Messages propagation control in Delay Tolerant Networks under epidemic routing protocol

The heterogeneous networks are those which can connect different devices running with different operating systems and using different protocols. The main problem with these networks is network connectivity. In order to ensure the continuous network connectivity between the nodes, the Delay Tolerant Networks (DTNs) are useful as they operate on extreme distances and depend up on the changing positions of the nodes. The Epidemic Routing Protocol (ERP) makes use of DTN concept. The previous works show the performance of Epidemic Routing Protocol in terms of packet delivery ratio, end-to-end delay, and energy consumption. In this work, the Epidemic Routing Protocol's performance for Delay Tolerant Networks will be evaluated by considering different parameters like, Average Latency, Energy Balancing Factor, and Number of Alive and Dead nodes.

Increasing the contact bandwidth in delay tolerant networks (DTNs) via multicopy routing leads to a decrease in data delivery delay and an improvement in throughput. In DTNs, in which nodes have both radio frequency (RF) and free space optical (FSO) PHY layers, contact bandwidth can be increased by using the FSO PHY as the data channel and performing multicasting. As we show in this paper, due to the highly directional nature of FSO, a naive broadcast strategy where the beam divergence includes all nodes in the broadcast set, it does not always result in the minimization of data delivery delay and the maximization of delivery probability. To this end, we develop multicast strategies for hybrid RF/FSO DTNs via an emulation of static conditions in mobile DTNs in which RF is primarily used for control. We show that the optimal multicast problem in static environments is an abstraction of the minimum weighted set cover problem, which is known to be NP-hard. To save on computation time, we propose a greedy local optimum heuristic. Performance of the various multicast techniques is comprehensively evaluated in a DTN simulator, using the Epidemic routing protocol. These evaluations show that our computationally cheap solution yields results identical to optimal while not compromising the performance of the DTN.

Research on vehicular ad hoc networks (VANETs) has focused primarily on efficient routing protocol design under conditions where there are relatively large numbers of closely spaced vehicles, typical of major highways and urban areas. These routing protocols are designed principally for fully connected networks and are not suitable for packet delivery in a sparse, partially connected VANET. In rural areas, vehicle densities are low and roadway communication infrastructure is scarce, leading to long periods where vehicle-to-vehicle or vehicleto- roadside communications is infrequent, interrupted, or simply not possible. These attributes characterize a sparse VANET, and are characteristic of delay tolerant networks (DTNs). In this paper, we examine the challenges of VANETs in sparse network conditions, review alternatives including epidemic routing and propose a Border node Based Routing (BBR) protocol for partially connected VANETs. Unlike many VANET protocols that assume location awareness or mobility patterns to aid in routing decisions, BBR is designed to function in domains where location and mobility information is not available, as is typical in rugged terrain conditions. The BBR protocol can tolerate network partition due to low node density and high node mobility. The performance of this protocol is evaluated in OPNET TM with a Random Waypoint mobility model and a Geographic and Traffic Information (GTI) based mobility model that captures typical highway conditions. The simulation results are compared with those obtained using the Dynamic Source Routing (DSR) protocol and with an epidemic routing protocol. The simulation results show that BBR performs well for partially connected VANETs where other protocols fail and provides the advantage of not relying on a location service required by other protocols proposed for VANETs.

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.

Intermittently connected opportunistic networks experience frequent disconnections and shorter contact durations. Therefore routing of messages towards their destinations needs to be handled from various points of view. Predictability and connectedness are two information which can be determined by participating mobile nodes of an opportunistic content distribution network using their past contacts. Epidemic or probabilistic routing protocols do not fully utilize these information to route messages towards their destinations. In this paper we describe the routing algorithm, implementation details, experiment design and the performance validation of a new, adaptive routing protocol which utilizes the predictability and connectedness information to route messages efficiently. Simulation based comparative studies show that the proposed routing protocol outperforms existing Epidemic and probabilistic routing protocols in delivering messages.

Vehicular ad hoc networks (VANETs) are known for highly mobile and frequently disconnected characteristics. In this paper, we propose a new epidemic routing protocol in urban environment called Greedy Zone Epidemic Routing (GZER), in which neighbors of a vehicle are divided into different zones according to their physical locations. In each zone, the infection is decided by the zone summary vector. Simulation results show that GZER has compatible delivery ratio with the Epidemic Routing under low vehicle density or light packet traffic load settings, while it has a much better performance in all metrics under high vehicle density together with heavy packet traffic load settings.

In previous work, we proposed a Message Suppression (MS) method for Vehicular Delay Tolerant Networking (Vehicular-DTN) considering Epidemic routing protocol. In this paper, we evaluate our proposed MS method considering three different DTN routing protocols under highly stressed environment. In order to evaluate the performance of MS method, we use Direct Delivery, Spray and Wait and Epidemic as DTN routing protocols. The simulations for two scenarios are conducted considering obstacles (buildings), where MS with Road side units (MSRs) are present and not present. We consider 802.11p standard and send bundle messages in a Manhattan grid scenario. We use the packet delivery ratio, end-to-end delay, number of replicated messages and storage usage as evaluation metrics. Based on simulation results, we found that our proposed method with Epidemic routing has better performance compared with other DTN routing protocols.

Delay tolerant networks (DTNs) are wireless networks where disconnections may occur frequently due to node mobility, power outages and propagation phenomena. To achieve date delivery, store-and-forward protocols are used in DTN and routing protocols based on epidemic message dissemination have been proposed, like epidemic routing. Under epidemic routing, messages can be delivered completely between every two nodes if every node buffer is big enough and the communication time is long enough after one node contacts another. But congestion will occur easily at a node if the buffer of this node is limited under epidemic routing in DTN. To solve this problem, a novel congestion control strategy is introduced. The strategy is called N-DC (drop the copying numbers over N). By using simulations based on a Random Waypoint model, the simulation results proved the improvement of this strategy.

