws-arch-20040211/): « A Web Service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the Web Service in a manner prescribed by its description using SOAP messages, typically conveyed using HTTP with an XML serialisation in conjunction with other Web-related standards. »

Web services definitions offer several options. Table 1 shows the options chosen by the PSMs described in this document.

Web Service Options Decision
Discovery Not dynamic : UDDI is not used, the Web Services are described in this DATEX II document which is the reference for development
Security The security set-up has to be decided by the Supplier, should be negotiated with the Clients, and is outside the scope of this specification
Encryption This has to be agreed between the Supplier and the Client, before starting data exchange

Table 1 Web Services options

Web Services PSM mapping of FEP+EP PIMs

Platform Specific Model (PIM) specification to implement FEP+EP PIM based on WS SOAP technology consists in mapping the abstract UML messages ( invocation methods and data types ) defined at FEP+EP PIM level as UML collaboration and sequence diagrams in ISO TS 19468 clauses to the corresponding SOAP WSDL methods and data structure.

Data Delivery FEP+EP PSM definition

Overview of Data Delivery PSM definition

The following clauses express requirements for implementation of Data Delivery business scenarios FEP+EP which are fully described at PIM level in Exchange 2020 PIM by referencing their exchange agent and relative interfaces.

Note

A system can be both a client and a supplier of another system simultaneously, defining multiple separated exchange contexts (e.g. set of exchange nodes defined to exchange information in a specific business scenario with a specified EP+FEP).

Profile B “Snapshot Pull” SOAP webservices PSM definition

The profile B “Snapshot Pull” SOAP web services implementation is defined according to the “Snapshot Pull” FEP + EP PIM description which is described at Snapshot Pull Section of Exchange 2020 PIM, where “Snapshot Pull” exchange system functional characteristics and features implementation are fully described.

In the Profile B “Snapshot Pull” SOAP webservices exchange interface, the SOAP WSDL supplier method to implement pullSnapshotData shall be the WSDL method named “pullSnapshotData” which shall not require any input and shall return a “MessageContainer” information XML message data structure. Messages are implemented by SOAP protocol adding SOAP envelope information. The corresponding WSDL file is given in Annex A of the present document, xsd definitions for MessageContainer are fully described in Annex B

Profile B “Snapshot Push” SOAP webservices PSM definition

The profile B “Snapshot Push” SOAP web services implementation is defined according to the “Snapshot Push” FEP + EP PIM description which is described at Snapshot Push section of Exchange 2020 PIM, where “Snapshot Push” exchange system functional characteristics and features are fully described.

In the Profile B “Snapshot Push” SOAP webservice exchange interface, the SOAP WSDL client method to implement putSnapshotData shall be the WSDL method named “putSnapshotData” which shall accept as input a “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

Messages are implemented by SOAP protocol adding SOAP envelope information.The corresponding WSDL file is given in Annex A of the present document, xsd definition for MessageContainer and Exchange Information are fully described in Annex B .

Profile B “Simple Push” SOAP webservices PSM definition

The profile B “Simple Push” SOAP web services implementation is defined according to the “Simple Push” FEP + EP PIM description which is described at “Simple Push” Section of Exchange 2020 PIM, where “Simple Push” exchange system functional characteristics and features are fully described.

In the Profile B “Simple Push” SOAP webservices exchange interface:

  • the SOAP WSDL client method to implement putSnapshotData shall be the wsdl method named “putSnapshotData” which shall accept as input a “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement putData shall be the wsdl method named “putData” which shall accept as input a “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement keepAlive shall be the wsdl method named “keepAlive” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

Messages are implemented by SOAP protocol adding SOAP envelope information. The corresponding WSDL file is given in Annex A of the present document, xsd definition for MessageContainer and Exchange Information are fully described in Annex B .

Profile B “Stateful Push” SOAP webservices PSM definition

The profile B “Stateful Push” SOAP web services implementation is defined according to the “Stateful Push” FEP + EP PIM description which is described at “Stateful Push” section of Exchange 2020 PIM, where “Stateful Push” exchange system functional characteristics and features are fully described.

In the profile B “Stateful Push” SOAP webservices exchange interface:

  • the SOAP WSDL client method to implement openSession shall be the wsdl method named “openSession” ” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement closeSession shall be the wsdl method named “closeSession” ” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement putSnapshotData shall be the wsdl method named “putSnapshotData” which shall accept as input a “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement putData shall be the wsdl method named “putData” which shall accept as input a “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement keepAlive shall be the wsdl method named “keepAlive” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

Messages are implemented by SOAP protocol adding SOAP envelope information. The corresponding WSDL file is given in Annex A of the present document, xsd definition for MessageContainer and Exchange Information are fully described in Annex B.

Collaborative ITS Services FEP+EP PSM definition

Overview of “Collaborative ITS Services” PSM definition

The following clauses express requirements for implementation of Collaborative ITS Services business scenarios FEP+EP which are fully described at PIM level in Exchange 2020 PIM by referencing their exchange agent and relative interfaces.

Note

A system can be both a CIS requester and a CIS provider for another CIS requester simultaneously, defining multiple separated CIS exchange contexts (e.g. set of exchange nodes defined to exchange information in a specific business scenario with a specified EP+FEP).

Profile B “Simple CIS” SOAP webservices PSM definition

The profile B “Simple CIS” SOAP web services implementation is defined according to the “Simple CIS” FEP + EP PIM description which is described at “Simple CIS” section of Exchange 2020 PIM, where this exchange system functional characteristics and features are fully described.

In the profile B “Simple CIS” SOAP webservices exchange interface at service provider side:

  • The SOAP WSDL method to implement putCISServiceRequest shall be the wsdl method named ” putCISServiceRequest” which shall accept as input an “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

In the profile B “Simple CIS” SOAP webservices exchange interface at service requester side:

  • The SOAP WSDL method to implement putCISServiceFeedback shall be the wsdl method named “putCISServiceRequest” ” which shall accept as input an “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

Messages are implemented by SOAP protocol adding SOAP envelope information.

The corresponding WSDL file is given in Annex A of the present document, xsd definition for MessageContainer and Exchange Information are fully described in Annex B .

Stateful CIS

The profile B “Stateful CIS” SOAP web services implementation is defined according to the “Stateful CIS” FEP + EP PIM description which is described at “StatefulCIS” Section of Exchange 2020 PIM, where this exchange system functional characteristics and features are fully described.

In the profile B “Simple CIS” SOAP webservices exchange interface at service provider side:

  • the SOAP WSDL method to implement putCISServiceRequest shall be the wsdl method named ” putCISServiceRequest” which shall accept as input an “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement openSession shall be the wsdl method named “openSession” ” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement closeSession shall be the wsdl method named “closeSession” ” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.
  • the SOAP WSDL client method to implement keepAlive shall be the wsdl method named “keepAlive” which shall accept as input an “ExchangeInformation” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

In the profile B “Simple CIS” SOAP webservices exchange interface at service requester side:

  • The SOAP WSDL method to implement putCISServiceFeedback shall be the wsdl method named “putCISServiceRequest” ” which shall accept as input an “MessageContainer” XML message data structure and shall return an “ExchangeInformation” XML message data structure.

Messages are implemented by SOAP protocol adding SOAP envelope information. The corresponding WSDL file is given in Annex A of the present document, xsd definition for MessageContainer and Exchange Information are fully described in Annex B .