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Recent work on geographic routing protocols has shown that Global Navigation Satellite System (GNSS) Position Navigation and Timing (PNT) positional error directly affects message delivery rates (MDRs) within Delay and Disruption Tolerant Networks (DTNs). Although research within this area continues, optimization techniques and the potential facilitation of new protocols that are immune or are relatively impervious to PNT positional error have not been thoroughly explored, nor has their application been studied within the Department of Defense (DOD). Accuracy within DTNs, especially in urban and natural canyons, that is complementary with higher MDRs is a desirable characteristic for the warfighter operating in challenging environments. This thesis examines four geographic routing protocols, specifically looking at their current state, potential optimizations, and performance after artificially introducing PNT position error. Analysis of the results showed that certain geographic routing protocol performance metrics are drastically degraded when positional error is introduced, whereas others remain unaffected or were improved. Specifically, we observed a surprising result for certain protocols where performance was improved when PNT positional error was introduced., Lieutenant Commander, United States Navy, Approved for public release. distribution is unlimited

A Disruption Tolerant Network (DTN) is a sparse network where connectivity is regulated by the proximity of mobile nodes. Connections are sporadic and the delivery rate is closely related to node movement. As network resources often are limited in such settings, it is useful to monitor the network in order to make more efficient communication decisions. This study investigates existing routing protocols and monitoring tools for DTN that best cope with the requirements of a tactical military network. A model is proposed to estimate source to destination delay in DTN. This model is evaluated in a Java-based software simulator called The ONE. In order to match the tactical military environment, two scenarios are constructed. The squad scenario simulates the formation movement pattern of several squads and the hierarchical communication scheme that is maintained in a military context. The other scenario simulates a convoy line movement of a military group during transportation. The results of this study show that the proposed mechanism can improve delivery rate and reduce network overhead in settings with strict buffer limitations. The estimation worked best in scenarios that contained some patterns of movement or communication. These patterns are resembled in the model's collected data and the model can provide the user with rough estimates of end-to-end delays in the network. Primary use of this model has been to reduce number of old messages in the network, but other applications like anomaly detection are also discussed in this work., Ett avbrottstolerant nätverk (DTN) är ett glest nät där konnektiviteten avgörs av närheten bland de rörliga noderna i nätverket. Avbrotten i ett sådant nät förekommer ofta och sporadiskt. Eftersom nätverksresurserna oftast är begränsade i sådana sammanhang, så är det lämpligt att övervaka nätverket för att göra det möjligt att fatta mer effektiva kommunikationsbeslut. Det här arbetet undersöker olika routingalgoritmer och övervakningsvektyg för DTN med hänsyn till de krav som ställs av ett taktiskt nät. En modell för att uppskatta fördröjningen från källa till destination är framtagen i arbetet. Modellen är utvärderad med hjälp av en Javabaserad mjukvarusimulator som heter The ONE. För att bäst representera den miljö som uppstår i militära sammanhang är två scenarion framtagna. Det första är ett truppscenario där nodernar rör sig i fromationer och nättrafiken följer den hierarkiska modellen som används i militär kommunikation. Det andra scenariot är ett konvojscenario där enheter marcherar på led. Resultaten från denna studie visar att den föreslagna modellen kan öka andelen levererade meddelanden och minska nätverksbelastningen i en miljö där bufferstorleken hos noderna är begränsad. Uppskattningen visade sig fungera bäst i scenarion som innehöll någon form av mönster bland nodernas rörelse eller deras kommunikation. Dessa mönster återspeglas i modellens insamlade data och modellen kan förse användaren med en grov estimering av slutfördröjningen till alla destinationer i nätet. Modellen har i huvudsak använts till att minska antalet gamla meddelanden i nätet, men arbetet berör även andra användningsområden som anomalidetektion.

This thesis explores the foundation of modern Disruption Tolerant Protocols. It introduces a previously unpublished protocol with high probability of delivery called the Geolocation Assisted Predictive Routing (GAPR) Protocol and implements Vector Routing for The ONE Simulator. GAPR and Vector are then combined and implemented as GAPR2, a new protocol that provides delivery ratio near the best in the field while incurring a quarter of the overhead. GAPR2, GAPR, and Vector, along with the most widely referenced DTN routing protocols (Epidemic, MaxProp, and PRoPHETv2) are extensively simulated and their performance evaluated using three mobility models: the Helsinki scenario, a random mobility model, and a military scenario based on a real-world annual exercise. The custom-built military mobility model uses GIS topographical data and custom GIS overlays to implement a realistic scenario terrain. The performance of each protocol is evaluated. This thesis shows through simulation that DTN networks can be employed to enhance communications capabilities without expensive infrastructure or significant platform upgrades. Further, this thesis shows through large-scale simulations that such a network is capable of operating over hundreds of square kilometers and provides the simulation framework to test future routing protocols or equipment configurations., http://archive.org/details/gaprdtnroutingpr1094547288, Lieutenant, United Stated Navy, Approved for public release; distribution is unlimited.

This thesis studies the performance of Disruption Tolerant Networking (DTN) routing protocols, and the effect of simulator selection. Research into the Geo-location Assisted Predictive Routing (GAPR), and GAPR2 protocols at NPS used the ONE Simulator. The ONE abstracts everything below the routing layer to simplify the development of DTN protocols. In contrast, Network Simulator 3 (ns-3) simulates the entire network stack. ns-3 includes packet headers and existing link-layer protocols that the ONE abstracts away. The inclusion of link-layer overhead and packet headers reduces message delivery by 31% and increases average latency by 119%. Packets used to share routing information consume up to 33% of all transmitted data. Effective throughput between connected nodes decreases by 40%-70% of the equivalent ONE bandwidth. These penalties vary significantly depending on routing protocol design choices. This thesis implements Epidemic, Vector, Centroid, GAPR, and GAPR2 protocols in ns-3. It also combines Centroid with GAPR to create a new protocol called GAPR2a. The protocols are extensively simulated in three mobility scenarios in ns-3 and the ONE: one urban scenario and two military scenarios. GAPR2a provides the best overall performance in the urban scenario, and Vector provides the best overall performance in the military scenarios. Future DTN protocol development should continue in ns-3 because the ONE's abstractions may not reflect real-world performance., http://archive.org/details/comparativenalys1094556763, Outstanding Thesis, Lieutenant, United States Navy, Approved for public release; distribution is unlimited.