Epidemic protocols belong to a class of routing paradigm that have wide ranging applications in Delay Tolerant Networks (DTNs) due to their simplicity, low delays, and little to no reliance on special nodes. To this end, a comprehensive study of their performance will serve as an important guide to future protocol designers. Unfortunately, to date, there is no work that studies epidemic routing protocols using a common framework that evaluates their performance objectively using the same mobility model and parameters. To this end, we study four categories of epidemic routing protocols. Namely, P-Q epidemic, epidemic with Time-To-Live (TTL), epidemic with Encounter Count (EC) and epidemic with immunity table. Our results show that the probability of transmissions as used in P-Q epidemic may increase delay and decrease delivery ratio. Apart from that, an incorrect TTL value leads to premature discarding of bundles, and thereby, has a non negligible impact on delivery ratio. Epidemic with EC suffers from high buffer occupancy levels and long delivery delays. In addition, epidemic with immunity suffers from high overheads. Henceforth, we propose three enhancements: dynamic TTL, EC+TTL and cumulative immunity to address the aforementioned limitations. Our results show that dynamic TTL improves delivery ratio by more than 20%, EC+TTL reduces buffer occupancy level by 40%, and improve delivery ratio by at least 40% at high loads. Cumulative immunity reduces the buffer occupancy level of nodes by at least 15% whilst in curing an order of magnitude less signaling overheads.

In this paper, we modify and extend epidemic routing used in intermittent networks such as delay tolerant networks (DTNs). In particular, we propose to include immunity-based information disseminated in the reverse direction once messages get delivered to their destination. There are many variants of epidemic routing that are intended to result in better resource utilization by reducing the number of copies or through the use of sophisticated forwarding policy. Our focus is to use the information of already delivered messages in an immunity-list that will prevent any future exchange of those messages. Through the use of this technique we expect that the percent of delivered messages at lower delays will be higher because of better buffer and network utilization. Our simulation shows statistically significant performance improvement both in delivery ratio and delay for immunity-based epidemic as compared to the basic epidemic protocol.

Information dissemination is one of the most important aspects of routing mechanisms for network management. We study in this paper the problem of disseminating an information by a source trough all the nodes of a network. We consider an epidemic routing protocol in an Ad hoc network with a delayed feedback to the source. Indeed, the source controls the dissemination of the information in the network by sending an anti-packet, like a vaccine. We show that there exists a sufficient condition for stability of the information dissemination in the network depending on the spreading of information in the network and the delay of the feedback to the source.

Delay Tolerant Networks allow communication services under highly mobile and intermittent connectivity. DTNs can overcome the problem of high mobility and disconnections based on the store-carry and forward principle and releasing many copies of the same message. In this paper we model the message's propagation in epidemic routing and we derive the optimal duration that a node can holds a message for forwarding it to other relays.

In this paper, we first challenge the accuracy of the so-called innovative assumption that is widely adopted in delay performance analysis of network-coding-based epidemic routing (NCER) in delay-tolerant networks (DTNs). We demonstrate that this optimistic assumption severely underestimates data delivery delay and solves this problem successfully by introducing an extra encounter factor δ. Based on this, we propose a coloring process (CP)-based analytical model to evaluate the delay performance of NCER. Numerical results show that our CP-based method outperforms traditional ordinary differential equation (ODE)-based methods on estimating the delay performance under different network sizes. Furthermore, to mitigate potential competition among multiple data streams from different nodes, we propose a feedback-based recovery protocol (FRP) that takes advantage of finite buffer space and significantly reduces the number of ineffective transmissions between nodes. As a result, FRP can achieve much better delay performance compared with existing protocols in prior work.

We consider the problem of joint dissemination of multiple contents with different priorities through epidemic routing in a large Delay Tolerant Network (DTN). Specifically, we consider two files a and b to be distributed in a large capacity-limited DTN through opportunistic contacts between the roaming nodes. The goal is to maximize the number of nodes that receive the files within a delay window, but with a priority for file b over file a. This preference can reflect difference in popularity or significance of files, or offering different grades of service. The restriction is the short duration of encounters and limited transmission capacity of nodes, where decisions have to be made on which file to forward upon an opportunity of communication. By formulating this problem as an optimal control problem based on ordinary differential equations and analyzing it through Pontryagin's Minimum Principle, we find that the optimal routing policies follow a simple but a priori counter-intuitive "bang-singular-bang" structure. Through numerical evaluations, we illustrate our findings and provide some intuitions about how the structure of the optimal policy changes with respect to different network settings.

Routing in Delay Tolerant Networks (DTN) requires nodes to work in a cooperative way. Due to the selfishness nature, the nodes are not willing to use their energy to help others. But two nodes with some relations (friends) are more willing to help each other. In addition, two nodes (not friends) having mutual friends can get help from each other through these mutual friends. This paper proposes a theoretic framework to evaluate the impact of mutual friends on Epidemic Routing (ER). Because the limited energy of nodes will influence their delivery decisions, we establish a model to evaluate the load distribution of ER. Simulations based on real motion traces are made and results show the accuracy of these two models. Further more, for the load distribution, numerical simulations are also considered and results show that most nodes in ER algorithm forward fewer times and only fewer nodes forward more than 5 times.