Web Services Resilience Evaluation using LDS Load dependent Server Models

In the field of ICT, the term resilience is commonly used, understanding to mean the ability of a system to deliver acceptable service in the presence of faults. We interpret resilience assessment to mean assessment of ICT systems in evolving environments and conditions and in the presence of faults or failures of any kind. Resilience Measurement and benchmarking is an open problem, mainly referred to security-related problems. In this paper we propose to model Web Services (WS)as Load Dependent Servers (LDS), i.e. systems whose response time to a given request depends on the load at the time the request is received. Adoption of LDS-based models enable us to have a simple way to represent the System state. We propose to use this simple representation to quantify the system resilience comparing models built using off-line measurement and models built using on-line measurement.