Delay/Disruption Tolerant Networks Research Articles

FAPMIC: Fake Packet and Selective Packet Drops Attacks Mitigation by Merkle Hash Tree in Intermittently Connected Networks

Delay/Disruption Tolerant Networks (DTNs) are a special category of IntermittentlyConnectedNetworks (ICNs). It has features such as long-delay, frequent-disruption, asymmetrical-data-rates, and high-bundle-error-rates. DTNs have been mainly developed for planet-to-planet networks, commonly known as Inter-Planetary-Networks (IPNs). However, DTNs have shown undimmed potency in challenged communication networks, such as DakNet, ZebraNet, KioskNet and WiderNet. Due to unique characteristics (Intermittent-connectivity and long-delay) DTNs face tough/several challenges in various research areas i.e bundle-forwarding, key-distribution, privacy, bundle-fragmentation, and malicious/selfish nodes particularly. Malicious/selfish nodes launch various catastrophic attacks, this includes, fake packet attacks, selective packet drops attacks, and denial-of-service/flood attacks. These attacks inevitably consume limited resources (persistent-buffer and bandwidth) in DTNs. Fake-packet and selective-packet-drops attacks are top among the challenging attacks in ICNs. The focus of this article is on critical analyses of fake-packet and selective-packet-drops attacks. The panoramic view on misbehavior nodes mitigation algorithms are analyzed, and evaluated mathematically through several parameters for detection probability/accuracy. This article presents a novel algorithm to detects/mitigates fake-packet and selective-packet-drops attacks. The proposed algorithm uses Merkle-Hash-Tree to detects the aforementioned attacks. The proposed algorithm added root hash along with all packets, when the malicious nodes drop packets or inject fake packets, the algorithm detects malicious nodes. Moreover, trace-driven simulation results show the proposed algorithm of this article accurately (enhanced detection-accuracy, enhanced packet delivery/packet loss ratios, and reduces false-positive/false-negative rates) detects malicious nodes which launch fake-packet and selective-packet-drops attacks, unlike previously proposed algorithms which detect only one attack (fake-packet or packet-drops at a time) or detect only malicious path (do not exactly detect malicious nodes which launch attacks). Furthermore, this article mathematically analyzed various scenarios to track exactly/position of various vehicular nodes.

A Study of Licklider Transmission Protocol in Deep-Space Communications in Presence of Link Disruptions

Delay/disruption-tolerant networking (DTN) is widely recognized as a key internetworking technology for implementing a space system of systems (SoS). Aimed at being the main data transport protocol of DTN, Licklider transmission protocol (LTP) is expected to provide reliable data transmission service in a challenging space SoS networking environment regardless of random link disruptions. In this paper, a study of LTP in deep-space communication networks in presence of link disruptions is presented. An analytical framework is developed for the effect of multiple random link disruptions on LTP's reliable data delivery in deep-space networks. The study indicates that the models accurately predict the transmission performance of LTP over a deep-space communication channel in presence of multiple link disruptions. A threshold interval value, obtained from the analytical modeling results, is proposed as a means of determining the reducibility of two successive link disruptions to a single disruption; that threshold value is verified by the experiments.

NoD: A content retrieval scheme for intermittently-connected IoT networks

In recent years, Internet of Things (IoT) devices have been deployed even to the most isolated and hard-to-reach areas. Content retrieval from such communication-disruptive remote areas therefore becomes a challenging task, mainly due to the increased infrastructure cost. In this paper, we present a gateway-oriented scheme which facilitates content retrieval from remote IoT deployments, using mobile devices. We call our scheme NDN-over-DTN (NoD), as it combines the information-centric design of the Named Data Networking (NDN) architecture with the store-carry-and-forward approach of Delay/Disruption-Tolerant Networking (DTN). In this work, we evaluate the performance of NoD in a real IoT-content-retrieval scenario, in terms of Average Delay, Cache Hit, Interest Satisfaction and Overhead Ratio. We model the behavior of NoD analytically and introduce an improved NoD version which utilizes cross-layer interaction between NDN and DTN, called NoD-Discovery. We show, both analytically and experimentally, that NoD can exploit jointly the benefits of NDN and DTN and achieve significant performance gains in highly disruptive environments. Notably, our experiments demonstrated that NoD-Default can achieve up to a 48.77% decrease in Average Delay compared to host-centric DTN, while NoD-Discovery can improve performance further by decreasing the Overhead Ratio up to 70.34%, compared to the original NoD-Default implementation.

