Model-based cross-layer monitoring and adaptation of multilayer systems

Abstract

With the vision of “Internet as a computer”, complex software-intensive systems running on the Internet, or the “Internetwares”, can be also divided into multiple layers. Each layer has a different focus, implementation technique, and stakeholders. Monitoring and adaptation of such multilayer systems are challenging, because the mismatches and adaptations are interrelated across the layers. This interrelation makes it difficult to find out: 1) When a system change causes mismatches in one layer, how to identify all the cascaded mismatches on the other layers? 2) When an adaptation is performed at one layer, how to find out all the complementary adaptations required in other layers? This paper presents a model-based approach towards cross-layer monitoring and adaptation of multilayer systems. We provide standard meta-modelling languages for system experts to specify the concepts and constraints separately for each layer, as well as the relations among the concepts from different layers. Within each individual layer, we use run-time models to represent the system state specific to this layer, monitor the systems by evaluating model changes according to specified constraints, and support manual or semi-automated adaption by modifying the models. When a change happens in the run-time model for one layer, either caused by system changes or by the adaptation, we synchronize the models for other layers to identify cascaded mismatches and complementary adaptations across the layers. We illustrate the approach on a simulated crisis management system, and are using it on a number of ongoing projects.