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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.

To solve the problems of LEO (Low Earth Orbit) satellite network, such as insufficient flexibility and low resource utilization, an architecture using network slicing technology is proposed. Then a prototype system based on the Docker platform and DTN (Delay Tolerant Network) is implemented, providing IMS (IP Multimedia Subsystem) network slice, Internet of Things network slice and web network slice. Tested by prototype system, the results show that each network slice can independently provide relevant service without affecting each other, and can be allocated network resources flexibly according to the performance requirements of the services. The architecture can effectively improve the flexibility of the core network of LEO satellite network.

In this paper, we focus on Information-Centric Delay-Tolerant Network (ICDTN), which incorporates the communication paradigm of Information-Centric Networking (ICN) into Delay-Tolerant Networking (DTN). Conventional ICNs adopt a naming scheme that names the content with the content identifier. However, a past study proposed an alternative naming scheme that describes the name of content with the content descriptor. We believe that, in ICDTN, it is more suitable to utilize the approach using the content descriptor. In this paper, we therefore propose keyword-based ICDTN that resolves content requests and deliveries contents based on keywords, i.e., content descriptor, in the request and response messages.

Internet of Things (IoT) applications use a huge number of smart objects, which are connected through various heterogeneous technologies. Moreover, they are characterized by their mobility and unreliability. The main goal of this paper is to present an alternative solution for the intermittently connected IoT network by considering the Delay Tolerant Network (DTN) approach. Through the integration of the functionality of the DTN and Bundle Protocol (BP) in the IoT network layer, the wireless IoT devices exploit the features of DTN in routing and mobility, to transmit data to destination efficiently and to ensure interoperability in the network.

Information on evacuation shelters and routes is important for evacuees to evacuate safely and promptly when a disaster occurs. To take appropriate evacuation routes, evacuees need to gather information on roads that are damaged. However, in large-scale disasters, network infrastructure can be damaged and become unusable in many cases. To solve this problem, some existing studies propose providing evacuation routes by collecting road information from mobile terminals of evacuees by using a delay tolerant network (DTN) without using network infrastructure. However, in the existing works, congestion caused by evacuees concentrating on a specific route is a problem. This congestion is caused by identical evacuation routes being presented to all evacuees. Therefore, in this paper, we propose recommending different routes to evacuees on the basis of evacuee attributes (e.g. age) to alleviate congestion on roads. We numerically evaluate the proposed method by multi-agent simulation (MAS) and show that it achieves a 22% or greater reduction in the average evacuation distance and 44% or greater reduction in the average evacuation time where the number of evacuees was 30% of the daytime population.

The goal of Delay Tolerant Networking (DTN) is to take a collection of heterogeneous, disparate connections between satellites, space assets, ground stations, and ground infrastructure and bring it together into a cohesive, functioning overlay network. Depending on the systems being considered, one can find links with a one-way light time exceeding minutes (and hours), periodic links which can sometimes be predicted by orbital mechanics, and restrictions based on the variety of capabilities built into these systems. These characteristics preclude traditional network models and routing techniques and have classically led to either rigid routing tables or purely probabilistic models. As the deeper underlying structures remain unknown, development of more DTN-optimized algorithms has lacked the necessary foundation. In a continuation of previous work, the goal of this paper is to identify and study these fundamental structures that exist in delay tolerant networks (DTN), with a focus on space networks. The current routing methodology has been to use contact graph routing (CGR) algorithms. CGR models a series of known contacts as a static graph. For CGR to work, this graph must be globally consistent and must have an accurate picture of the network. Because this is a globally controlled structure, there is little room for flexibility in the event of changes to the network which would naturally occur as the network grows. As a response to the desire for flexibility as the network changes, we introduced the mathematical structure known as sheaves to DTNs last year. The tag-line for sheaves is that they are a mathematically precise way of gluing local data together into unique global data. Thus, sheaves lend extra power to traditional models (and routing algorithms) by taking additional information and merging it, in as consistent a manner as possible, with the representation itself. The clearest example of how Earth-bound networks exhibit behavior that is “sheafy” is link state routers, which build a local-to-global picture of their network by gluing local information together into a global network, exactly as a sheaf would do. For routing within delay tolerant networks to truly exploit this structure, a deeper structure than a graph is required. In this paper, we develop sheaves that can work over directed graphs such as temporal flow networks, we construct a sheaf representation for Dijkstra's algorithm, and we outline a construction for routing sheaves capable of modeling multicast scenarios. Finally, there is a section of future work suggesting follow-on research.

