Recuperação e Monitoramento de Dados Utilizando a Rede de Transporte Público

Este artigo apresenta uma proposta de encaminhamento de mensagens testada com o modelo de mobilidade da Rede Integrada de Transporte Coletivo de Curitiba. A proposta inclui uma adaptação no protocolo Spray and Wait baseada na categorização dos veículos do transporte coletivo da cidade, priorizando a transmissão das mensagens para os ônibus que apresentam uma maior proximidade lógica com o destino. Em seguida, a proposta foi avaliada utilizando traços reais e um modelo de tráfego voltado para aplicações de monitoramento. Os resultados obtidos comprovam os ganhos da estratégia proposta, apresentando melhores taxas de entrega, menor atraso e menor sobrecarga quando comparados aos protocolos clássicos.

A comparative study on delay-tolerant network routing protocols

PurposeIn this study, we discuss three DTN routing protocols, these are epidemic, PRoPHET and spray and wait routing protocols. A special simulator will be used; that is opportunistic network environment (ONE) to create a network environment. Spray and wait has highest delivery rate and low latency in most of the cases. Hence, spray and wait have better performance than others. This analysis of the performance of DTN protocols helps the researcher to learn better of these protocols in the different environment.Design/methodology/approachDelay-Tolerant Network (DTN) is a network designed to operate effectively over extreme distances, such as those encountered in space communications or on an interplanetary scale. In such an environment, nodes are occasional communication and are available among hubs, and determinations of the next node communications are not confirmed. In such network environment, the packet can be transferred by searching current efficient route available for a particular node. Due to the uncertainty of packet transfer route, DTN is affected by a variety of factors such as packet size, communication cost, node activity, etc.FindingsSpray and wait have highest delivery rate and low latency in most of the cases. Hence, spray and wait have better performance than others.Originality/valueThe primary goal of the paper is to extend these works in an attempt to offer a better understanding of the behavior of different DTN routing protocols with delivery probability, latency and overhead ratio that depend on various amounts of network parameters such as buffer size, number of nodes, movement ratio, time to live, movement range, transmission range and message generation rate. In this study, we discuss three DTN routing protocols: these are epidemic, PRoPHET and spray and wait routing protocols. A special simulator will be used; that is opportunistic network environment (ONE) to create a network environment. Spray and wait have highest delivery rate and low latency in most of the cases. Hence, spray and wait have better performance than others. This analysis of the performance of DTN protocols helps the researcher to learn better of these protocols in the different environment.

Detecting Blackhole Attack using Encounter Records on Multi-Copy Routing Protocols in Delay Tolerant Networks (DTN)

Delay Tolerant Network (DTN) is a solution for intermittent connectivity and high delay. However, due to constrained connectivity, DTN is vulnerably susceptible to Blackhole attacks in which malicious nodes will drop all packets received from source nodes or relay nodes. The impact of a Blackhole attack can reduce the packet delivery ratio and waste resources from relay nodes that carry and forward messages. The encounter record scheme is one solution that can be applied to detect Blackhole attacks on the DTN. The encounter record mechanism is performed by utilizing a relay node that will store several records obtained from encounters between previous nodes, then the node will detect when a packet has dropped and a blacklist is performed on the node detected as a malicious node. Based on testing the performance of the routing protocol obtained that the encounter record scheme is able to detect malicious nodes so that it can again increase the delivery ratio and overhead ratio. The simulation results of this research showed that the Encounter Record has successfully detected Blackhole attacks with an average detection time of 1,5992 seconds in the spray-and-wait routing and 1,5342 seconds in the epidemic routing for 15 malicious nodes. Detection accuracy is 100% on spray-and-wait routing and 73,85% on routing epidemic for 15 malicious nodes.

ANALYSIS OF EPIDEMIC, PROPHET AND SPRAY AND WAIT ROUTING PROTOCOLS IN THE MOBILE OPPORTUNISTIC NETWORKS

Background: The opportunistic mobile networks (OMNs) are a type of mobile adhoc networks (MANETs) with delay-tolerant network (DTN) features, where the sender to receiver connectivity never exists most of the time, due to dynamic nature of the nodes and the network partition. The real use of OMNs is to provide connectivity in challenged environments. Methods: The paper presents the detailed analysis of three routing protocols, namely Epidemic, PROPHET and Spray and Wait, against variable size of the messages and the time to live (TTL) in the networks. The key contribution of the paper is to explore routing protocols with mobility models for the dissemination of data to the destination. Routing uses the store-carryforward mechanism for message transfer and network has to keep compromise between message delivery ratio and delivery delay. Results: The results are generated from the experiments with Opportunistic Network Environment (ONE) simulator. The performance is evaluated based on three metrics, the delivery ratio, overhead ratio and the average latency. The results show that the minimum message size (256 KB) offers better performance in the delivery than the larger message size (1 MB). It has also been observed that with the epidemic routing, since there are more message replicas, which in turn increase the cost of delivery, so with a smaller message, the protocol can reduce the overhead ratio with a high proportion. Conclusion: The average latency observed increases with the increase of the TTL of the message in three protocols with variation of the message size from 256KB to 1 MB.