Modelling the Next Generation ALICE Grid Middleware Using Coloured Petri Nets

JAliEn (Java ALICE Environment) is a new Grid middleware framework designed to satisfy the needs of the CERN ALICE Collaboration for the LHC Run 3. It aims to ameliorate past shortcomings of the original AliEn middleware, and to provide a high-performance, and high-scalability service to cope with the increased volumes of collected data. To achieve this, JAliEn comes with many significant architectural changes – something which is not without challenges in a distributed system. Not only are users unfamiliar with how the framework behaves and communicates, it could also potentially introduce system deadlocks. One possible way of describing and verifying distributed systems is through the use of Petri Nets (PNs), a modelling language designed for such purposes. Through an extension of it, known as Coloured Petri Nets (CPNs), unique “tokens” can be used to describe individual commands and actions as they are sent through the system. This allows to map, model, and possibly verify JAliEn and its architecture, which will be the focus of this contribution.