The Named Data Networking and Delay Tolerant Networking architectures were originally targeting distinct networking domains: NDN was designed for content retrieval within fixed networks, while DTN was aiming to deliver data in highly-dynamic wireless topologies with intermittent connectivity. In this paper, we argue that the two technologies can complement each other to shape a joint NDN-DTN scheme which can improve data retrieval from intermittently-connected devices, such as IoT and sensor networks in remote areas. We quantify the improvements by using both DTN- and NDN- associated metrics combined in a common analytical framework and show that NDN-DTN can greatly improve the Interest Satisfaction Ratio and Average Delay when compared to a DTN-only approach, especially in environments with a low Delivery Ratio. We verify our results through experiments with intermittently-connected IoT devices and investigate the impact of parameters such as Interest Lifetime, Data Freshness Period and Contact Duration. We conclude that a joint NDN-DTN approach outperforms a legacy DTN -only setup.

This chapter discusses performance-related aspects of delay-tolerant network (DTN) systems by taking a close look at the essential algorithms and mechanisms required to build any DTN implementation. First, metrics that are relevant for the performance of a DTN system are identified. The impact of IO overhead and performance on achievable data rates and transmission frequency is analyzed and the tradeoff between energy efficiency and discovery latency is discussed. Real-world data from implemented systems is presented and, based on the discussed issues and experiences with several DTN systems, suggestions for implementers and system designers will be given.

In this paper, we propose an Adaptive Anti-packet Recovery (AAR) method based on epidemic protocol. Our method can be used in Vehicular Delay Tolerant Networking (DTN). We use conventional Epidemic with recovery function and the proposed AAR method as the message delivery protocols. From the simulation results, we observed that the delivery ratio of proposed AAR is good for dense networks.

DTN is the latest growing technology having unique characteristics such as longer delays, intermittent connectivity and limited resources or constrained resources. Delay tolerant networks is a store and forward method which delivered the messages to the nearest potential forwarder by replicating copies of the original messages. DTN is created to handle long delays in wireless networks and handle the intermittent connectivity. An information at particular node is delivered only if it has higher particular than the current node. DTN is studied and implemented in opportunistic network environment (ONE) simulator. DTN is having characteristics like disconnected paths, long delays, higher mobility, uplinks, and downlinks, which leads to network vulnerabilities. These vulnerabilities lead to the compromisation of nodes and can cause security threats as these compromised nodes can disrupt the routing protocols in the network. DTN is exposed to different network layer attacks. Attacks on network layer like gray hole and black hole attack can destroy the topology of the network resulting in loss of data and damage to the network. This paper discusses about the black hole, type of black hole attacks, and different detection techniques in delay tolerant networks.

Grup de recerca SENDA (Security of Network and Distributed Applications) In this paper, we introduce software code to improve Delay and Disruption Tolerant Networking (DTN) performance. DTN is extremely useful when source and destination nodes are intermittently connected. DTN implementations use application-specific routing algorithms to overcome those limitations. However, current implementations do not support the concurrent execution of several routing algorithms. In this paper, we contribute to this issue providing a solution that consists on extending the messages being communicated by incorporating software code for forwarding, lifetime control and prioritisation purposes. Our proposal stems from the idea of moving the routing algorithms from the host to the message. This solution is compatible with Bundle Protocol (BP) and facilitates the deployment of applications with new routing needs. A real case study based on an emergency scenario is presented to provide details of a real implementation. Several simulations are presented to prove the feasibility and usability of the system and to analyse its performance in comparison to state-of-the-art approaches.

Conventional routing protocols breaks down in opportunistic networks due to long delays, frequent disconnectivity and resource scarcity. Delay Tolerant Network (DTN) has been developed to cope with these mentioned features. In the absence of connected link between the sender and the receiver, in DTN mobile nodes replicate bundles and work cooperatively to improve the delivery probability. Malicious nodes may flood the network as possible by a huge number of unwanted bundles (messages) or bundle replicas which waste the limited resources. DOS (Denial of Service) attack especially Flooding attack attempt to compromise the availability service of the network. Traditional congestion control strategies are not suitable for DTN, so developing new mechanisms to detect and to control flooding attack is a major challenge in DTN network. In this paper, we presented a comprehensive overview of the existing solutions for dealing with flooding attack in delay tolerant network, and we proposed an effective controlling mechanism to mitigate this threat. The main goal of this mechanism is first to detect malicious nodes that flood the network by unwanted messages, and then to limit the damage caused by this attack. We also ran a large number of simulations with the ONE simulator to investigate how changing buffer capacity, message lifetime, message size, and message replicas affect DTN network performance metrics.

