Epidemic Routing In Delay Tolerant Networks Research Articles

Performance modeling of data transmission by using random linear network coding in DTNs

SummaryIn Delay Tolerant Networks (DTNs), mobile nodes exploit encounter chances to transmit data via the established opportunistic link between encounter nodes. The transmission capacity between two encounter nodes is constrained by the duration of opportunistic links. How to transmit data efficiently is one of the fundamental and most important issues in DTNs. Recently, Random Linear Network Coding (RLNC) is proposed as a promising approach to improve data transmission efficiency in DTNs. To facilitate the development of deployment of RLNC based routing protocols, it is imperative to quantify the performance gain brought by RLNC in a rigorous and systematic way. In this paper, we develop an analytical model to evaluate the data transmission performance of RLNC based epidemic routing in DTNs. In the model, we consider that multiple unicast communication sessions compete for limited \capacity. Numerical results validate the effectiveness of our analytical model and demonstrate the significant performance improvement for data transmission in DTNs brought by RLNC. Our work of this paper provides a general tool for performance evaluation and useful guidelines for designing RLNC based routing protocols in DTNs. Copyright © 2015 John Wiley & Sons, Ltd.

Performance analysis of hop‐limited epidemic routing in DTN with limited forwarding times

SummaryBecause of the uncertainty of transmission opportunity in delay tolerant networks (DTN), routing algorithms in DTN often need nodes to serve as relays for others to carry and forward messages. One classic policy is the Epidemic routing (ER) algorithm. To reduce the overhead, the hop‐limited ER protocol is proposed. This method can get better performance through controlling the message hop count. However, because of the energy constraint or other factors, each node may forward only limited times, that is, both the message hop count and the forwarding times may be limited. This paper proposes a unifying framework to evaluate the performance of ER with the aforementioned constraints. Simulations based on both synthetic and real motion traces show the accuracy of the framework. In addition, we explore the impact of many parameters (e.g., message hop count) through extensive numerical results. For example, numerical results show that both the message hop count and the forwarding times can have certain impact on the routing performance, but their impact is related with many other factors (e.g., the number of nodes). Copyright © 2014 John Wiley & Sons, Ltd.

A novel congestion control strategy in DTN

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.

Evaluating the Impact of Social Selfishness on the Epidemic Routing in Delay Tolerant Networks

To cope with the uncertainty of transmission opportunities between mobile nodes, Delay Tolerant Networks (DTN) routing exploits opportunistic forwarding mechanism. This mechanism requires nodes to forward messages in a cooperative and altruistic way. However, in the real world, most of the nodes exhibit selfish behaviors such as individual and social selfishness. In this paper, we investigate the problem of how social selfishness influences the performance of epidemic routing in DTN. First, we model the message delivery process with social selfishness as a two dimensional continuous time Markov chain. Then, we obtain the system performance of message delivery delay and delivery cost by explicit expressions. Numerical results show that DTN is quite robust to social selfishness, which increases the message delivery delay, but there is more reducing of delivery cost.