Performance Analysis of Delay Tolerant Network Routing Protocols in a Heterogeneous Vehicular Network

Intermittently Connected Mobile Networks (ICMNs) are sparse wireless networks where most of the time an end-to-end path does not exist from source to destination. These networks are characterized by opportunistic connectivity, long and variable delay, asymmetric data rate and high error rate. Hence, they can be appropriately modeled as Delay-Tolerant Networks (DTNs). In this paper, the performance of replication-based DTN routing protocols, namely Epidemic, PRoPHET, MaxProp, RAPID, Binary Spray-and-Wait, and Spray-and-Focus has been investigated in an ICMN scenario against varying message generation rates and number of mobile nodes, respectively. The performance is analyzed on the basis of three metrics: Delivery Probability, Average Latency, and Overhead Ratio. Opportunistic Network Environment (ONE) simulator is used as the simulation tool for evaluating these performance metrics. The outcome of this work shows that for the ICMN scenario and given simulation setting, the best DTN routing technique is Spray-and-Focus, whereas Epidemic routing exhibits the worst performance in terms of all the metrics considered here.

Today’s network becomes more complex due to which performances of network decrease like message delivery ratio, overhead ratio, average latency, cost, etc. A new technique comes to forward the message on the basis of social infrastructure. In this paper, we analyze and compare the result of social-based opportunistic routing protocol with different mobility traces, and we compare the BubbleRap, DLife (daily life routine routing algorithm) and dLifeComm (daily life routine community-based routing algorithm) social routing protocol with different movement models and real traces with respect to delivery ratio, overhead ratio, and average latency. Comparison is based on the real human traces and synthetic mobility model. We use Opportunistic Network Environment (ONE) simulator for result analysis. As from the simulation result, delivery ratio of BubbleRap is better than DLife and dLifeComm when node follows the community-based movement.

In this paper, we evaluate and compare the performance of single-copy and multiple-copy routing protocols in a realistic Vehicular Delay Tolerant Network (VDTN) scenario. The simulations are conducted with the Opportunistic Network Environment (ONE) simulator. The performance is analyzed using delivery probability, overhead ratio, average latency, average number of hops and average buffer time metrics. The simulation results show that multiple-copy protocols perform better in terms of delivery probability compared with singlecopy protocol. The single-copy protocol uses the highest average number of hops and higher average latency compared with multiple-copy protocols. Maxprop achieves the highest delivery ratio and lowest average latency. Spray and wait results are the lowest for overhead ratio, but the longest for average buffer time. First contact have a short buffer time, but it uses a big number of hops.

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.

Networks that lack continuous connectivity among their nodes due to node mobility, limited data storage space and constrained power sources are called Delay Tolerant Networks (DTNs). DTN nodes store and carry the data packets until they come into the communication range of each other. In recent years several protocols have been developed specifically for routing in DTNs. These protocols vary in number of copies they use and the kind and amount of knowledge they use to guide the packets to their destinations. Remaining energy level, average latency, overhead ratio and delivery ratio are some of the performance metrics used to measure the performance of these protocols. The existing protocols are good in some of these metrics but not all of them. There is always a trade-off between different performance metrics. In this paper we have proposed a Hybrid protocol utilizing advantages of two protocols namely Epidemic and Probabilistic Routing. The performance is discussed and compared of these protocols with our Hybrid strategy in Opportunistic Network Environment tool.

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.

Delay-Tolerant Networks (DTNs) are kinds of networks where there does not exist any complete end-to-end route from source to destination. Such networks can also be referred to as Intermittently Connected Mobile Networks (ICMNs), which are featured by asymmetric data rates, large delay, limited resources and high error rates. In this network, size of buffer and Time-to-Live (TTL) for fixed number of nodes and message generation rates contribute to the network performance because of limited resources and short life span of a packet in the net-work. Therefore, investigating efficient routing for altering TTL and size of buffer is very important for overall network performance. This paper presents a performance analysis based on simulation of the impact of buffer size and TTL for several DTN routing protocols in ICMNs scenario. ONE, i.e., Opportunistic Network Environment is used to simulate the routing protocols considering three performance metrics: delivery ratio, mean latency and overhead ratio. Investigated results mention that Spray-and-Focus (SNF) routing exhibits the best performance for altering TTL and size of buffer than other DTN routing protocols, i.e., Epidemic, PRoPHET, PRoPHETv2, MaxProp, RAPID, and Binary-SNW in the considered performance metrics and simulation scenario.

PurposeIn this study, we discuss three DTN routing protocols, these are epidemic, PRoPHET and spray and wait routing protocols. A special simulator will be used; that is opportunistic network environment (ONE) to create a network environment. Spray and wait has highest delivery rate and low latency in most of the cases. Hence, spray and wait have better performance than others. This analysis of the performance of DTN protocols helps the researcher to learn better of these protocols in the different environment.Design/methodology/approachDelay-Tolerant Network (DTN) is a network designed to operate effectively over extreme distances, such as those encountered in space communications or on an interplanetary scale. In such an environment, nodes are occasional communication and are available among hubs, and determinations of the next node communications are not confirmed. In such network environment, the packet can be transferred by searching current efficient route available for a particular node. Due to the uncertainty of packet transfer route, DTN is affected by a variety of factors such as packet size, communication cost, node activity, etc.FindingsSpray and wait have highest delivery rate and low latency in most of the cases. Hence, spray and wait have better performance than others.Originality/valueThe primary goal of the paper is to extend these works in an attempt to offer a better understanding of the behavior of different DTN routing protocols with delivery probability, latency and overhead ratio that depend on various amounts of network parameters such as buffer size, number of nodes, movement ratio, time to live, movement range, transmission range and message generation rate. In this study, we discuss three DTN routing protocols: these are epidemic, PRoPHET and spray and wait routing protocols. A special simulator will be used; that is opportunistic network environment (ONE) to create a network environment. Spray and wait have highest delivery rate and low latency in most of the cases. Hence, spray and wait have better performance than others. This analysis of the performance of DTN protocols helps the researcher to learn better of these protocols in the different environment.