Communication networks operating in challenging environments can be grouped by the concept of Delay/Disruption-Tolerant Networking (DTN). Different protocols can be used in DTN, such as the Bundle Protocol (BP) and the HyperText Transfer Protocol - DTN (HTTP-DTN). In this context, security properties are of fundamental importance in DTN like in regular networks. However, the challenges in DTN hamper the use of traditional security mechanisms. Although BP has been extended to include such mechanisms, there is still no analogous extension for HTTP-DTN. In this paper, we propose the HTTP-DTNSec, a security extension for HTTP-DTN. This extension improves the confidentiality and integrity of HTTP-DTN as well as updates the base protocol for HTTP/2. The proposed extension was implemented as a proof of concept and it was used to perform experiments in a simulated environment. These experiments show that HTTP-DTNSec performed the transfer of packages (i.e., a group of related objects) in a safe manner and with an increase in performance concerning HTTP-DTN. Finally, we provide some concluding remarks and future directions.

Sharing information or simply keeping in touch has become necessary, usually through smartphone messaging applications. However, using these applications is difficult in places where there is no telecommunications infrastructure or transmission channels are saturated. In this context, the use of opportunistic networks is a feasible alternative to provide communication. This type of network takes advantage of the opportunity for contact between mobile devices, as long as users are willing to collaborate. In this article we present a disconnection tolerant messaging application, based on opportunistic networks, using WiFi-Direct, that send/receive text and multimedia messages, allowing the track of messages. The evaluation was carried out considering the transmission time for each type of message in line-of-sight (LOS) and non-LOS (NLOS) scenarios between the devices. The results show the feasibility of using opportunistic networks in smart devices.

The artisanal fishing activity carried out on the coasts where the production of fish can be exploited is affected by a lack of communication between the vessels in order to provide relevant information related to multiple marine sensor parameters. It is mainly due to the rugged geographic area that causes highly disruptive communication links and in which traditional IP-based communications with transport protocols such as TCP or UDP do not work properly. This paper presents and evaluates a new communications architecture to provide services to marine sensor networks using a disruption tolerant networking (DTN) based solution. We propose a new architecture that takes into account the different vessels densities. We assume a finite sensor population model and a saturated traffic condition where every sensor always has frames to transmit. The performance was evaluated in terms of delivery probabilities, delay and a DTN scenario indicator (DSI) proposed. Through simulations, this paper reveals that Low Density scenery yield greater latency, and more density of nodes has better results. We achieved a successful delivery rate of 74% and a latency of 2 h approximately. Finally indicators shows that high density of nodes is strongly recommended for fishery scenery models.

In this paper, we use graph analysis to evaluate the network architecture of a large scale delay tolerant network (DTN) of transoceanic aircraft. At LCN (Local Computer Networks) 2014 we analyzed information propagation inside a pure opportunistic version of this network, a scenario constructed from more than 2,500 traces of transatlantic flights in which communications relied only on the sporadic contacts between airplanes. As only a small percentage of the nodes were capable of performing efficient air-to-ground communications we concluded the need to devise a more suitable network architecture by combining opportunistic and satellite communication systems. We propose a generic methodology based on graph analysis (both static and dynamic temporal) to evaluate the different ways to create this new architecture. We show the architectural combination that most improves the network delivery performance while minimizing its deployment costs.

The standard approach to bundle routing in delay-tolerant networks with predictable contacts uses a graph traversal algorithm to search for paths where the graph’s nodes represent the presumed and non-expired contact opportunities and the edges the waiting time for the next contact to occur. However, unforeseen systemic issues may introduce random contact holdups, i.e., the start time of certain contacts may be delayed, which may lead to lower performance than anticipated. An analysis of random contact holdups and their impact on the probabilistic optimal routing of bundles over parallel, non-overlapping substrate paths are provided. The study brings new insight into the consequences of unforeseen divergences between the planned contacts and their realization, which may help to improve the design of future DTN protocols.

