*communication Mechanisms for Message Delivery

Today’s Internet is characterized by heterogeneity, both at node– (e.g., smart phones, PDAs) and network level (e.g., wired/wireless infrastructure-based and ad-hoc networks, cellular-based networks). As the networks are becoming increasingly heterogeneous, it is expected that future internetworks will interconnect different types of network including wired, infrastructure-based wireless and infrastructureless wireless networks including multi-hop mobile ad-hoc networks (or MANETs). Additionally, a number of emerging applications such as environmental or habitat monitoring, emergency response, vehicular communication, to name a few, require that future internetworks be tolerant to frequent or long-lived connectivity disruptions. This connectivity disruption is the inherent property of Delay or Disruption Tolerant Networks (DTNs). Interconnecting these heterogeneous networks poses several challenges due to heterogeneity of nodes and networks. These challenges include seamless message delivery and identification of nodes especially when the nodes are mobile. We target these issues in this thesis. The contributions of this thesis are three fold. First, we present a classification of existing DTN routing protocols by breaking up existing routing strategies into tunable routing modules (forwarding, replication, coding). Then, we identify a set of useful design guidelines to show how and when a given routing module should be used, depending on the set of network characteristics exhibited by the wireless application. Second, we propose a new framework called MeDeHa to provide message delivery across heterogeneous networks prone to intermittent connectivity. MeDeHa is able to bridge infrastructurebased and infrastructure-less networks and makes them inter-operate seamlessly, through devices carrying multiple interfaces or part of several networks and by the integration of existing protocols (e.g., MANET protocols). We evaluate MeDeHa through extensive simulations using realistic synthetic and real mobility traces, and by performing hybrid experiments which run partly on simulator and partly on real machines. Third, we propose a naming mechanism called HeNNA for heterogeneous networks prone to connectivity disruptions which aims to provide message delivery to nodes irrespective of their current IP addresses. Henna can accommodate nodes equipped with multiple network interfaces and is compatible with the status-quo Internet routing. We also implement HeNNA within the MeDeHa framework and conduct experiments to showcase the operation of the complete message delivery and naming protocol suite.