Exploring an energy-efficient DTN framework supporting disaster management services in post disaster relief operation

Generic prediction assisted single-copy routing in underwater delay tolerant sensor networks

Majority of the existing Delay Tolerant Network (DTN) routing protocols, attempt to minimize one of the popular DTN routing indices, i.e. message delay, forwarding count and storage. However, for many DTN applications such as distributing commercial content, targeting the best performance for one index and compromising the others is insufficient. A more practical solution would be to strike a balance between multiple of these indices. Gain Dissemination Protocol (GDP) is one of the protocols which targets this aim by introducing a gain concept which tries reach a maximum gain of delivery by keeping the balance between the value achieved via delivering the packet to the destination and the forwarding cost involved with that. In this paper, we focus on characterizing the GDP protocol in the scope of mobility. We also propose an upper bound for gain in multicast routing problem, i.e. the Union of Unicast Benchmark (UUB) and compare the performance of a few DTN routing protocols with the former. This eventually reveals the performance scope of a potential gain-aware DTN dissemination protocol.

In delay tolerant networks (DTNs), nodes have intermittent connectivity patterns due to various factors such as mobility, sparse network topology, and unpredictable movement patterns. In such networks, nodes store messages, carry them along as they move and forward them opportunistically whenever an encounter occurs. In many DTN applications, such as in disaster situations and remote regions with no communications infrastructure, we can envisage a network topology formed by the mobility and contact pattern of people carrying their mobile devices. The social behavior of people (nodes) in Spatio-temporal dimensions governs the formation of such a topology. To improve data dissemination in such networks, several works have proposed to utilize social-aware metrics for the selection of relays. However, existing routing protocols for DTNs may perform poorly in the scenarios in which nodes are localized in multiple small regions, and the topology is sparse such as in co-located villages in remote regions with no communication infrastructure. This work proposes a Cooperative mobile throwbox-based routing protocol (CMTR) for social-aware DTNs. In CMTR, static and mobile ThrowBoxes (TBs) are deployed to improve the efficiency of a DTN. The static and mobile TBs cooperatively relay data to enhance network efficiency. Performance evaluation via simulations in ONE simulator shows that CMTR improves the data delivery ratio, delays, and energy efficiency as compared to Epidemic routing and Bubble Rap routing schemes.

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.

A survey of routing and data dissemination in Delay Tolerant Networks

Delay-Tolerant Networks (DTN) are intermittent wireless mobile networks designed to handle communications in environments where network connectivity is often disrupted due to node mobility or the absence of fixed infrastructures.These frequent disconnections lead to repeated communication attempts between nodes, thereby increasing energy consumption.DTN is often deployed in isolated and hard-to-reach environments with limited energy sources, imposing significant constraints on the performance and operational lifetime of individual DTN nodes, as well as the DTN network as a whole.Despite the significant efforts invested by researchers to develop energy-efficient algorithms and models, the problem of energy consumption persists, especially with nonrenewable sources.The motivation for this research is based on the major challenges related to powering mobile nodes in DTN networks, notably due to the absence of reliable and constant energy sources.The energy constraints of the nodes, combined with their mobility, raise problems of energy consumption and durability, leading to communication interruptions, delays, data losses, and a decrease in the overall efficiency of the network.To overcome these challenges, the article proposes a long-term energy management strategy by integrating renewable energy sources, notably solar energy, into the architecture of DTN nodes.The contributions include the modeling of an energyautonomous and sustainable solar-powered DTN node, the evaluation of the energy generated and stored by these nodes, and the validation of the effectiveness of this approach through simulations in the ONE simulator, considering realistic mobility scenarios and communication conditions.The results show that solar DTN nodes have significantly higher residual energy than those with limited power sources.Additionally, social mobility models (MBM, SPMBM) consume more energy than individual models (RW, RWP, RD), while the Spray-and-Wait and PROPHET protocols are more energy-efficient compared to Epidemic and MaxProp.These analyses reveal optimal combinations of DTN protocols and mobility models to reduce energy consumption: the Spray-and-Wait protocol aligns well with social mobility models, while PROPHET is more suited to individual mobility models.