A Study of Link Disruption on BP From Spatial and Temporal Perspectives in Deep-Space Vehicle Communications

Developed as the main protocol of delay/disruption-tolerant networking (DTN) for space, bundle protocol (BP) is intended to establish an overlay network for reliable data delivery in a heterogeneous networking environment. The effect of a link disruption on reliable data transmission of BP is currently under study. In this paper, a study of the effect of link disruption on BP's reliable data delivery in deep-space vehicle communications, from spatial and temporal perspectives, is presented employing both analytical and experimental methods. The effect is modeled in various transmission cases by considering the physical distance the bundle has traversed when the link disruption starts and ends, the duration of link disruption in time, and the physical span of the link disruption. The models are built to quantify the number of transmission attempts that fail due to link disruption, the total number of transmission attempts, bundle delivery time, and transmission goodput performance for successful bundle delivery in presence of a link disruption. The models are validated by realistic bundle delivery over a PC-based experimental testbed. The validation indicates that the analytical models predict the transmission performance of BP in presence of random link disruption in various aspects of successful bundle delivery.

Toward Pre-Empted EV Charging Recommendation Through V2V-Based Reservation System

Electric vehicles (EVs) are being introduced by different manufacturers, thanks to their environment-friendly perspective to alleviate CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> pollution. In this paper, the proposed EV charging management scheme enables pre-empted charging service for heterogeneous EVs (depends on different charging capabilities, brands, etc.). Particularly, the anticipated EVs' charging reservations information, including their arrival time and expected charging time at charging stations (CSs), are brought for planning CS-selection (where to charge). Along with applying ubiquitous cellular network communication to deliver (delay tolerant) EVs' charging reservations, we further study the feasibility of applying opportunistic vehicle-to-vehicle (V2V) communication with delay/disruption tolerant networking (DTN) nature, due primarily to its flexibility and cost-efficiency in vehicular ad hoc networks (VANETs). Evaluation results under the realistic Helsinki city scenario show that applying the V2V-based charging reservation is promisingly cost-efficient in terms of communication overhead, while achieving a comparable charging performance to apply cellular network communication.

Hybrid Retransmissions of Bundle Protocol for Reliable Deep-Space Vehicle Communications in Presence of Link Disruption

Targeted as the main protocol of delay/disruption-tolerant networking (DTN) for space, bundle protocol (BP) is intended to establish an overlay network for reliable file delivery in a heterogeneous networking environment. Reliable data transmission mechanisms of BP are presently under development. In this paper, a new transmission approach is proposed for BP for highly reliable data delivery in deep-space vehicle communications in presence of an unpredictable or random link disruption. The main idea of the proposed approach is to use a hybrid of proactive retransmission and reactive retransmission mechanisms during file transfer. Analytical models are built in various transmission cases to study the effect of link disruption on reliable transmission of BP, with focus on the number of failed transmission attempts, file delivery time and goodput performance normalized with respect to the total amount of data sent. The models are validated by the file transfer experiment over a PC-based testbed. A performance comparison between the proposed approach and the existing transmission approach with respect to transmission reliability is also presented.

Survey on Various DTN Routing Algorithms for Vehicular ADHOC Network (VANET)

Vehicle Adhoc Network (VANET) permits self-organized infrastructure. Link or Connectivity breakage or long delay (intermittent connection) is an important issue in the VANET which arises due to the dynamic topological changes. Mainly two algorithms Vehicle assisted Data Delivery (VADD) and Opportunistic routing algorithm supports for handling delay/disruption tolerant network (DTN). Intention of DTN is to create dynamic link between the sender and receiver vehicle in the case of link disruption or absence of path between two nodes and forwards the data using store carry and forward. VADD carry and forward the data as much as possible in disconnected network using intersection mode, straightway mode or destination mode. Opportunistic routing can deal the unreliable data and intermittent connectivity in VANET by considering the multiple nodes as a next hop forwarder instead of considering pre-selected single node to be the best forwarder. This paper gives the study about various opportunistic routing algorithms for handling delay/disruption tolerant network.

