Implementation of Epidemic Routing with IP Convergence Layer in ns-3

We present the Epidemic routing protocol implementation in ns-3. It is a full-featured DTN protocol in that it supports the message abstraction and store-and-haul behavior. We compare the performance of our Epidemic routing ns-3 implementation with the existing implementation of Epidemic in the ONE simulator, and discuss the differences

FALCON: A New Approach for the Evaluation of Opportunistic Networks

[EN] Evaluating the performance of opportunistic networks with a high number of nodes is a challenging problem. Analytical models cannot provide a realistic evaluation of these networks, and simulations can be very time-consuming, sometimes requiring even weeks only to provide the results of a single scenario. In this paper, we present a fast evaluation model called FALCON (Fast Analysis, using a Lattice Cell model, of Opportunistic Networks) that is computationally very efficient and precise. The model is based on discretising space and time in order to reduce the computation complexity, and we formalised it as a discrete dynamic system that can be quickly solved. We describe some validation experiments showing that the precision of the obtained results is equivalent to the ones obtained with standard simulation approaches. The experiments also show that computation time is reduced by two orders of magnitude (from hours to seconds), allowing for a faster evaluation of opportunistic networks. Finally, we show that the FALCON model is easy to adapt and expand to consider different scenarios and protocols.This work was partially supported by Ministerio de Economia y Competitividad, Spain, grant TEC2014-52690-R.Hernández-Orallo, E.; Cano, J.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2018). FALCON: A New Approach for the Evaluation of Opportunistic Networks. Ad Hoc Networks. 81:109-121. https://doi.org/10.1016/j.adhoc.2018.07.004S1091218

Network Resilience Improvement and Evaluation Using Link Additions

Computer networks are getting more involved in providing services for most of our daily life activities related to education, business, health care, social life, and government. Publicly available computer networks are prone to targeted attacks and natural disasters that could disrupt normal operation and services. Building highly resilient networks is an important aspect of their design and implementation. For existing networks, resilience against such challenges can be improved by adding more links. In fact, adding links to form a full mesh yields the most resilient network but it incurs an unfeasibly high cost. In this research, we investigate the resilience improvement of real-world networks via adding a cost-efficient set of links. Adding a set of links to an obtain optimal solution using an exhaustive search is impracticable for large networks. Using a greedy algorithm, a feasible solution is obtained by adding a set of links to improve network connectivity by increasing a graph robustness metric such as algebraic connectivity or total graph diversity. We use a graph metric called flow robustness as a measure for network resilience. To evaluate the improved networks, we apply three centrality-based attacks and study their resilience. The flow robustness results of the attacks show that the improved networks are more resilient than the non-improved networks

Future Internet Routing Design for Massive Failures and Attacks

Given the high complexity and increasing traffic load of the Internet, geo-correlated challenges caused by large-scale disasters or malicious attacks pose a significant threat to dependable network communications. To understand its characteristics, we propose a critical-region identification mechanism and incorporate its result into a new graph resilience metric, compensated Total Geographical Graph Diversity. Our metric is capable of characterizing and differentiating resiliency levels for different physical topologies. We further analyze the mechanisms attackers could exploit to maximize the damage and demonstrate the effectiveness of a network restoration plan. Based on the geodiversity in topologies, we present the path geodiverse problem and two heuristics to solve it more efficiently compared to the optimal algorithm. We propose the flow geodiverse problem and two optimization formulations to study the tradeoff among cost, end-to-end delay, and path skew with multipath forwarding. We further integrate the solution to above models into our cross-layer resilient protocol stack, ResTP–GeoDivRP. Our protocol stack is prototyped and implemented in the network simulator ns-3 and emulated in our KanREN testbed. By providing multiple GeoPaths, our protocol stack provides better path restoration performance than Multipath TCP

Resilience Evaluation and Enhancement in Mobile Ad Hoc Networks

Understanding network behavior that undergoes challenges is essential to constructing a resilient and survivable network. Due to the mobility and wireless channel properties, it is more difficult to model and analyze mobile ad hoc networks under various challenges. We provide a comprehensive model to assess the vulnerability of mobile ad hoc networks in face of malicious attacks. We analyze comprehensive graph-theoretical properties and network performance of the dynamic networks under attacks against the critical nodes using both synthetic and real-world mobility traces. Motivated by Minimum Spanning Tree and small-world networks, we propose a network enhancement strategy by adding long-range links. We compare the performance of different enhancement strategies by evaluating a list of robustness measures. Our study provides insights into the design and construction of resilient and survivable mobile ad hoc networks

Modelagem matemática do atraso de entrega de mensagens em redes oportunistas com taxas de encontro heterogêneas

Presents the development of two mathematical models to capture the expected end-to-end message delivery delay in opportunistic networks, for singlecopy and multi-copy forwarding process, when the source node can generate multiple copies of the message. The research area of opportunistic networks is becoming stronger over the years. However, despite of the diversity of protocols and solutions proposed for dealing with the challenges of this environment, there is an open issue in the literature that is the lack of general mathematical models. This gap is the major motivation for the present work. The mathematical modeling proposed in this document focus on the dynamics of encounters among nodes, taking into consideration the heterogeneity in their mobility, which assumes that the pairwise encounter rates are different. The first model was inspired by a single-copy model of the literature and expanded to the multi-copy case. The second model, which considers both single and multi-copy cases, follows a different approach and was developed to eliminate some approximations used in the first model. Both models were validated by comparing analytical and simulation results. Three simulation tools were used: a proper simulator specially developed for this work and the network simulators ns-3 and The ONE. The obtained results show the high precision of the estimates, for both synthetic and real life traces.Apresenta o desenvolvimento de dois modelos matemáticos para predição do atraso de entrega de mensagens fim-a-fim em redes oportunistas, para processos de encaminhamento single-copy e multi-copy, quando o nó origem pode criar múltiplas cópias da mensagem. A área de pesquisa em redes oportunistas vem crescendo ao longo dos anos, mas, apesar da diversidade de propostas de protocolos e soluções para os desafios desse ambiente, existe um problema em aberto na literatura que é a carência de modelos matemáticos. Essa lacuna é a principal motivação do presente trabalho. O foco principal desta modelagem é a dinâmica de encontros entre os nós, levando em consideração a heterogeneidade na mobilidade dos mesmos, que pressupõe que as taxas de encontro de cada par de nós são diferentes. O primeiro modelo proposto foi inspirado em um modelo single-copy da literatura e expandido para o caso multi-copy. O segundo modelo, que engloba ambos os casos single-copy e multi-copy, segue uma abordagem diferente e foi desenvolvido com a finalidade de eliminar aproximações usadas no primeiro. Os modelos foram validados por meio da comparação dos resultados analíticos com resultados de simulação. Três ferramentas de simulação foram utilizadas: um simulador próprio especialmente desenvolvido para este trabalho e os simuladores de redes ns-3 e The ONE. Os resultados obtidos mostram uma alta precisão da modelagem, tanto para traces sintéticos quanto para traces reais