The paper presents the analysis of the Delay Tolerant Network (DTN) methods in an expanding communication network on a railway line. Trains act as moving objects that send and receive messages or collected telemetry data to or from an external network. They can exchange the data with each other, delegating delivery. The paper compares various DTN protocols’ ability to reduce the delay of data delivery and the additional buffer load needed. An analysis is based on the real European railway line example (map and train schedule), with various loads and different coverage of a mobile network. The effectiveness of DTN during migration to networks of a higher data rate (for example, with 5G capabilities) is discussed.

Energy consumption is a significant issue for data forwarding in Delay-Tolerant Network (DTN), where nodes are energy-constrained as they are driven by batteries. During their limited lifetime, these nodes have to spend a huge amount of energy since they perform forwarding, receiving, and temporarily storing messages, searching for the neighboring nodes for message forwarding, etc. The remaining energy of a node is expected to be higher as it increases the possibility of successful message delivery. Hence, awareness of energy expenditure is necessary for the routing strategies in DTN. This issue instigated us to evaluate the impact of node remaining energy on social-based routing protocols for the DTN scenario. Apart from the conventional DTN forwarding techniques, social-based forwarding protocols have involved an emerging concept that considers nodes’ social relations and behaviors to make routing decisions for efficient message transmission. In this paper, we have analyzed the energy efficiency of several social-based routing approaches, such as Social-aware Content-based Opportunistic Routing Protocol (SCORP), dLife, dLifeComm, and Bubble Rap with their corresponding performance evaluations regarding the performance metrics: average remaining energy, delivery ratio, average delay, and transmission cost. Opportunistic Network Environment (ONE) simulator is used as the simulation tool, where all the simulations are performed by (i) varying the number of nodes in each group with a fixed message Time-To-Live (TTL), and (ii) changing the message TTL, while the number of nodes per group is kept constant. From the outcome of simulations, it is observed that SCORP has the highest energy efficiency and shows the best performances for average delay and transmission cost.

The Delay Tolerant Network (DTN) is a network architecture that plays an important role in intermittently connected networks. DTNs can support transmissions between clients even there are no end-to-end connections by using “store-carry-forward” mechanism, where some nodes called ferry nodes could be employed into DTN to enhance the network performance. In this paper, we use Unmanned Aerial Vehicles (UAVs) to act as ferry nodes, and a probabilistic routing protocol based on the encounter connection time between nodes is proposed. The proposed protocol not only considers the efficiency of message transmission but also the reliability between connected nodes. The proposed protocol and some existing protocols are compared and analyzed using ONE simulator. The simulation results show that the proposed protocol increases the delivery probability and reduces the average latency.

Near-real-time (nRT) ocean observations are critical for the sustainable management of coastal as well as offshore regions, including implementation of early warning systems, mitigation of pollution, response to extreme events and natural hazards. This can be achieved via the implementation of the so-called Ocean of Things, which consist of distributed networks of low-cost sensors enabling the acquisition of real-time or near-real-time data in support of the sustainable management of aquatic environments. In this project, we propose a LoRa-based system for sensor data collection at sea through mobile LoRa gateways mounted in ships. The sensor nodes will keep looking for mobile gateways, while trying to conserve energy, and will transmit their data as soon as a gateway ship approaches. The system aims at extending the LoRa network from the cities to the shore and finally to the open ocean.

The Coastal Patrol and Surveillance Application (CPSA) is developed and deployed to detect, track and monitor water vessel traffic using automated devices. Latest advancements of marine technologies, including the Automatic Underwater Vehicles, have allowed the development of this type of applications. To facilitate their operations, installation of a Coastal Patrol and Surveillance Network (CPSN) is mandatory. One of the primary design objectives of this network is to deliver adequate amount of data within an effective time period. This is particularly essential for reporting a detection and notifying the current status of an intruder’s vessel through the adverse underwater communication channels. Additionally, intermittent connectivity of the nodes remain another important obstacle to overcome to allow smooth functioning of CPSA. Taking these objectives and obstacles into account, this work proposes a new protocol, named UDTN-RS, which is developed by ensembling forward error correction technique (namely Reed-Solomon codes or RS) in Underwater Delay Tolerant Network (UDTN) routing protocol with probabilistic spraying technique. In addition, the existing binary packet spraying technique is enhanced for supporting encoded packet exchange between the contacting nodes. A comprehensive simulation campaign is performed in identifying the effectiveness of the proposed protocol. The obtained results suggest that the proposed UDTN-RS protocol can be considered a suitable alternative of the existing protocols for sparse networks like CPSN.