In intermittently connected delay tolerant wireless sensor networks, sensor data generated at sensor nodes should be delivered to a sink node using opportunistic contacts between intermittently connected nodes. Since there is no stable end-to-end routing path from a source node to a sink node in intermittently connected network, an opportunistic routing protocol to deliver sensor data efficiently is needed. In this paper, an improved opportunistic routing protocol is proposed, where both current delivery predictability and maximum delivery predictability are used together to decide whether sensor data should be forwarded or not to a contact node. The proposed protocol can reduce buffer overflow and thus increase the delivery ratio, which is one of the most important performance measures in delay tolerant wireless sensor networks. The performance of the proposed routing protocol is compared with that of PRoPHET protocol and FREAK protocol, by varying buffer sizes and the number of nodes, in terms of delivery ratio, overhead ratio, and delivery latency. Performance analysis results show that the proposed protocol has better delivery ratio, overhead ratio, and delivery latency than the PRoPHET protocol and FREAK protocol have, in most considered parameter values, with appropriate selection of message dissemination thresholds.

The Opportunistic Networking Environment (ONE) Simulator is an extensible tool for evaluating protocols and mobility models for delay-tolerant networking. ONE allows easily plugging in mobility models, contact traces, routing modules, applications, and report modules. In this paper, we describe how to instrument the ONE simulator for two content sharing applications: spreading content in waves across mostly stationary nodes and geo-based content sharing between mobile nodes using Floating Content. Both are included in the ONE simulator version 1.5.1.

Enhanced UAV-aided vehicular delay tolerant network (VDTN) routing for urban environment using a bio-inspired approach

The transition from analog to digital television has availed new spectrum called white space, which can be used to boost the capacity of wireless networks on an opportunistic basis. One sector in which there is a need to use white space frequencies is the healthcare sector because of existent protocols which are using it and the white space frequency is not as crowded as Wi-Fi. However, design simulations of wireless communication networks in white space frequencies have revealed dense network topology because of better signal propagation and penetration properties of white space frequencies. Consequently, communication networks designed in white space frequencies will require topology reduction for better communication and routing. Therefore, this paper proposes a link-based topology reduction algorithm to reduce a dense mesh network topology designed in white space frequencies into a sparse mesh network topology. The paper also proposes a network optimization function to introduce a hierarchical backbone-based network topology from the sparse network topology for better scalability. Performance evaluation on the proposed designs show that the designs can guide network engineers to select the most relevant performance metrics during a network feasibility study in white space frequencies, aimed at guiding the implementation process.

Sparse Deep Neural Networks (DNN) offer a large improvement in model storage requirements, execution latency and execution throughput. DNN pruning is contingent on knowing model weights, so networks can be pruned only after training. A priori sparse neural networks have been proposed as a way to extend sparsity benefits to the training process as well. Selecting a topology a priori is also beneficial for hardware accelerator specialization, lowering power, chip area, and latency.We present NeuroFabric, a hardware-ML model co-design approach that jointly optimizes a sparse neural network topology and a hardware accelerator configuration. NeuroFabric replaces dense DNN layers with cascades of sparse layers with a specific topology. We present an efficient and data-agnostic method for sparse network topology optimization, and show that parallel butterfly networks with skip connections achieve the best accuracy independent of sparsity or depth. We also present a multi-objective optimization framework that finds a Pareto frontier of hardware-ML model configurations over six objectives: accuracy, parameter count, throughput, latency, power, and hardware area.

Compared with the traditional Internet architecture, Delay/Disruption Tolerant Networking (DTN) has a bundle layer between the application layer and transport layer and is able to tolerate delays and disruptions. In this paper, we simulate typical DTN routing protocols and configure a vehicular network environment to evaluate the protocol performance. We compare the performance evaluation indicators that include delivery ratio, overhead ratio, average delay, and average buffer time with different node numbers and buffer sizes. We finish the simulation using Opportunistic Network Environment (ONE) simulator and the DTN routing protocols are evaluated according to the simulation results.

In this paper, we present a forwarding algorithm for mobile social opportunistic networks which is both centrality-based and energy-aware. In opportunistic networks, the nodes usually exploit a contact opportunity to perform hop-by-hop routing, since an end-to-end path between the source node and destination node may not exist. Centrality-based forwarding schemes use the structurally important nodes (i.e. nodes having many contacts with neighbors) as message relays and have been shown to be good candidates for social forwarding in opportunistic network environments. However, the most central nodes which are structurally more important than other network nodes, have the disadvantage to be used very frequently as message relays, thus consuming their energy very quickly. Here, we exploit the advantage of using a centrality-based scheme which is distributed and needs only the history of contacts as social information. In addition, we modulate the computed node centrality value using the node energy level in order to avoid transmissions in nodes more central but with a limited energy budget. Simulating three real-world mobility traces, we show that our scheme is able to achieve better delivery ratio and overhead ratio while sensibly reducing the energy consumption of nodes.