Title of the Deliverable: Service Level Resilience Solutions for the Infrastructure Domain Version Information Table of Contents 3 Probabilistic Fault Detection Using Cross-layer Observations .............. 12 Contents of the Deliverable and Relation to Other Work Packages

The main objectives of WP2 are to define a resilient architecture and to develop a range of middleware solutions (i.e. algorithms, protocols, services) to address resilience requirements in the design of highly available, reliable and trustworthy distributed solutions. This deliverable presents research results concerning the development of middleware services within the HIDENETS environment, the objective of which is to facilitate the construction of resilient, dependable car2car applications operating in ad-hoc environments in cooperation with infrastructure based services. The deliverable complements the work presented in deliverable D2.3 (Service level resilience solutions for the ad-hoc domain), focusing on ideas that typically reflect improvements of the services presented in D2.3. These improvements can be achieved due to the possibility of operating over infrastructure environments, in addition to the exclusive operation over ad-hoc environments. The deliverable provides three contributions. Firstly, it addresses the problem of fault detection from the perspective of end-to-end services, which is addressed under a probabilistic scope and which is suitable for IP based communication systems in general. Then, it provides a study on the dependability/performance trade-off for replicated servers in the infrastructure domain. Finally, an extension to the Intrusion Tolerant Agreement service is introduced, which exploits the assumed availability of a reliable server in the infrastructure domain to improve the performance of the basic (non-extended) service, as presented in D2.3.