Transmission Efficiency of Licklider Transmission Protocol (LTP) and Bundle Protocol (BP) in DTN Architecture

From Near-Earth orbit (NEO) to Earth-Sun Lagrangian points will continue to be a majority of Near Earth missions ranging from Near-Earth orbit (NEO) to Earth-Sun Lagrangian points will continue to be a majority of future space missions. A few works have been done with delay/disruption tolerant networking (DTN) technology for Near-Earth orbit (NEO)-space center and deep space communications and provided feasibility for its adoption in NEO-space and deep space missions. [1] However, no much work has been done to fully evaluate the transmission efficiency of DTN in such an environment, especially in the presence of long link disruption, data corruption and lost rate, and link asymmetry. In this paper, we present an experimental performance evaluation of DTN architecture and protocol stack, with Licklider transmission protocol (LTP) serving as a convergence layer adapter (CLA) underneath bundle protocol (BP), in typical NEO-satellite system and deep space communication infrastructures accompanied by a very long link delay, various packet corruption and lost rates, and channel rate symmetry and asymmetry. In addition, we present an experimental research of the transmission efficiency of DTN custody transfer with long link delay. The experiment was conducted by performing realistic file transfers over a virtual server-based test-bed.

Nanosatellite-5G Integration in the Millimeter Wave Domain: A Full Top-Down Approach

This paper presents a novel network architecture for an integrated nanosatellite (nSAT)-5G system operating in the millimeter-wave (mmWave) domain. The architecture is realized adopting a delay/disruption tolerant networking (DTN) approach allowing end users to adopt standard devices. A buffer aware contact graph routing algorithm is designed to account for the buffer occupancy of the nSATs and for the connection planning derived from their visibility periods. At the terrestrial uplink, a coded random access is employed to realize a high-capacity interface for the typically irregular traffic of 5G users, while, at the space uplink, the DTN architecture is combined with the contention resolution diversity slotted Aloha protocol to match the recent update of the DVB-RCS2 standard. To achieve a reliable testing of the introduced functionalities, an accurate analysis of the statistic of the signal to interference-plus-noise ratio and of the capture probability at each mmWave link is developed by including interference, shadowing, fading, and noise. The application of the designed architecture to data transfer services in conjunction with possible delay reduction strategies, and an extension to inter-satellite communication, are finally presented by estimating the resulting loss/delay performance through a discrete-time discrete-event platform based on the integration of Matlab with Network Simulator 3.

Geo-DMP: A DTN-Based Mobile Prototype for Geospatial Data Retrieval

Geospatial information is gaining immense interest and importance as we enter the era of highly developed transportation and communication. Despite the proliferation of cellular network and WiFi, on some occasions, users still face barriers to accessing geospatial data. In this paper, we design and implement a distributed prototype system with a delay/disruption tolerant network (DTN), named Geo-DMP, for cooperatively and opportunistically sharing and exchanging named geospatial contents in a device-to-device fashion. First of all, we construct a lightweight “content agent” module to bridge the gap between the application layer and the underlying DTN protocol stack. Afterwards, to profile the mobility history of users in practical geospatial environments, we present a map segmentation scheme based on road network and administrative subdivision information. Subsequently, we associate the regional movement history information with the content retrieval process to devise a hierarchical and region-oriented DTN routing scheme for both requests and responses. Finally, we conduct extensive experiments with real-world trajectories and complete implementations on the emulation platform composed of virtual machines. The experiments corroborate that Geo-DMP has the capability of successfully retrieving geospatial contents for users for most of the time under mobile circumstances with episodic connectivity. Moreover, en-route caches can be efficiently exploited to provision contents from multiple sources with less network resource consumption and shorter user-perceived latencies.

Performance of Bundle Protocol (BP) for deep space communications with long link disruptions

Near Earth missions and deep space missions will continue to be a major future space mission. A long link disruption is inevitable in space communications because of spacecraft rotation, planetary bodies and limited relay capability. A few works have been done with delay/disruption tolerant networking (DTN) technology for deep space communications and provided feasibility for its adoption in LEO- space and deep space missions. However, not much work has been done to fully evaluate the performance of DTN in such an environment, especially in the presence of custody and long link transfer. In this article, we present an experimental performance evaluation of DTN architecture and protocol stack with DTN custody transfer and long link break underneath bundle protocol (BP), in typical LEO-satellite and deep space communication infrastructures accompanied. The experiment was conducted by performing realistic file transfers over a PC-based test-bed.

An Improved Routing Algorithm for Mobile Opportunistic Networks using a Genetic Approach

Background/Objectives: Nowadays, Mobile Opportunistic Networks (MONs) are counted as one of the most interesting development of MANETs. In MONs, forwarding messages through mobile nodes is a big challenging research problem. Methods/Analysis: In this study, an optimization technique that based on a Genetic Algorithm (GA) is proposed. It is oriented towards solving most issues faced in Delay/Disruption Tolerant Network (DTN) routing such as there is no end to end connectivity between nodes, long delay for transmission message in path, congestion during sending the message and more. Findings: The proposed technique outperforms the other state-of-art methods regarding to delivery ratio, message transmission delay and message overhead ratio. Application/Improvements: Compared to the state-of art methods, the results show that our proposed algorithm has a better performance in terms of message delivery ratio and message transmission delay, and message overhead ratio.