The Delay Tolerant Networks (DTNs), are emerging as one of the most efficient network that allow nodes in intermittently connected networks to communicate with each other. They are designed to overcome high latency and lack in connectivity due to poor infrastructure and short range radios. However, the DTNs relay nodes have limited resources (i.e., low-power RF module, low computation capacity, limited buffer size, short battery power). Moreover, the DTNs routing protocols, which route the message between a source and a target destination, are very numerous, including the famous Epidemic routing, k-hop routing, prophet routing. Consequently, We found that it would be valuable to compare these prominent opportunistic networks protocols under constraint of energy consumption in forwarding activity. We have done this using the ONE simulator and evaluated the schemes with regard to message delivery probability, energy efficiency.

In a Delay Tolerant Network (DTN), the nodes have intermittent connectivity and complete path(s) between the source and destination may not exist. The communication takes place opportunistically when any two nodes enter the effective range. One of the major challenges in DTNs is message forwarding when a sender must select a best neighbor that has the highest probability of forwarding the message to the actual destination. However, finding an appropriate route remains an NP-hard problem. This paper presents a concept of Checkpoint (CP) based message forwarding in DTNs. The CPs are autonomous high-end wireless devices with large buffer storage and are responsible for temporarily storing the messages to be forwarded. The CPs are deployed at various places within the city parameter that are covered by bus routes and where human meeting frequencies are higher. For the simulative analysis a synthetic human mobility model in ONE simulator is constructed for the city of Fargo, ND, USA. The model is tested over various DTN routing protocols and the results indicate that using CP overlay over the existing DTN architecture significantly decreases message delivery time as well as buffer usage.

A Delay Tolerant Network (DTN) is a network capable of handling long delays and data loss efficiently in various challenged scenarios and environments. Owing to the mentioned challenges, it becomes crucial to study how the routing protocols are designed to adapt in such networks. Currently, the research in this domain is focused on the improving the data delivery ratio and minimizing delays in the routing protocols. This paper reviews state-of-the-art routing protocols for Delay Tolerant Networks (DTNs) as well as performs their comparative analysis. DTN routing protocols are grouped into four categories viz encounter based, time based, infrastructure based and hybrid & others. This categorization depends on the information they use for relay selection routing. We have also discussed some of the inherent drawbacks such as energy consumption, delivery rates and buffer constraints of the existing routing algorithms. We have also conducted an empirical analysis and observed the performance of the most popular existing algorithms of encounter and time based category. This paper offers a widespread study of the routing protocols with their pros and cons.

There is a growing need for secure and robust networks that function in austere environments or with nodes that have limited resources. The prime example is Delay Tolerant Networks that have military, first response, infrastructure failure and vehicle applications. This class of networks requires the modification of traditional routing and security protocols, such as TCP/IP or the use of certificate revocation servers, to effectively transmit a message from source to destination in a secure manner. There are multiple trust and routing schemes proposed for use in Delay Tolerant Networks. Here, we show how trust, usually defined in the context of network science, can be utilized for routing in Delay Tolerant Networks in which the fundamental challenge is balancing energy, delivery rate, delivery delay and security. Trust is a cornerstone of our approach to address this challenge. We propose a Trust Based Secure Routing Protocol, in which forwarding decisions are based on nodes trust, expected destination meeting time and the number of already created copies of the message.

Information-Centric Networking (ICN) is a prominent topic in current networking research. ICN design significantly considers the increased demand of scalable and efficient content distribution for Future Internet. However, intermittently connected mobile environments or disruptive networks present a significant challenge to ICN deployment. In this context, delay tolerant networking (DTN) architecture is an initiative that effectively deals with network disruptions. Among all ICN proposals, Content Centric Networking (CCN) is gaining more and more interest for its architectural design, but still has the limitation in highly disruptive environment. In this paper, we design a protocol stack referred as CCNDTN which integrates DTN architecture in the native CCN to deal with network disruption. We also present the implementation details of the proposed CCNDTN. We extend CCN routing strategies by integrating Bundle protocol of DTN architecture. The integration of CCN and DTN enriches the connectivity options of CCN architecture in fragmented networks. Furthermore, CCNDTN can be beneficial through the simultaneous use of all available connectivities and opportunistic networking of DTN for the dissemination of larger data items. This paper also highlights the potential use cases of CCNDTN architecture and crucial questions about integrating CCN and DTN.

