Networks & disputes

Networked systems often consist of inter-dependent subsystems that are governed by locally determined heterogeneous preferences or policies. Examples include interdomain routing, peer-to-peer storage, and decentralised security systems. This dissertation introduces a notion called dispute — a cyclic structure that underlies the dependence and preferences of subsystems. Disputes may cause adverse consequences to networked systems, such as oscillations (where a networked system fails to settle down at a system-wide consistent configuration) and non-determinism (where a networked system may exhibit unpredictable behaviour). In this dissertation: (1) Several interesting paradoxes in networking are presented, highlighting the ubiquity of disputes in networked systems. (2) The structures and consequences of disputes are studied in the framework of non-cooperative games, taking into account the characteristics of networks. (3) Complementary to the game-theoretical study, an algebra of networked systems is formulated, which offers an efficient approach to avoid disputes. (4) For unavoidable disputes, a distributed probabilistic mechanism for ad hoc dispute resolution is proposed and its performance is analysed with respect to various network topologies. The contribution of these results is to shed light on the theoretical foundations and principles of robust networked systems in a general framework.