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.

Non-dominated Sorting Genetic Algorithm-II for Throwbox Deployment in Delay Tolerant Networks

Delay-tolerant networks (DTNs) are basically opportunistic networks and uses store-carry-and-forward switching for message forwarding. Performance of DTNs can be improved by placing stationary nodes, called throwboxes which increases the contact opportunities among nodes. Throwbox is viewed as relaying node and the message delivery is enhanced by spreading as many messages as possible. Increasing the contact opportunities in throwbox based DTN model depends on the deployment of throwboxes in suitable places. The objective of this paper is to identify optimal deployment locations of the throwboxes with a pre-specified transmission range, and to maximize the coverage of all the throwboxes in order to increase average delivery and to reduce the average delay among all the nodes in the network. We use Non-Dominated Sorting Genetic Algorithm–II for optimizing the deployment of throwboxes in DTN. The simulation results are analyzed for better strategy in deploying throwboxes and to improve the performance of throwbox-augmented DTNs.

A Novel Routing Scheme for Creating Opportunistic Context-Virtual Networks in IoT Scenarios

The massive amount of traffic required by the emerging Internet of Things (IoT) paradigm can be supported by the imminent arrival of 5G next-generation networks. However, the limited capacity of resources in IoT nodes, e.g., battery lifetime or buffer space, opens a challenge to be taken into account when proposing new routing solutions on IoT scenarios with intermittent connectivity. In this paper, we propose the concept of Opportunistic Context-Virtual Networks (OCVNs). The novelty of this approach is to create virtual groups of nodes that share interests in common for routing purposes. Therefore, only the nodes that are interested in the content of the messages that are flowing throughout the network are used as relaying nodes, providing their own resources for the sake of the communication. By leveraging the use of store-carry-and-forward mechanisms, a novel routing algorithm is proposed and evaluated over two realistic scenarios. Experimental results reveal that our solution outperforms other well-known opportunistic routing algorithms in terms of delivery probability and overhead ratio, while resource usage of relaying nodes is significantly reduced.

Reliable and Efficient Routing Mechanisms for Vehicular ad-hoc Network

In order to provide stable connections among nodes, a routing protocol is necessary in VANET system. Dynamic topology and frequent disconnection makes difficult to design an efficient routing protocol for VANET to route information among nodes. The survey of routing protocols in VANET system helps in understanding the concepts of smart intelligent transport system (ITS). It is observed that carry-and-forward is the key consideration and main function of an efficient routing protocol in VANET system. This paper explains various routing protocols for VANET system.

Analysis of Supply Chain Wastage for Banana at Wholesale Distribution Points in Tamilnadu

India is the second largest producer of overall fruits and vegetables next to China as on 2015. In spite of being a major producer of fruits, various studies were reported that nearly from 20 to 75% of fruits are wasted in India due to various reasons. Fruits wastage was realizing in all stages of its supply chain from farm gate to till it reaches to the consumer. This study concentrates only one supply chain stage i.e. wholesale distribution points in Tamilnadu. This study was conducted based on descriptive research. Scope of this study was confined within Tamilnadu region with 13 specific locations. Data were collected from banana middlemen wholesale traders which include distributors, wholesale agents, commission agents, mandi agents, carry and forward agents, contractors and brokers. Data were collected from 154 wholesale traders through interview as well as survey method by using structured questionnaire. This study revealed that around 6.5% of bananas were getting wasted at wholesale level. This study also identified top three factors which influenced more wastage at wholesale distribution points of banana, they were physical injury, long travel and poor packing method.

Assessing Contact Graph Routing Performance and Reliability in Distributed Satellite Constellations

Existing Internet protocols assume persistent end-to-end connectivity, which cannot be guaranteed in disruptive and high-latency space environments. To operate over these challenging networks, a store-carry-and-forward communication architecture called Delay/Disruption Tolerant Networking (DTN) has been proposed. This work provides the first examination of the performance and robustness of Contact Graph Routing (CGR) algorithm, the state-of-the-art routing scheme for space-based DTNs. To this end, after a thorough description of CGR, two appealing satellite constellations are proposed and evaluated by means of simulations. Indeed, the DtnSim simulator is introduced as another relevant contribution of this work. Results enabled the authors to identify existing CGR weaknesses and enhancement opportunities.