The probabilistic Delay Tolerant Network (DTN) routing has been adjusted for vehicular network (VANET) routing through numerous works exploiting the historic routing profile of nodes to forward bundles through better Store-Carry-and-Forward (SCF) relay nodes. In this paper, we propose a new hybrid swarm-inspired probabilistic Vehicular DTN (VDTN) router to optimize the next-SCF vehicle selection using the combination of two bio-metaheuristic techniques called the Firefly Algorithm (FA) and the Glowworm Swarm Optimization (GSO). The FA-based strategy exploits the stochastic intelligence of fireflies in moving toward better individuals, while the GSO-based strategy mimics the movement of glowworm towards better area for displacing and food foraging. Both FA and GSO are executed simultaneously on each node to track better SCF vehicles towards each bundle&rsquo, s destination. A geography-based recovery method is performed in case no better SCF vehicles are found using the hybrid FA&ndash, GSO approach. The proposed FA&ndash, GSO VDTN scheme is compared to ProPHET and GeoSpray routers. The simulation results indicated optimized bundles flooding levels and higher profitability of combined delivery delay and delivery probability.

As a new architecture, delay tolerant network (DTN) has been widely studied and applied in recent years. DTN protocol has its own store and forward mode, which makes it stand out in some restricted networks. Due to the fact that the aircraft cluster network works in a highly confrontational environment, the node position and global link state change constantly, which frequently triggers the process of route update or location update. It is very easy for the network partition or communication interruption to occur in the military battlefield. The traditional network protocol is difficult to apply. This paper discusses the feasibility of introducing DTN architecture into aircraft cluster network, in order to solve the problems such as intermittent connection of communication links and limited communication of different subnets, and to ensure the reliability and success rate of data transmission between aircrafts.

In the traditional communication process, the end-to-end transmission has certain path and the end-to-end round-trip time is not too long, but there exist dynamic weak networks in which the TCP/IP protocol stack is not applicable. To achieve data deliver, Delay Tolerant Network (DTN) can be used as an effective processing method. However, it’s more difficult to realize service broadcast which is one-to-many in such networks, so ensuring the reliability and continuity of DTN end-to-end service transmission for service broadcasting has become an important issue to be solved. This paper first analyzes the characteristics and application scenarios of DTN, and establishes optimization models in different scenarios with the goal to maximize service transmission throughput, and then apply Deep Q-learning Network (DQN) algorithm in these scenarios. Finally, it is found that when the link is interrupted, the algorithm can not only reduce the end-to-end delay of broadcasting but also guarantee the service delivery rate.

Delay tolerant networking (DTN) is proposed to deliver message successfully, even in an extreme environment, where network connectivity is not guaranteed. In this paper, we consider group mobility model and propose a novel protocol for group mobility in DTN. Simulation results show that the proposed protocol has better delivery ratio and overhead ratio than PRoPHET protocol.

This paper develops the concept of a cognitive network and describes a microservice based architecture which could be used to implement such a system. Delay tolerant networking (DTN) influences the design of the architecture as well as the networking scenarios that the system attempts to address. A cognitive storage and fragmentation service is developed based on existing artificial intelligence techniques such as Advantage Actor Critic (A2C) and Deep Q-Networks. The system is simulated using OpenAI Gym in a custom developed DTN environment.

Flying Adhoc Network (FANET) is an emerging topic of research in the wireless network area, FANET has several common features with its predecessor e.g. Mobile Adhoc Network (MANET) and Vehicle Adhoc Network (VANET), but the network has several unique features also which make it different from other networks. The sparseness of nodes, coupled with frequent changing of topology significantly affects the data transmission rate of the network. To overcome this problem, FANET can be assisted with Delay Tolerant Network (DTN) approach to exploit its mobility and routing features. The main aim of this work is to make Flying Adhoc Network reliable by deploying two MAC protocols i.e. IEEE 802.11 and IEEE 802.15 and realize the functionality of Delay Tolerant Network (DTN) in a FANET.

