Orion Routing Protocol for Delay-Tolerant Networks

In this paper, we address the problem of efficient routing in delay tolerant network. We propose a new routing protocol dubbed as ORION. In ORION, only a single copy of a data packet is kept in the network and transmitted, contact by contact, towards the destination. The aim of the ORION routing protocol is twofold: on one hand, it enhances the delivery ratio in networks where an end-to-end path does not necessarily exist, and on the other hand, it minimizes the routing delay and the network overhead to achieve better performance. In ORION, nodes are aware of their neighborhood by the mean of actual and statistical estimation of new contacts. ORION makes use of autoregressive moving average (ARMA) stochastic processes for best contact prediction and geographical coordinates for optimal greedy data packet forwarding. Simulation results have demonstrated that ORION outperforms other existing DTN routing protocols such as PRoPHET in terms of end-to-end delay, packet delivery ratio, hop count and first packet arrival

Pervasive intelligent routing in content centric delay tolerant networks

This paper introduces a Swarm-Intelligence based Routing protocol (SIR) that aims to efficiently route information in content centric Delay Tolerant Networks (CCDTN) also dubbed pocket switched networks. First, this paper formalizes the notion of optimal path in CCDTN and introduces an original and efficient algorithm to process these paths in dynamic graphs. The properties and some invariant features of these optimal paths are analyzed and derived from several real traces. Then, this paper shows how optimal path in CCDTN can be found and used from a fully distributed swarm-intelligence based approach of which the global intelligent behavior (i.e. shortest path discovery and use) emerges from simple peer to peer interactions applied during opportunistic contacts. This leads to the definition of the SIR routing protocol of which the consistency, efficiency and performances are demonstrated from intensive representative simulations

HYMAD: Hybrid DTN-MANET Routing for Dense and Highly Dynamic Wireless Networks

In this paper we propose HYMAD, a Hybrid DTN-MANET routing protocol which uses DTN between disjoint groups of nodes while using MANET routing within these groups. HYMAD is fully decentralized and only makes use of topological information exchanges between the nodes. We evaluate the scheme in simulation by replaying real life traces which exhibit this highly dynamic connectivity. The results show that HYMAD outperforms the multi-copy Spray-and-Wait DTN routing protocol it extends, both in terms of delivery ratio and delay, for any number of message copies. Our conclusion is that such a Hybrid DTN-MANET approach offers a promising venue for the delivery of elastic data in mobile ad-hoc networks as it retains the resilience of a pure DTN protocol while significantly improving performance.Comment: 7 pages, 6 figure

Routing in Delay Tolerant Networks

Delay-tolerant networks (DTNs) have the great potential to connecting devices and regions of the world that are presently under-served by current networks. A vital challenge for Delay Tolerant Networks is to determine the routes through the network without ever having an end to end path, or knowing which routers will be connected at any given instant of time. The problem has an added constraint of limited size of buffers at each node. This situation limits the applicability of traditional routing techniques which categorize lack of path as failure of nodes and try to seek for existing end-to-end path. Approaches have been proposed which focus either on epidemic message replication or on previously known information about the connectivity schedule. The epidemic approach, which is basically a flooding technique, of replicating messages to all nodes has a very high overhead and does not perform well with increasing load. It can, however, operate without any prior information on the network configuration. On the other hand, the alternatives, i.e., having a prior knowledge about the connectivity, seems to be infeasible for a self-configuring network. In this project we try to maximize the message delivery rate without compromising on the amount of message discarded. The amount of message discarded has a direct relation to the bandwidth used and the battery consumed. The more the message discarded more is the bandwidth used and battery consumed by every node in transmitting the message. At the same time, with the increase in the number of messages discarded, the cost for processing every message increases and this adversely affects the nodes. Therefore, we have proposed an algorithm where the messages are disseminated faster into the network with lesser number of replication of individual messages. The history of encounter of a node with other nodes gives noisy but valuable information about the network topology. Using this history, we try to route the packets from one node to another using an algorithm that depends on each node’s present available neighbours/contact and the nodes which it has encountered in the recent past. We have also focused on passing the messages to those nodes which are on the move away from the source/forwarder node, as the nodes moving away have a greater probability of disseminating the messages throughout the network and hence increases chances of delivering the message to the destination

A Taxonomy on Misbehaving Nodes in Delay Tolerant Networks

Delay Tolerant Networks (DTNs) are type of Intermittently Connected Networks (ICNs) featured by long delay, intermittent connectivity, asymmetric data rates and high error rates. DTNs have been primarily developed for InterPlanetary Networks (IPNs), however, have shown promising potential in challenged networks i.e. DakNet, ZebraNet, KioskNet and WiderNet. Due to unique nature of intermittent connectivity and long delay, DTNs face challenges in routing, key management, privacy, fragmentation and misbehaving nodes. Here, misbehaving nodes i.e. malicious and selfish nodes launch various attacks including flood, packet drop and fake packets attack, inevitably overuse scarce resources (e.g., buffer and bandwidth) in DTNs. The focus of this survey is on a review of misbehaving node attacks, and detection algorithms. We firstly classify various of attacks depending on the type of misbehaving nodes. Then, detection algorithms for these misbehaving nodes are categorized depending on preventive and detective based features. The panoramic view on misbehaving nodes and detection algorithms are further analyzed, evaluated mathematically through a number of performance metrics. Future directions guiding this topic are also presented

Opportunistic lookahead routing procedure for delay tolerant networks

Delay Tolerant Networks are wireless networks that have sporadic network connectivity, thus rendering the existence of instantaneous end-to-end paths from a source to a destination difficult or impossible. Hence, in such networks, message delivery relies heavily on the store-and-forward paradigm to route messages. However, limited knowledge of the contact times between the nodes poses a big challenge to effective forwarding of messages. In this thesis, we discuss several aspects of routing in DTNs and present one algorithm and three variants for addressing the routing problem in DTNs: (i) the Look-ahead Protocol, in which the forwarding decision at each node to its immediate or one-hop neighbor is based on the position of the packet / message in the queue of the neighboring node(ii) Backpressure based lookahead, where a lookahead factor is introduced with the basic backpressure equation. This factor takes into account the difference of queue lengths from the neighbors, (iii) a two-step lookahead protocol, where the forwarding decision is sometimes based on the instantaneous one-hop neighbors of the neighboring node. We also present simulation results of these protocols and compare these results to the existing standard routing protocols for DTNs. In all the algorithms, we look to optimize the amount of network bandwidth used by looking one step ahead before making a forwarding decision. By considering the queue in the neighboring nodes, the amount of network resources consumed decreases. The protocols that we propose may come with a slightly higher hop-count per packet than most protocols, but we have tried to maintain a comparable delivery ratio with the existing standard protocol