Network Structure Modelling and Traffic Simulation with CO-OPN David Hürzeler SMV Group, Geneva University 5/7/2005

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

The problem Using Petri nets and formal methods for accident modelling and risk analysis. Using Petri nets and formal methods for accident modelling and risk analysis. Focus on network problems which raise many interesting issues (performance, fault-tolerance, mobility, error propagation, probabilities, etc…) and the results on which can be translated to other risk domains. Focus on network problems which raise many interesting issues (performance, fault-tolerance, mobility, error propagation, probabilities, etc…) and the results on which can be translated to other risk domains.

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

The network example Router C Router BRouter A Router E Router DRouter F

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

First CO-OPN model

The network context r1.sendMess m from id to idd via id2 With r2.routerId id2.. r2.receiveMess m from id to idd; Router r1 (id1) routerId _ receiveMess _ from _ to _ sendMess _ from _to _ via _ Router r2 (id2) routerId _ receiveReqMess _ from _ to _ sendMess _ from _to _ via _..

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

Router with Queues Router r1 Routing Table Queue Receive Send Routing Table Queue Receive Send Router r2

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

Simulation In fact, the above model is wrong : the « proceedAllrequests » method of the Network context is never firable.

Plan Introducing the problem Introducing the problem The network example The network example A first simple model A first simple model Adding queues to routers Adding queues to routers Detecting model flaws through simulation Detecting model flaws through simulation Future work: extensions and verification. Future work: extensions and verification.

Extensions Bigger systems (more routers, hierarchy of networks), Bigger systems (more routers, hierarchy of networks), Dynamic routing, message lotss, and fault olerance, Dynamic routing, message lotss, and fault olerance, Time, Time, Probabilities, Probabilities, Complex messages. Complex messages.

Verification CoopnBuilder Prototype tool CoopnBuilder Prototype tool GreatSPN GreatSPN SPIN (?) SPIN (?)