On improving usability and network management of challenging systems

The modern Internet is built on top of Internet Protocol (IP) and is based on the assumption of end-to-end connectivity, low packet loss, and low delay. However, also other kinds of network exist and they are common, e.g., in rescue and resiliency operations and in the military context. In these networks, the messaging is done over intermittently connected and heterogeneous network media using concepts of Delay/Disruption Tolerant Networking (DTN). Further, in these challenging network systems the operators are typically part of a strongly hierarchical organization structure, and the context of use is highly user-centric. This thesis focuses on improving the usability and network management of challenging network systems. In challenging systems, intermittent network connectivity and heterogeneity of underlying network media set challenges to both usability and management of the systems. Further, the harsh operation environment, users with different skills and computer literacy, and variation in terminal devices set additional challenges to the usability. The thesis presents technical solutions and UI design principles that can be used to improve the usability of challenging systems, and shows how the usability of challenging systems can be evaluated. Results of two usability evaluations are presented and analyzed, and suggestions based on the findings are given. Further, the thesis introduces a way to access and manage heterogeneous network interfaces of a system, and presents a related generalized solution that can be used to configure any heterogeneous system component. On the system level, the thesis shows how a network of a hierarchically structured organization that operates in a DTN environment can be managed using hierarchy-based methods. The thesis presents the impact of the hierarchy to network management centralization, network quality in different parts of the network, roles and responsibilities of the managing and managed nodes, and configurability and messaging between the nodes. A comparison to an equivalent non-hierarchical solution shows that hierarchical management requires proportionally more preconfiguration but improves performance significantly.