1. © 2004Kizoom 1 SIRI - Service Interface for Real Time Information (CEN-OO278181 ) http://www.siri.org.uk http://www.siri.org.uk 27- 29 Cursitor Street London, EC4A 1LT nick_knowles@kizoom.com Siri 0.1g v3.6c

2. © 2004Kizoom 2 Topics Overview –Key Points –Motivation –Underlying standards Specific Functional Services Transport & Communications What do you need to do to Implement Siri? Roadmap –Some Possible Future Work Items

3. © 2004Kizoom 3 SIRI Overview

4. © 2004Kizoom 4 SIRI – Introduction Real-time Server-to-Server Services for Public Transport –Defines a Service Interface for exchanging real- time information of public transport networks. –Complements an underlying static information model for network and timetable description (TRIDENT,VDV, TransXChange) –Provides information on any change on the timetabled information, from original publication to the actual & predicted transport running times.

5. © 2004Kizoom 5 Gene Pool

6. © 2004Kizoom 6 Based on Underlying Standards –Public Transport Data TransModel : Terminology, model (isomorphic) VDV 453, 454, Trident, RTIG-XML –Real systems & experience! GML, WGS84 –Technology XML, XSD WS-Soap, WS-PubSub  Web Service enabled UML, ISO 24531, RFC Participants –Germany (VDV453, VDV 454) –France (Trident, TransModel) –UK (RTIG-XML, Trident, TransModel) –Denmark, Sweden, Norway, (PubTrans) –Czechoslovakia

7. © 2004Kizoom 7 SIRI Key Points Approach –Defines Functional services (real-time) –Defines an independent communication layer (may be reused elsewhere) –SIRI does not define the underlying object structure and data-model (Stop Points, Lines, Route, etc.) : Assumed to be TransModel compliant Practical / Pragmatic –SIRI is a tool box, well designed for an incremental implementation –It is not a Panacea …. –Compromises to accomodate real systems Includes compromises to facilitate migration

8. © 2004Kizoom 8 Motivation - Uses of SIRI Services Rapid growth in real-time info - makes Public Transport more efficient to operate & more attractive to use. –Provision of Real time Service Information to Passengers. At Stop, On board, tethered & mobile internet –Provision of Information to Journey Planners. Real-time augmented –Facilitating Connections for Passengers. –PT Fleet and Network Management. –General Business Communication. E.g. Adherence to schedule Growth of mobile & internet –On-line, real time data. Roaming! –Ubiquitous embedded computing

9. © 2004Kizoom 9 Motivation – Linking up Orchestrating Multiple Actors in federated systems –Passenger information services involving multiple providers Connection/interchange information Stop Point/Station operated by several transport operators etc. –Services between different operators Single PT line – several operators Connection management –Services with other content providers To provide information to content providers To get information from content providers

10. © 2004Kizoom 10 Motivation - Standards Value to Passenger Transport Executives and Authorities / Operators as Customers –Open, modular architectures & supplier independence. –Protection of investment. –Efficient tender specification criteria. Value to Suppliers –European economies of scale & markets. –Reduced complexity & deployment costs –More reuse, Cheaper integration –Simplified tendering, quality differentiator. Value to Both –Enables new types of services –European economies of scale –Lowers costs - creating new markets –Modern, Modular, scaleable architectures –Harnesses open internet standards

11. © 2004Kizoom 11 The SIRI Specifications SIRI Documents (Completed 2005) –Technical Standard Part 1: Context and Framework Part 2: Communications Infrastructure Part 3: Functional Service Interfaces –Supporting XML Schema – W3C.XSD Modular package structure, one per service Support WSDL /SOAP binding using same xsd schema Migration path from existing standards –Country Profiles & Guidance Notes

12. © 2004Kizoom 12 Web Site http://www.siri.org.uk

13. © 2004Kizoom 13 SIRI Approach & Services Separation of Concerns –Transport layer is separate –Web Service architecture (http &/or SOAP…..) –SIRI General Communications Services Common to all types of Functional Service Robust, scaleable, architecture for Real-Time Tuneable for efficient deployment –SIRI Functional Services Timetables & Timetable Changes Stop Events (Arrivals & Departures) Vehicle Movement Connection Protection (Timetables, Events) General Informative Messages

14. © 2004Kizoom 14 Support Different Operation Models The same Interface s can be used for different operational models

15. © 2004Kizoom 15 Support Different Environments Able to optimise for different operational characteristics –High/Low bandwidth –Fast/slow processors –Hi/Low traffic –Large/small networks –Sparse /dense usage –Central or distributed Evolvable –Able to implement on different generations of technology –Allow modular, incremental implementation: roadmap