In rural areas an ambulance carrying a patient may require to connect with experts in a city. In rural areas it is not possible that network connectivity to the ambulance available all the time. In this type of situation concept of delay-tolerant networks may be utilized for the opportunistic connectivity with a person at distance. Delay-Tolerant Network (DTN) is an approach to a wireless network, which possesses an uncertainty in the connection. Due to intermittent connectivity and long delays, routing in DTN turns out to be quite challenging. In recent years, many social-based routing reflects the capabilities of social attributes for disseminating data. In this paper social attributes namely, community, similarity, betweenness, and degree centrality are being used for outlining a routing technique. Using this approach we can improve the quality of service provided by the ambulances while passing through rural areas. A comparison is made with already proposed routing technique, for example, BUBBLE Rap, Epidemic, and experiences a noteworthy improvement in delivery ratio and buffer utilization.

In this work, we focus on vehicular-based message delivery methods that are effective in disaster situations. In our previous work, we proposed a message relaying method with Enhanced Dynamic Timer (EDT) for Vehicular Delay Tolerant Networking (DTN). In this paper, we evaluate the network performance of proposed EDT considering different reset threshold for Vehicular DTN. From the simulation results, we found that setting of RT less than 0.5 reduced storage usage regardless the number of vehicles.

Smart city includes all kinds of advanced technologies and solutions, and its maintenance is achieved through massive data collection. In Delay Tolerant Network (DTN), sensors that lack connectivity can store data temporarily and wait for the mobile vehicles in the city to forward, which significantly improves the efficiency of data collection in the city. However, mobile vehicles are not always credible, since the attack from malicious vehicles may be detrimental to data quality. Therefore, there is an urgent need for a secure data collection strategy with mobile vehicles. In this paper, a consistency trust verification strategy for mobile vehicles (CTV-MV) is proposed, including three stages: opportunistic routing, recruitment, and trust verification. Specifically, an average-distance-based outlier detection (ADOD) algorithm is designed to verify heterogeneous data. Then a baseline mechanism is used to trust reasoning for evaluating the trust value. Furthermore, a recruitment strategy that considers trust and data coverage ratio is proposed to maximize data quality. Finally, the performance of CTV-MV is analyzed through experiments in terms of the excellent ratio of data and recruit cost, respectively.

In the recent years, the Delay Tolerant Networks (DTNs) have been increasingly researched, offering alternative solutions in real-life contexts where the Internet cannot be used. Even if most of the proposed routing algorithms do not provide a buffer management policy, it was later demonstrated that the implementation of such a policy can considerably improve the performance metrics of the network. This paper presents an intermediate phase of an algorithm that optimizes the message transfer rate and resource consumption in a DTN network, in the context of a natural disaster situation. The proposed algorithm is called MaxDelivery and it has a specific policy for buffer management implemented.

Although social media and contents are being generated and shared with an unprecedented scale and speed, rural and underdeveloped areas throughout the world have only limited access due to the lack of high-speed Internet. Connecting rural communities to the digital world and providing them with right contents will provide the much-needed bridge between urban and rural areas. In this paper, we propose a communication and information framework that utilizes simple Internet of Things (IoT) in a rural community to assist delay-tolerant content distribution. Specifically, a hybrid fog-cloud content distribution network is constructed by deploying low-end simple fog nodes and utilizing the movement of community vehicles. Moreover, drones are used to distribute content on demand as a compliment of the delay tolerant network for better delivery rate and lower delay time. A novel drone scheduling algorithm is proposed to plan drones’ tours optimally. Extensive simulation experiments have been performed to evaluate the performance of the proposed framework.

Delay tolerant network (DTN) is an approach that allows the transmission of data in a difficult situation where refined infrastructures are unavailable and the end-to-end path does not exist at the moment of transmission of data. The DTN efficiently improves network communications where the network connectivity is irregular or prone to disruptions. For transmission, DTN uses different kinds of routing protocols but still, they may lack some aspects such as buffer size, delivery rate, and number of message copy. In this paper, we represent an efficient routing protocol that is based on flooding and forwarding techniques along with the delivery predictability of nodes for transmission of messages. The main idea of the proposed model is to accelerate the dissemination of message in the early phase by employing spray and wait, and then to restrict dissemination in the later phase by using delivery predictability. We evaluated the performance of our protocol by simulation through the Opportunistic Network Environment (ONE) simulation tool. Obtained results show that ERP maintains a balance and offers a better way for the transmission of messages.

