Project full title : Highly dependable ip - based networks and services

Resilient topologies and routing are among the important topics that were addressed within the HIDENETS project and have been the focus of task 1 of Work Package 3 ‘Resilient Communication’. This document provides the results of the work in this area. The document has the following content: (1) The HIDENETS network architecture is described, introducing the relevant terminology and the use cases that are of specific interest for this task. (2) The HIDENETS node software architecture is described. This architecture is developed jointly within the Work Packages 2 and 3. The focus here is on the blocks that have specific relevance for resilient topologies and routing and that has been handled within this task. (3) Resilience is about managing failures and implementing mechanisms that make the system resilient and robust despite possible occurrences of failures. We have therefore analyzed possible faults, errors and failures, and their consequences with respect to the HIDENETS scenarios. The result of this fault analysis is presented. The focus has been on timing faults and value faults and the causes of such faults. We classify the faults that are most relevant for the communication layer and give the motivation for addressing these faults by developing the methods further described in this deliverable (see below). This is done with emphasis on the methods ability to enhance the resilience and dependability of the network. (4) Finally these more specific research topics that have been addressed in this task by extensive theoretical studies are described and the results are presented. This is divided into the areas ‘multi-channel multi-radio architecture’, ‘resilience in stand-alone ad-hoc networks’ and ‘resilience in accessing infrastructure networks’. Using multiple frequency channels improves communication level properties, especially capacity. Using multiple radios per node also allows for using multiple channels without any synchronisation between nodes. Multiple radios can also be used for increased redundancy both in ad-hoc networks and in access to infrastructure (multihoming). Resilience in stand-alone ad-hoc networks aims at making the network more resilient by increasing the redundancy and decreasing the signalling / broadcasting overhead. This will improve the connectivity and reduce the probability of contention. Resilience in accessing the infrastructure aims at increasing the redundancy using multihoming and simultaneously protecting mobile terminals that have the highest dependability requirements in cases of failures in this part of the network. Keyword list: resilience, ad-hoc network, routing, multi-channel, multi-radio, multi-homing, multitopology, multi-path.