16. © 2004Kizoom 16 SIRI Functional Services

17. © 2004Kizoom 17 SIRI Timetable Services Production Timetable (PT) –Distribute latest timetable Schedule to AVMS AVMS to client Estimated Timetable (ET) –Distribute latest timetable including real-time Cancellations, additions, short working Realtime-predictions

18. © 2004Kizoom 18 SIRI Stop Services Stop Timetable (ST) –Distribute latest timetable Stop Centric Timetables Provisions Clients with latest data. Stop Monitoring (SM) –Real time Arrival & Departure Boards Arrivals, Departures, pass-throughs At stop, onboard, away

19. © 2004Kizoom 19 SIRI Connection Services Connection Timetable (CT) –Distribute planned interchanges Stop Centric Provisions Clients. Connection Monitoring (CM) –Connection management –Guaranteed connection support

20. © 2004Kizoom 20 SIRI General Message Services General Message (GM) –Exchange Structured Messages Simple or embedded structures (eg TPEG, Trident etc) Situation, operational, and general info messages

21. © 2004Kizoom 21 PT Systems & SIRI Interfaces aa Generic model of PT operations, showing exchange points for RTI

22. © 2004Kizoom 22 Example 1: Hamburg Federated Modes & Regions

23. © 2004Kizoom 23 Example 2: Copenhagen Integrator

24. © 2004Kizoom 24 Example: Isle de France Hybrid

25. © 2004Kizoom 25 Transport & General Communications

26. © 2004Kizoom 26 Transport & Communications Common Protocols for all SIRI Functional Services –Independent of Functional Message Content –Based on new Web services standard Ws- PubSub, Ws-Address etc (W3C) –Communications Transport Independent XML + http POST, WSDL SOAP Binding

27. © 2004Kizoom 27 SIRI Communications Layer Common to all Functional Services

28. © 2004Kizoom 28 Common Communications Services General Functions Common to all SIRI Service Types –Subscription Management –Recovery & Restart –Access Controls – Who is allowed to access? –Versioning – Allows distributed upgrades –Discovery – Which systems have which data? Some Capabilities are Optional

29. © 2004Kizoom 29 Communications Framework Patterns Alternate Patterns of Interaction 1.Request/Response vs. Publish/Subscribe Choose for scaleability & responsibility 2.Direct Delivery vs. Fetched Delivery Allows efficient implementation choices 3.Notification Mediation Reduces traffic for publish subscribe –Last Update, Change Threshold, –Subscriber Groups

30. © 2004Kizoom 30 Interaction 1- Request/Response

31. © 2004Kizoom 31 Interaction 2- Publish/Subscribe

32. © 2004Kizoom 32 Delivery - Direct

33. © 2004Kizoom 33 Delivery - Direct & Fetched

34. © 2004Kizoom 34 Mediation Filtering of Data & Notifications to Reduce data traffic –Incremental Data Changes: Only send data changes since last update –Change threshold Only notify if change is more than a certain amount –Grouping of subscriptions One notification for changes to many subscriptions in a group

35. © 2004Kizoom 35 Mediation - Efficiency Reducing Traffic

36. © 2004Kizoom 36 Mediation Interaction of simple patterns can be quite complex.

37. © 2004Kizoom 37 SIRI What do you need to do to implement SIRI ?

38. © 2004Kizoom 38 How to Implement SIRI #1 Select the parts of SIRI you need, –Timetables, Stop Monitoring, etc –Discovery, Access Control Select your transport protocol (SOAP, HTTP post, XML anything else…) –Select additional Web Service (encryption, authentication, etc.) Select non-mandatory fields (XSD) Define any needed extensions –Embeddable any data types

39. © 2004Kizoom 39 How to Implement SIRI #2 Agree Local Reference data –Identify partipant « peers » –Line Ids –Stop Point Ids (and Stop Point kind…) –Connections Ids –Supported values (ServiceCategory, ProductCategory, VehicleFeature) –Geospatial Coordinate System

40. © 2004Kizoom 40 How to Implement SIRI #3 Agree Local Communication & Mediation Options –Interaction Patterns Request / Response Publish / Subscribe –Delivery Pattern Direct only (or Fetched delivery DE) Multiple Subscriber Delivery –Transport & Comms http POST / WSDL –Recovery Heartbeat for PubSub Acknowledgement of notifications – or not –Mediation Simple or multiple subscriber filters, “Stop VisitNumber”

41. © 2004Kizoom 41 SIRI Further Roadmap

42. © 2004Kizoom 42 SIRI – Status Final Draft Awaiting Vote Next WG Meeting Feb 6/7 2006 Possible Work Items Interoperability / Datex? Some Services live already!