This paper aims to draw a parallel between the component elements of a queuing system and the buffer management used by the Delay Tolerant Network (DTN) nodes. Given that waiting in a queue is a widespread practice, many times it has been tried to optimize the time spent in such queues. The Introduction of the paper contains a briefly description for some elements of buffer management in DTN networks. The second section presents an initial information of queuing theory and several related works. The third section draws a parallel between buffer management in DTN and queuing systems by implementing a new drop policy as a part of buffer management. The obtained results will be illustrated with the help of a practical network context, using the ONE simulator.

In this paper, we propose a spatio-temporal data aggregation protocol in Vehicular Delay Tolerant Network (VDTN). We focus on Asynchronous Vehicular Crowdsensing Service (AVCS) to collect volume sensor data (e.g., images captured by on-board cameras) from VDTN-enabled vehicles. In AVCS, it is critical to cope with the huge redundant traffic generated by a large number of vehicles. We propose a novel protocol to aggregate volume spatio-temporal sensor data in Hybrid DTN data collection architecture. By assigning spatio-temporal identifiers (STI) to the aggregation targets in AVCS and extending the message exchange protocol to treat STI in VDTN, the redundant traffic can be significantly improved. Simulation results using a real taxi trace dataset showed the effectiveness of the proposed data aggregation protocol. The coverage of the crowdsensing was improved around 20-35% with 80% traffic reduction compared with the baseline aggregation protocol.

Delay Tolerant Networking (DTN) is characterized by its dynamic and intermittent connectivity, resulting in the absence of end-to-end communication paths in general. Many proposed solutions have been developed over the years to enhance TCP/IP protocol stack for DTN environment; Epidemic Routing (ER) is among the earliest and most well-known designs. Recent years have seen both renewed interests and investigations into Epidemic Routing for vehicular and satellite communications, and the development of a new Internet architecture Named Data Networking (NDN) which, due to its data-centric design, can support DTN communications natively. In this paper, we identify the basic functionality requirements for DTN support, compare and contrast ER and NDN to show the commonalities and differences in their designs. We use simulation results to illustrate how the design differences lead to different functionalities and protocol performance: although ER enhances IP nodes with data-centric features to enable packet delivery in DTN environments, compared to NDN's native data-centric design with built-in security, such “patch-on” suffers from not only lower performance with higher overhead, but more importantly the lack of systematic security support.

Mobility models are widely used for the evaluation of Delay Tolerant Networks (DTNs) performance, this mitigates the need for the model that can generate patterns that guarantee the contact opportunities for a reliable package forwarding. In this paper, we present a new mobility model that describes students’ daily activities in a campus environment. As opposed to the conventional models such as a Random walk, Random waypoint, Random direction, etc which uses a free space environment, our model includes obstacles of different shapes and sizes that obstruct movement and signal propagation. We evaluate the model using ONE simulator by comparing it with the Working Day Model and Random Waypoint. The model synthetically generates traces with the distribution of contact duration and inter-contact time similar to the distribution of real traces. We further investigate its impact on the performance of DTNs routing protocols and the result shows that, it performs better than the existing models in terms of average delivered message and message latency.

Unmanned aerial vehicles (UAVs) can gather data in the air and transmit the data to the ground station. Multi-UAV systems have been used in an increasing number of mission scenarios and routing protocols play a critical role in UAV network communications. It is now well established that unstable link quality and frequently changing network topology pose significant challenges for messages forwarding in UAV networks. Hence, traditional mobile ad-hoc network routing protocols do not fit well in UAV networks. In many UAV applications, the flight paths of UAVs are planned in advance before performing missions. The positions and motion information of UAVs are available through Global Positioning System (GPS) and inertial sensors, which can be utilized to calculate the future positions of UAVs. Therefore, the future topology of the UAV network is also available. However, existing work does not take advantage of this information. Based on the trajectory, location and motion information of the UAVs, this paper proposes a future network topology-aware routing (FNTAR) protocol, which uses future location information to make superior routing decisions. Moreover, to mitigate data loss problems caused by unstable links and highly dynamic topology, FNTAR can forward messages to multiple excellent next-hop UAVs based on future network topology, and these UAVs can deliver messages to destinations faster. We implement FNTAR in the simulation experiment, the simulation results demonstrate that FNTAR can achieve lower latency and higher delivery ratio than DTN geo protocol.

