Contracts for defining QOS levels in a Multichannel Adaptive Information System

1. Contracts for defining QOS levels in a Multichannel Adaptive Information System Moreno Callea, Luca Campagna Mariagrazia Fugini, Pierluigi Plebani Dip. Elettronica ed Informazione Politecnico di Milano – Italy MOBIS 2004 Conference - September 15th, 2004 - Oslo, Norway

2. Outline • Multichannel adaptive information systems • Quality of service model • WSLA extensions • Prototype • Concluding remarks MOBIS 2004 - Oslo, Norway

3. Service Oriented Architecture ServiceDirectory (broker) publish find Transmission medium invoke ServiceRequestor ServiceProvider MOBIS 2004 - Oslo, Norway

4. Multichannel Information Systems • Today the services are usually provided by a single-channel (Web) • We want to provide services through different channels: • Smartphone • PDA • … MOBIS 2004 - Oslo, Norway

5. Multichannel adaptive Information Systems • The client • could change the channel, during service exploitation • The system • could adapt the service provisioning by changing the provisioning channel • according to quality of service (QoS) parameters MOBIS 2004 - Oslo, Norway

6. MAIS Project • Italian research project • Aims at studying a set of models and methodologies which allow service provisioning through different channels • Web Site: http://www.mais-project.it MOBIS 2004 - Oslo, Norway

7. Quality of Service • adaptation strategies • both the service and provider side • depend on the QoS definition • channel • deeply affects the values of the QoS parameters on the provider side • so the user can perceive different values according to the active channel • In a service oriented environment we have to consider all the involved actorsindependently MOBIS 2004 - Oslo, Norway

8. Our model • Composed by: • A system model: objects and actors • A set of roles and rules • association of quality information to objects • relationships among them • Quality information expressed by: • Quality parameters • Quality sets MOBIS 2004 - Oslo, Norway

9. Quality Model MOBIS 2004 - Oslo, Norway

10. Quality of Experience • Represents the quality perceived by the user • Composed by the same quality parameters belonging to the QoS where the values are affected by the QoN, and QoD QoN QoD Quality rules QoE <framerate, [5fps..20fps]> <colordepth, [2bit..16 bit]> <resolution, [800×600]> QoS <framerate, [5fps..30fps]> <colordepth, [2bit..24 bit]> <resolution, [320×200; 800×600]> MOBIS 2004 - Oslo, Norway

11. Contracts • Service provider and service user must agree on the quality parameters • Contract is in charge to define this agreement defining: • Roles • Quality parameters • Responsibilities MOBIS 2004 - Oslo, Norway

12. Main existing specifications • QML (Quality of Service Modeling Language) • uses an OOP approach to define the QoS parameters • XQOS (XML Based QoS Specification Language) • Xml-based, • Related to multimedia systems • Define relationship between users and provider through the channel • WSLA (Web Service Level Agreement) • Xml-based, • Close related to the Web Service environment MOBIS 2004 - Oslo, Norway

13. WSLA MOBIS 2004 - Oslo, Norway

14. WSLA extensions • New attributes to specify the <network, device> pairs • Concept defined in QML is adopted • Ordering • Data Type: Numeric, Set, Enum MOBIS 2004 - Oslo, Norway

15. Guarantee terms • Service Level Objective: • For each <network, device> • Attributes: Name, Device, Network interface, Order • Data timeliness • Admissible range for each quality parameters • Action Guarantee: • Action performed in case of unfulfillment • Who violates MOBIS 2004 - Oslo, Norway

16. Prototype architecture MOBIS 2004 - Oslo, Norway

17. Prototype architecture MOBIS 2004 - Oslo, Norway

18. Conclusions • This work presents a framework to define the quality information in a multichannel information system • It is based on a model where all the involved actors can separately state the quality information for the controlled object • A monitoring system is required MOBIS 2004 - Oslo, Norway