MinHop (MH) Transmission strategy to optimized performance of epidemic routing protocol

Delay tolerant network aims to provide the network architecture in environments where end-to-end path may never exist for long duration of time Furthermore dynamic topology changes limited buffer space and non stable connectivity make routing a challenging issue The research contribution regarding DTN routing protocols can be categorized in to single and multi copy strategies A single copy strategy makes less use of network resources but suffers from long delay and less delivery probability Multi copy schemes enjoy better delivery probability and minimum delivery delay at the cost of heavy use of network resource Moreover DTN nodes operate under short contact duration and limited transmission bandwidth Therefore it is not possible for a node to transmit all messages from its forwarding queue Hence the order at which the messages are forwarded becomes very vital In this paper we propose a forwarding queue mode named MinHop We prove through simulations that the proposed policy performs better then FIFO in terms of delivery probability overhead message drop and rela

Mean drop an effectual buffer management policy for delay tolerant network

Traditional routing protocols e.g. TCP/IP, AODV cannot be configured in environments where end-to-end path is not stable due to network partitioned, dynamic topology changes and node mobility. Delay tolerant Network (DTN) has emerged as a technology by which the communication architecture is formed through intermittently connected mobile nodes. These networks are categorized as opportunistic since further availability of connections cannot be predicted. Thus, the routing protocols transmit the multiple copies of each message around the connected nodes. Each node then carries this message copy in its buffer until the transmission opportunity arises. This hop-by-hop mobility of message(s) makes the quick progress towards destination. However, such redundant diffusion of messages produces high congestion in the network and a situation occurs where new message arrives at a node and its buffer is full. In this case, the node must drop the buffered message(s) to sustain this new arrival. The function of buffer management policy is to minimize this drop. In this paper we propose a buffer management policy called as MeanDrop. This policy computes the mean of buffered messages at the congested node and drops only those message(s) which have the size greater than or equal to this mean value. The simulation results have shown that the proposed policy MeanDrop (MD) out performs well as compared to existing Evict Shortest Time First (ESTF) and Evict Most Forwarded Fist (MOFO) in terms of message relay, message drop, delivery probability and overhead

The optimization of spray and wait routing protocol by prioritizing the message forwarding order

In most of the wireless applications, e.g. military networks, vehicular ad-hoc networks, wild life tracking and sensor network, it is impossible to sustain a complete end-to-end data transmission path from source to destination. Thus, the traditional routing strategies (TCP/IP) cannot work with such environments as they need to establish the uninterrupted path before transmission. The disruption-tolerant network (DTNs) has emerged as technology that enables the communication in highly disrupted environments by intermittently connected mobile nodes. The DTN transmission model follows a store carry and forward mechanism wherein the nodes stores the incoming message , carries it while moving and forward when comes in the transmission range of other contacts. The DTN protocol can be divided as single copy and multi copy. In single copy protocol the node is allowed to generate the unique copy of message and forward it on a unique path. The multi copy protocols generate and transmit the multiple copies of each message and forward it along various paths. In DTN environment, the communication opportunity exists for short duration and a node cannot transmit all copies of its carried message from its forwarding queue. Hence the order at which the messages are forwarded becomes very important. In this paper, we have proposed a message forwarding order for multi copy Spary&wait routing protocol called as smallest message first. Through simulations, we proved that proposed policy out perform as compared to existing FIFO in context of delivery probability, overhead, latency average and buffer time average

Investigating severity of blackhole attack and its variance in wireless mobile ad hoc networks

Blackhole attack is a common attack in mobile ad hoc network (MANET). Generation of this attack is simple, which does not require special tools or sophisticated attack techniques. Various solutions to prevent this attack have been proposed. However, none of them has measured the severity of this attack. In fact, the assessment of severity is essential to develop effective and efficient prevention against the attack. The purpose of this study is to investigate the severity of blackhole attack. In this investigation, new security metrics, namely corruption routing table (CRT), compromising relay node (CRN) and compromising originator node (CON), have been proposed and used for the severity evaluation. In addition, a new blackhole attack, namely hybrid blackhole attack (HBHA) with two variants - independent and cooperative HBHAs are also introduced for the purpose of comparative study. Simulations using Java in time simulator/scalable wireless ad hoc network simulator (JiST/SWANS) show that the proposed metrics are effective in assessing the severity of the blackhole attacks. Among these three blackhole attacks, independent HBHA is the most severe attack. Meanwhile, the cooperative HBHA is the most efficient attac