Delay tolerant networks (DTN) is a good candidate for delivering information-centric networking (ICN) messages in fragmented networks due to disaster. In order to efficiently deliver ICN messages in DTN, the characteristics of multiple requester nodes for the same content and multiple provider nodes for the same request should be used efficiently. In this paper, we propose an efficient DTN routing protocol for ICN. In the proposed protocol, requester information for request packet, which is called an Interest in ICN, is shared by exchanging status table with requested Data ID, requester ID, and satisfaction flag, where satisfaction flag is defined to show the delivery status of Data, so that unnecessary forwarding of Data is avoided. Data is forwarded to a more probable node by comparing average delivery predictability to a set of requesters. Performance of the proposed protocol was evaluated using simulation from the aspect of Data delivery probability and Data overhead, for varying buffer sizes, number of relay nodes, and time-to-live (TTL) of Data. The results show that the proposed protocol has better Data delivery probability, compared to content distribution and retrieval framework in disaster networks for public protection (CIDOR) and opportunistic forwarding (OF) protocols, although there is a tradeoff from the aspect of Data overhead for varying buffer sizes and number of relay nodes.

In search and rescue mission, micro aerial vehicles (MAVs) are typically used to capture image and video from an aerial perspective and transfer the data to the ground station. Because of the power limitation, a cluster of MAVs are required for a large search area, hence an ad-hoc wireless network must be maintained to transfer data more conveniently and fast. However, the unstable link and the intermittent connectivity between the MAVs caused by MAVs’ movement may challenge the packet forwarding. This paper proposes a delay tolerant packet forwarding algorithm based on location estimation for MAV networks, called DTNest algorithm. In the algorithm, ferrying MAVs are used to transmit data between MAVs and the ground station, and the locations of both searching MAVs and ferrying MAVs are estimated to compute the distances between the MAVs and destination. The MAV that is closest to the destination is selected greedy to forward packet. If a MAV cannot find the next hop MAV using the greedy strategy, the packets will be stored and re-forwarded once again in the next time slot. The experiment results show that the proposed DTNest algorithm outperforms the typical DTNgeo algorithm in terms of packet delivery ratio and average routing hops.

The concept of SDN enables revolutionary automation and policy based management in the era of networking. In these phenomena, there is no vendor's specification to implement the new features over the network system. Delay-tolerant networking (DTN) is a type of wireless ad-hoc network. It works when the end to end direct path does not exist between source and destination then it's using the Store and Forwarding routing mechanism. This research study will propose a new architecture with the combination of SDN (Software Defined Networking) and DTN (Delay Tolerant Network) which has four layers Victim node, DTN Layer, DTN Tend and Control station. Victim nodes are simple DTN enables devices such as PDA, smartphone. DTN layer is the combination of bundle storage and convergence layer. DTN Tend is a monitoring application where it will monitor the whole network and give feedback to the controller so that the controller can decide for better performance. For the simulation of this proposed model was evaluated by using Mininet-WiFi. According to the simulation result on the best case scenario the message delivery rate is 99.540% and packet loss is 0.460%. Though this proposed architecture has few limitations such as no priority has been set between defined services, if all defined service requests come at a time then it will be FCFS based.

For complex missions that are away from Earth's resources, there is an unmet need for more autonomous operations with minimal Earth contact. This paper describes taraCoAP, an adaptation of the terrestrial IETF standard Constrained Application Protocol (CoAP) over the Bundle Protocol. taraCoAP, with its innovative Cyber-Physical Autonomous Asset Observation and Management extension, provides an efficient and secure RESTful delay and disruption tolerant communication framework. taraCoAP, currently at TRL-6, has been successfully tested with Jet Propulsion Lab's latest Interplanetary Overlay Network (ION) delay tolerant networking (DTN) solution. The paper also describes Antara's Deep Space Autonomous Exploration DTN Simulator that utilizes taraCoAP Services to initiate and observe autonomous operations in deep space. Additionally, a case study in a relevant environment is presented where a cluster of satellites autonomously collaborate to form a large telescope aperture in deep space. The successful deployment of missions utilizing taraCoAP Services will enable various types of space vehicles to securely and efficiently communicate with other space vehicles independently and make possible entirely new classes of missions.