Analysis of Licklider Transmission Protocol for Reliable File Delivery in Space Vehicle Communications With Random Link Interruptions

Delay/disruption tolerant networking (DTN) was proposed as a networking architecture for reliable data delivery in space vehicle communications despite long propagation delays and/or lengthy link disruptions. As one of the main data transport protocols of DTN, Licklider transmission protocol (LTP) was proposed by the NASA for reliable data delivery in challenging space environments in which the existing transport protocols of DTN, TCP, and UDP do not perform effectively. Pair-wise comparisons among LTP, TCP, and UDP running in the DTN stack have previously been done using statistical methods; evaluation results and performance analysis are available in the existing LTP research literature. However, there is as yet no solid analytical model of LTP performance in the presence of link disruptions. In this paper, we present an analytical method to predict transmission performance of LTP for reliable file delivery in space vehicle communications with focus on the expected file delivery delay (or latency) over space channels characterized by random link disruptions. Realistic file-transmission experiments using a PC-based infrastructure are presented to validate the analytical models. The analysis and study results presented in this paper are expected to be useful in understanding the impact of transmission conditions and configurations, on the efficiency of LTP when deployed for reliable data delivery in space missions using communication links that are subject to frequent and random interruptions.

A cross-layer QoS model for space DTN

Delay/disruption tolerant networking (DTN) technology is considered as a new solution for highly stressed communications in space environments. IP-based DTN network can support more flexible communication services, which is one of the research hotspots of space networking. At the same time, it is still an important and difficult problem to optimise the limited network resources allocation and guarantee the QoS of different services in DTN network. For this challenge, a cross-layer QoS model that considers application, network, and node layer QoS requirements and resource limitations is proposed in this paper. In addition, a comprehensive admission control scheme that ensures productivity and fairness is employed. The results of experiments and analyses conducted demonstrate the benefits to be derived from this approach.

ORIT: A Transport Layer Protocol Design for Underwater DTN Sensor Networks

Research challenges have focused on underwater acoustic sensor networks characterized by long propagation delay, narrow bandwidth, and frequently disconnected interruption, among others, which can be viewed as delay/disruption tolerant networks (DTNs). However, limited research has been conducted on goodput performance considering the total data packets transmitted in the channel, which is referred to as the remove redundant goodput (RRG) performance of underwater DTN sensor networks. In this paper, we propose a transport layer protocol, called optimal retransmission timeout (RTO) interval stop-and-wait transmission (ORIT), used in underwater DTN sensor networks. In most general transport layer protocols, the RTO timer is set to longer than the RTT to avoid pseudo-retransmissions. However, great network latency could be introduced by applying such a mechanism in underwater communication networks. In ORIT, we propose an RTO optimization algorithm to maximize the RRG performance of the network by reducing the RTO timer. Meanwhile, we adopt the interval stop-and-wait transmission mechanism to avoid data pseudo-retransmissions caused by setting the RTO timer shorter than the RTT in narrow acoustic channels. Through adopting the RTO timer, the ORIT can achieve the best RRG performance under an RTO timer, which we call the optimal RTO timer. We compare the ORIT with other transport layer protocols in the DTN network. The results show that the ORIT with the optimal RTO timer can shorten the long propagation delay and effectively increase the data delivery rate in the underwater DTN sensor networks.

Employing Social Cooperation to Improve Data Discovery and Retrieval in Content-Centric Delay-Tolerant Networks

The paradigm of Content-Centric Networks (CCN) has been used in several networking application contexts in order to enhance the performance of data forwarding and retrieval. By disassociating device addressing from the packet routing process, CCN offers new message routing possibilities in network scenarios that are limited in this respect. An example of such scenarios concerns Delay/Disruption Tolerant Networks (DTNs), in which requesting and retrieving data and services may be even more unpredictable than simply sending any message from a source to a destination. With this in mind, we propose a DIscovery and REtrieval protocol based on Social Cooperation (DIRESC), designed specifically to perform data request and retrieval by applying the concept of CCN in the DTN scenario, an environment also known as Content-Centric Delay-Tolerant Networks (CCDTN). Our forwarding mechanism proposes the distributed sending of data based on the profile of each node, which is defined by its social interactions with other nodes. To evaluate our protocol, we used the Opportunistic Network Environment (ONE) simulator to compare DIRESC to other related CCDTN protocols, including our conceptual implementation of content-centric forwarding dubbed CCN broadcast. Results show that social cooperation has positive performance impact (i.e., improved delivery rate, delay, overhead, packet retransmission, and energy consumption) when compared to other social-oblivious CCDTN protocols.