In challenged networks, such as opportunistic networks or Delay Tolerant Networks (DTNs), due to frequent network partition an end-to-end connection between source and destination may not always be possible due to nodes move unpredictably with high speeds. For such type of networks, traditional routing protocols fails to transmit and also no guarantee on delivery of data to specified destination because these protocols deliver data definitely whenever there exists continuous end-to-end connectivity between source and destination over time. To provide efficient routing for such networks replication based routing schemes were proposed to achieve higher delivery probability. Unlike Internet protocols, Delay Tolerant Networks routing protocols follow store-carryforward mechanism to reduce packets dropping probability, tolerate delays and improve delivery performance in terms of delivery ratio and delivery latency. This paper defines the most efficient replication based routing protocols such as epidemic, PROPHET, spray and wait and Encounter based routing. This paper also explains how message TTL, buffer sizes and area of grid impact performance of replication based routing protocol in terms of delivery ratio and Average latency and overhead ratio.

Nowadays, the research and application about delay-tolerant network (DTN) have become more and more popular. A communications network that is capable of storing packets temporarily in intermediate nodes, until the time an end-to-end route is reestablished or regenerated is known as a delay tolerant network/s, in short, DTN.Routing of the packets in DTN is based on store-carry-and forward paradigm. When a node receives a message but no availability of paths towards destination node, the message should be buffered in the current node and wait for opportunities to encounter other nodes. This paper aims to detail basic & general aspects specific to information needs in DTN routing and present classification chart. We discuss some detail of routing issues and classifications of routing protocols. Routing is one of the major issues affecting the overall performance of DTN networks in terms of resource consumption, data delivery. Over the past few years a number of routing protocols have been proposed for DTN networks. In this paper mainly three DTN routing protocols Epidemic, PROPHET and Spray and Wait Routing protocols are discussed.

Delay tolerant network (DTN) routing provides a communication primitive in intermittently disconnected networks, such as battlefield communications and human-contact networks. In these applications, the anonymity preserving mechanism, which hides the identities of communicating parties, plays an important role as a defense against cyber and physical attacks. While anonymous routing protocols for DTNs have been proposed in the past, to the best of our knowledge, there is no work that emphasizes analysis of the performance of these protocols. In this paper, we first design an abstract of anonymous routing protocols for DTNs and augment the existing solution with multi-copy message forwarding. Then, we construct simplified mathematical models, which can be used to understand the fundamental performance and security guarantees of onion-based anonymous routing in DTNs. To be specific, the delivery rate, message forwarding cost, traceable rate, and path and node anonymity are defined and analyzed. The numerical and simulation results using randomly generated contact graphs and the real traces demonstrate that our models provide very close approximations to the performance of the anonymous DTN routing protocol.

Delay Tolerant Network (DTN) is a sparse and intermittently connected mobile wireless network where reliable communication and end-to-end connectivity cannot be assured. In DTN, a node delivers messages to the destination using store and forward scheme. Messages are copied and transferred to multiple relay-nodes in order to increase the opportunity for that message to reach the intended destination. Contact is the time duration for which two or more mobile nodes encounter each other within their radio transmission ranges, and are able to transfer messages. Due to arbitrary node movement, contact time will be varied, and is unlikely to be predictable. In this paper, we propose a fuzzy decision mechanism we called “fuzzy-spray”, to improve the routing and packet transfer efficiency in DTN environment. Fuzzy-spray can reduce overall latency in DTN by intelligently selecting appropriate messages to send to the relay-node during its next contact time. It uses fuzzy logic to prioritize messages that are stored in the buffer, based only on local parameters from each message, namely forward transmission count and message size. There is no need to know a priori information about network such as node mobility model, or node-distribution across the deployed area. The simulation results show that fuzzy-spray has the best performance in terms of overall speed of delivery, and lowest average message delay compared with other existing algorithms.