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 v3.6b

2. © 2004Kizoom 2 Topics General Background Transport & Communications Specific Functional Services Review Process and Completion

3. © 2004Kizoom 3 General Background & Overview

4. © 2004Kizoom 4 SIRI - CEN TC278 WG3 SG7 Real-time Server-to-Server Services for PTVs –Based on: TransModel : Terminology, model (isomorphic) XML, WS-PubSub  Web Service enabled VDV 453,454, Trident, RTIG – Real systems & experience! –Useful for Specifying & Implementing AVMS, PTI and UTMC systems –European economies of scale Participants –Germany (VDV453, VDV 454) –France (Trident, TransModel) –UK (RTIG-XML, TransModel) –Denmark, Sweden, Norway, (PubTrans) Deliverables (April 2005) –Technical Standard Document (for consultation) –Supporting XML Schema – W3C.XSD –Support WSDL /SOAP binding using same xsd schema Migration path from existing standards

5. © 2004Kizoom 5 Gene Pool

6. © 2004Kizoom 6 Motivation - Uses Of SIRI Services Rapid growth in real-time info - makes PT more efficient & 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.

7. © 2004Kizoom 7 Motivation - Standards Value to PTEs / Customers –Open 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 –Lowers costs - creating new markets –Modern, Modular, scaleable architectures –Harnesses open internet standards

8. © 2004Kizoom 8 Support Different Operation Models Interface s can be used for different operational models

9. © 2004Kizoom 9 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 Able to optimise for different operational characteristics

10. © 2004Kizoom 10 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

11. © 2004Kizoom 11 SIRI Approach & Services Separation of Concerns –Transport layer is separate (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

12. © 2004Kizoom 12 SIRI is an XML Dynamic Protocol What to Exchange? –Message Payload Structure Content model Requests, responses, Derived from TransModel + National systems –Data reference systems Stop identifiers, Lines, times etc How to Exchange it? – Protocols & message patterns –Transport –Mediation Derived from existing National systems

13. © 2004Kizoom 13 Transport & General Communications

14. © 2004Kizoom 14 General Communications Services #1 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

15. © 2004Kizoom 15 SIRI Communications Layer Common to all Functional Services

16. © 2004Kizoom 16 General Communications Services #1 General Functions Common to all SIRI Service Types –Subscription Management –Recovery & Restart –Access Controls –Versioning –Discovery Some Capabilities are Optional

17. © 2004Kizoom 17 General Communications Services #2 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

18. © 2004Kizoom 18 Interaction 1- Request/Response

19. © 2004Kizoom 19 Interaction 2- Publish/Subscribe

20. © 2004Kizoom 20 Publish Subscribe -WS-PubSub New Coherent Family of web service standards for stateful patterns of interaction. IBM, Microsoft, Tipco, Akamai, Sonic –State WS-Address W3C WS-BaseFaults WS-Resource WS-Topics WS-ServiceGroup –Stateful Resource Patterns WS-Resource Lifetime WS-BaseNotification WS-BrokeredNotification WS-PubSub SIRI aims to be WS-PubSub enabled –Similar concepts, terminology and separation of concerns –SIRI V1 does not attempt a SOAP WSDL encoding / binding

21. © 2004Kizoom 21 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

22. © 2004Kizoom 22 Delivery - Direct & Fetched

23. © 2004Kizoom 23 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

24. © 2004Kizoom 24 Mediation Interaction of simple patterns can be quite complex.

25. © 2004Kizoom 25 Use of Interaction Patterns MediationDirect Delivery Fetched Delivery Request / Response --RtigXml, Trident -- Publish / Subscribe Last UpdateRtigXml, Trident VDV453 Change Threshold Subscription Aggregation --

26. © 2004Kizoom 26 SIRI Functional Services

27. © 2004Kizoom 27 PT Systems & SIRI Interfaces aa Generic model of PT operations, showing exchange points for RTI

28. © 2004Kizoom 28 SIRI Timetable Servcies Production Timetable –Distribute latest timetable Schedule to AVMS AVMS to client Estimated Timeable –Distribute latest timetable including real-time Cancellations, additions, short working Realtime-predictions

29. © 2004Kizoom 29 SIRI Stop Services Stop Timetable –Distribute latest timetable Stop Centric Timetable Provisions Clients. Stop Monitoring –Real time Arrival & Departure Boards –Arrivals, Departures, passthroughs

30. © 2004Kizoom 30 SIRI Connection Services Connection Timetable –Distribute planned interchanges Stop Centric Provisions Clients. Connection Monitoring –Connection management –Guranteed connection support

31. © 2004Kizoom 31 SIRI General Message Services General Message –Exchange structured messages Simple or embedded structures

32. © 2004Kizoom 32 SIRI Further Technical Points

33. © 2004Kizoom 33 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

34. © 2004Kizoom 34 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 *

35. © 2004Kizoom 35 SIRI Functional Requests

36. © 2004Kizoom 36 SIRI Subscription Requests

37. © 2004Kizoom 37 SIRI Common Request Structure

38. © 2004Kizoom 38 Subscription Response

39. © 2004Kizoom 39 Response Status

40. © 2004Kizoom 40 Siri Deliv ery

41. © 2004Kizoom 41 Common Delivery Structure Example Delivery for Stop Monitoring

42. © 2004Kizoom 42 Recovery & Restart Subscriber is responsible for recreating subscriptions on restart, Consumer is responsible for Detecting Loss –Check Status –Heartbeat Consumer must know Subscriber!

43. © 2004Kizoom 43 Detecting a Loss of Service – Check Status

44. © 2004Kizoom 44 Detecting a Loss of Service - Heartbeat

45. © 2004Kizoom 45 Extensions Access Control –Well defined Capabilities –Request based Checking Discovery –Capability –Coverage Stops Lines Product, Service, Vehicle - Features /Attributes ?

46. © 2004Kizoom 46 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)

47. © 2004Kizoom 47 Discovery

48. © 2004Kizoom 48 Stop Points Delivery

49. © 2004Kizoom 49 Discovering Capabilities