Queueing analysis of DTN protocols in deep-space communications

Delay/disruption tolerant networking (DTN) [1] is proposed as an internetworking architecture for reliable data delivery despite a long propagation delay and/or lengthy link disruptions. DTN targets challenging networking environments where traditional networking protocols such as the terrestrial Transmission Control Protocol/Internet Protocol (TCP/IP) typically do not work effectively. The challenging problem of mission control and data delivery in space communications is a typical application scenario of the DTN technology. Reliable and highly efficient data delivery of DTN relies heavily on the bundle protocol (BP) [2]. BP is intended to establish an overlay network that is able to withstand intermittent data link connectivity in the delivery of DTN data units, termed bundles. BP adopts a store-and-forward mechanism and a custody transfer option for transmission reliability.

A Trajectory-Driven Opportunistic Routing Protocol for VCPS

By exploring sensing, computing, and communication capabilities on vehicles, vehicular cyber-physical systems (VCPS) are promising solutions to provide road safety and traffic efficiency in intelligent transportation systems. Due to high mobility and sparse network density, VCPS could be severely affected by intermittent connectivity. In this paper, we propose a trajectory-driven opportunistic routing (TDOR) protocol, which is primarily applied for sparse networks, e.g., delay/disruption tolerant networks (DTNs). With geographic routing protocol designed in DTNs, existing works primarily consider the proximity to destination as a criterion for next-hop selections. Differently, by utilizing GPS information of on-board vehicle navigation system to help with data transmission, TDOR selects the relay node based on the proximity to trajectory. This aims to provide reliable and efficient message delivery, i.e., high delivery ratio and low-transmission overhead. TDOR is more immune to disruptions, due to unfavorable mobility of intermediate nodes. Performance evaluation results show TDOR outperforms well-known opportunistic geographic routing protocols, and achieves much lower routing overhead for comparable delivery ratio.

Modeling Optimal Retransmission Timeout Interval for Bundle Protocol

Delay/disruption tolerant networking (DTN) was proposed as a networking architecture for reliable data delivery despite an extremely long propagation delay and frequent/lengthy link disruptions. The challenging problem of mission control and data delivery in deep-space explorations is a typical application scenario of the DTN technology. Reliable data delivery of DTN relies heavily on its core bundle protocol (BP). Performance evaluation and improvement of BP for deep-space communications are presently underway. The setting of the retransmission time-out (RTO) timer of BP is critical for reliable and highly efficient file transfer in a deep-space communication environment. In this paper, we present analytical modeling of an optimal RTO timer interval for the best goodput performance of BP in deep-space communications characterized by a very long signal propagation delay and lossy data links. A model is developed to compute the RTO timer interval that will result in the best goodput performance of BP normalized with respect to the total data load transmitted in order to achieve successful delivery of an entire file. Experimental validation using a PC-based testbed indicates that the RTO timer interval indicated by the model achieves the best normalized goodput performance of BP. The model predicts performance in all the experimented scenarios.

Managing Hierarchically Structured DTN-Like Networks

Network management in Delay/Disruption Tolerant Networks (DTNs) is an active research topic and covers topics such as system architecture, roles of actors, and management protocol. The existing solutions either expect a flat management hierarchy or do not address the hierarchical structure used in management. However, in many real-world DTN use cases, particularly in emergency and military contexts, the actors using the DTN system are a part of an organizational or operational hierarchy, and the network design and topology follow the hierarchical structure. This paper introduces a DTN management scheme that is based on that hierarchy. The paper presents a node categorization that is based on the hierarchy, the characteristics of the hierarchical management, roles and responsibilities of the managed and managing nodes in the hierarchy, and the related concept of management responsibility stack. Further, the paper discusses the characteristics of the messaging and configurability of the nodes in a hierarchical network, and introduces a problem called DTN management trilemma. The paper also presents a use case where the concepts of this paper are applied to network management of a hierarchical organization in a reference scenario, and the performance of the hierarchical management methods is compared to an equivalent nonhierarchical solution.