A General and Specific Utility-Based Adaptive Routing for Delay Tolerant Networks

The nonexistence of an end-to-end path poses great challenges in directly adapting the traditional routing algorithms for ad hoc or mobile ad hoc networks (MANETs) to delay tolerant networks (DTNs). In this paper, an adaptive routing protocol that makes use of both self-aware and destination-aware utility metrics to evaluate the potential throughput between every pair of nodes is proposed. We theoretically analyze the nodes’ spraying process and discover the relationship between the initial number of copies and the latency of the message distribution process, by which we can further control the expected latency under a certain level. Compared with Epidemic, Spray And Wait Spray, And Focus and Encounter-based routing, our proposed algorithm is the only one that achieves comparable performance under both Helsinki City Scenario and Cambridge-iMote Scenario. 1. Introduction Delay/disruption tolerant networks are networks of self-organizing wireless nodes, where end-to-end connectivity is intermittent [1]. The communication model of the Internet is based on some inherent networking assumptions, for example, the existence of a continuous end-to-end path between two nodes, the relatively short round-trip delays, the symmetric data rates, and the low error rates [2]. However, in DTNs these assumptions usually fail, which leads to the fact that the TCP/IP protocol does not work [3]. Hence, many application protocols designed for the Internet architecture cannot operate well in the DTN scenarios such as InterPlanetary interNet (IPN) [4]. In [5], Khabbaz et al. pointed out that we need a new kind of network model when modeling existing and recently emerging wireless networks, especially those deployed in extreme environments (e.g., battlefields, volcanic regions, deep oceans, deep space, developing regions, etc.) where they suffer challenging conditions (e.g., military wars and conflicts, terrorist attacks, earthquakes, volcanic eruptions, floods, storms, hurricanes, severe electromagnetic interferences, congested usage, etc.) resulting in excessive delays, severe bandwidth restrictions, remarkable node mobility, frequent power outages, and recurring communication obstructions. Based on the observation that quite a few terrestrial networks exhibit delay-tolerant properties, albeit different nature: from sparse mobile ad hoc to sensor networks to mobile Internet access, it is found that delay tolerance exists as an important element to describe communication behavior and to design protocols suitable for operation in the corresponding challenged networking