43. © 2004Kizoom 43 Possible Additional Work Items Real-time Facility Changes Service FR –Allows changes to availability of facilities and equipment of stop, vehicle and service to be exchanged in real time. This can be used for example to communicate equipment changes affecting impaired access to PT such as lift or escalator changes. Information is of use to real-time journey-planning and alert services. Should consider interchange aspects. Situation/Event Structured Incident model UK/FR –Enhance GMS to have preferred structured incident model for describing disruptions to services, model relates to SIRI, Based on TPEG + TransModel Control Actions Server Interface SE –Service for distributing control actions amongst participants, for example for coordinating management of late services. Traffic Status / Prioritisation Interface for UTMC UK/DE –Allows real-time public transport management systems to exchange information with road UTMC systems, eg to provide real time delay information a road speed information to the road traffic management system, or to allow for the exchange of signal priority options.

44. © 2004Kizoom 44 SIRI Data Content Exchange Behaviour Transport Protocol well-defined interactions with XML schema representations Mainstream Internet HTTP POST, SOAP. defined XML Schema For payload XML Http Post SOAP TransModelWS-PubSub http get ? IP

45. © 2004Kizoom 45 DATEX II Data Content Exchange Behaviour Transport Protocol defined XML schema (draft, work in progress) D2 deliverable specifies… may be revised? in progress for 2006 publication HTTP GET, POST, SOAP.

46. © 2004Kizoom 46 Some Conclusions TransModel invaluable –Vocabulary & concepts –Tool for harmonisation legacy standards Message architectures critical for real time efficiency –Based on proven architectures Modularity for legacy migration –Incremental implementations, optional features –XML allows flexible coupling –Road map for additional features

47. © 2004Kizoom 47 SIRI Further Technical Points

48. © 2004Kizoom 48 SIRI XSD Packages – Layered Reuse Common Request Management Common Request Management SIRI Functional Services Low Level Types SIRI Common Model

49. © 2004Kizoom 49 Recovery & Restart Subscriber is responsible for recreating subscriptions on restart, Consumer is responsible for Detecting Loss –Check Status –Heartbeat Consumer must know Subscriber!

50. © 2004Kizoom 50 Subscription Management Roles “Stateful pattern of interaction” –Subscriber assigns identifier –Notification Producer grants new subscriptions –Subscription manager handles any changes Notification Producer & Manager know each other Management Messages –SubscriptionRequest SubscriptionIdentifier –SubscriptionResponse Granted or refused –TerminateSubscriptionRequest

51. © 2004Kizoom 51 Extensions Access Control –Well defined Capabilities –Request based Checking Discovery –Capability –Coverage Stops Lines Product, Service, Vehicle - Features /Attributes ?

52. © 2004Kizoom 52 Access Controls Optional Capability on Requests –By ParticipantCode Configuration Matrix Restrict By –By Function &/or Capability (Static) E.g. Stop Events, Vehicle Movements –E.g. Subscribe, detail level –By Topic (Dynamic) E.g. Certain Stops, Certain Lines –By Resource level (Dynamic)

53. © 2004Kizoom 53 Appendix

54. © 2004Kizoom 54 Technical Challenges How to give migration path from existing standards –VDV, RTIG, TRIDENT –Allow alternative delivery patterns –Allow alternative formats for some detailed response messages where necessary. Semantically identical. –Allow modular, incremental implementation: roadmap What is canonical TransModel XML? –Trident XML not being kept current Further improvements in TransModel since Trident New developments/standards in XML / WS technology Further application requirements for SIRI What real-time efficiency optimisations are needed? –Principle of strict Transmodel Isomorphism ? –Allow different message patterns and tradeoffs

55. © 2004Kizoom 55 Acceptable Optimisations =TransModel Isomorphic? A B F C D * * Bs Cs E G * 11 A X (C+D+E) * Cs G 1 1 1 1 * A B C D * * Bs Cs E G * 1 1 1 1 OK NOT OK Compression Compounding *

56. © 2004Kizoom 56 SIRI Data Models TransModel based; Small Subset Common Concepts& Elements –Participants (Systems) –StopPoints (Pluggable to national systems) –Lines, Directions –Journeys, VehicleJourneys & Calls DatedVehicleJourneys & Calls MonitoredVehcielJourneys & Calls ConnectingJourneys –Features Service Vehicle Product Common Structures –Isomorphic optimisations of TransModel for use in interface

57. © 2004Kizoom 57 Example Stop Monitoring Request NADER 2004-12-17T09:30:47-05:00 2004-12-17T09:30:47-05:00 P30M EH00001 7 2 normal

58. © 2004Kizoom 58 Example Stop Monitoring Delivery 2004-12-17T09:30:47-05:00 NADER 2004-12-17T09:30:47-05:00 2004-12-17T09:25:46-05:00 HLTST011 Line123 Out 2004-12-17 034567 123 Paradise Park VEH987654 0014 false 2004-12-17T09:40:44-05:00 2004-12-17T09:40:46-05:00 2004-12-17T09:42:47-05:00 2004-12-17T09:40:47-05:00 ……..