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In multi-radio wireless mesh networks, one node is eligible to transmit packets over multiple channels to different destination nodes simultaneously. This feature of multi-radio wireless mesh network makes high throughput for the network and increase the chance for multi path routing. This is because the multiple channel availability for transmission decreases the probability of the most elegant problem called as interference problem which is either of interflow and intraflow type. For avoiding the problem like interference and maintaining the constant network performance or increasing the performance the WMN need to consider the packet aggregation and packet forwarding. Packet aggregation is process of collecting several packets ready for transmission and sending them to the intended recipient through the channel, while the packet forwarding holds the hop-by-hop routing. But choosing the correct path among different available multiple paths is most the important factor in the both case for a routing algorithm. Hence the most challenging factor is to determine a forwarding strategy which will provide the schedule for each node for transmission within the channel. In this research work we have tried to implement two forwarding strategies for the multi path multi radio WMN as the approximate solution for the above said problem. We have implemented Global State Routing (GSR) which will consider the packet forwarding concept and Aggregation Aware Layer 2 Routing (AAL2R) which considers the both concept i.e. both packet forwarding and packet aggregation. After the successful implementation the network performance has been measured by means of simulation study.

Segment Routing (SR) leverages source routing. A node steers a packet through a controlled set of instructions, called segments, by prepending the packet with an SR header. A segment can represent any instruction topological or service-based. SR allows to enforce a flow through any topological path while maintaining per-flow state only at the ingress node of the SR domain. The Segment Routing architecture can be directly applied to the MPLS dataplane with no change on the forwarding plane. It requires a minor extension to the existing link- state routing protocols. This document illustrates the application of Segment Routing to solve the BGP Egress Peer Engineering (BGP-EPE) requirement. The SR-based BGP-EPE solution allows a centralized (Software Defined Network, SDN) controller to program any egress peer policy at ingress border routers or at hosts within the domain.

Delay Tolerant Networks (DTNs) have attracted much research interest recently due to its adaptability in areas without infrastructures. In such scenarios, moving data from one place (landmark) to another place (landmark) is essential for data communication between different areas. However, current DTN routing algorithms either fail to fully utilize node mobility or have additional requirements that cannot be satisfied easily in DTNs. Therefore, in this paper, we propose a distributed greedy routing algorithm, namely GreedyFlow, for efficient packet routing between landmarks in DTNs. GreedyFlow builds a local traffic map and a global landmark map on each node. The local traffic map indicates the node’s knowledge about the amount of traffic (node transition) between landmarks in the area where it primarily visits. The global landmark map shows the distribution of landmarks in the system and is built offline. In packet routing, the global landmark map shows the general packet forwarding direction, while the local traffic map helps determine the next-hop landmark on the fastest path in the forwarding direction. As a result, packets are greedily forwarded toward their destination landmarks. We also propose advanced components to enhance the consistency of local traffic maps and exploit node-based forwarding, both of which help improve the packet routing efficiency. Extensive real trace driven experiments demonstrate the high efficiency of GreedyFlow.

This document defines a YANG data model ([RFC6020], [RFC7950]) for segment routing ([RFC8402]) configuration and operation. This YANG model is intended to be used on network elements to configure or operate segment routing. This document defines also generic containers that SHOULD be reused by IGP protocol modules to support segment routing.

Segment Routing can be applied to the IPv6 data plane using a new type of Routing Extension Header. This document describes the Segment Routing Extension Header and how it is used by Segment Routing capable nodes.

Segment Routing (SR) allows for a flexible definition of end-to-end paths within IGP topologies by encoding paths as sequences of topological sub-paths, called "segments". These segments are advertised by the link-state routing protocols (IS-IS and OSPF). This draft describes the necessary IS-IS extensions that need to be introduced for Segment Routing operating on an MPLS data-plane.

Segment Routing (SR) leverages the source routing paradigm. A node steers a packet through a controlled set of instructions, called segments, by prepending the packet with an SR header. In the MPLS dataplane, the SR header is instantiated through a label stack. This document specifies the forwarding behavior to allow instantiating SR over the MPLS dataplane.

We study single commodity network flows with suitable robustness and efficiency specs. An original use of a maximum entropy problem for distributions on the paths of the graph turns this problem into a steering problem for Markov chains with prescribed initial and final marginals. From a computational standpoint, viewing scheduling this way is especially attractive in light of the existence of an iterative algorithm to compute the solution. This paper builds on the work proposed by Y. Chen et al. , [“Robust transport over networks,” IEEE Transactions on Automatic Control , vol. 62, no. 9, pp. 4675–4682, Sep. 2017] by introducing an index of efficiency of a transportation plan and points, accordingly, to efficient robust transport policies. In developing the theory, we establish two new invariance properties of the solution (called bridge )—an iterated bridge invariance property and the invariance of the most probable paths . These properties, which were tangentially mentioned in our previous work, are fully developed here. We also show that the distribution on paths of the optimal transport policy, which depends on a “ temperature ” parameter, tends to the solution of the “most economical” but possibly less robust optimal mass transport problem as the temperature goes to zero. The relevance of all of these properties for transport over networks is illustrated in an example.

Prior solutions for routing to multi-instantiated destinations simply adapt existing routing algorithms designed for single-instance destinations, or rely on flooding techniques. In this paper, a new approach for routing to multi-instantiated destinations is introduced, and the Multiple Instance Destination Routing (MIDR) framework is presented as an example of the approach. MIDR uses only distance information to multi-instantiated destinations, without routers having to establish overlays, know the network topology, use complete paths to destination instances, or know about all the instances of destinations. MIDR can be used in name-based content routing, IP unicast routing, multicasting, and anycasting; even in scenarios where the network topology is highly dynamic such as in the case of MANETs. It is shown that MIDR provides multiple loop-free paths to destination instances. Extensive simulation-based experiments performed in the context of MANETs show that MIDR outperforms traditional approaches based on unicast protocols and that it scales to large networks.

Geographic routing has been considered as an attractive approach for resource-constrained wireless sensor networks (WSNs) since it exploits local location information instead of global topology information to route data. However, this routing approach often suffers from the routing hole (i.e., an area free of nodes in the direction closer to destination) in various environments such as buildings and obstacles during data delivery, resulting in route failure. Currently, existing geographic routing protocols tend to walk along only one side of the routing holes to recover the route, thus achieving suboptimal network performance such as longer delivery delay and lower delivery ratio. Furthermore, these protocols cannot guarantee that all packets are delivered in an energy-efficient manner once encountering routing holes. In this paper, we focus on addressing these issues and propose an energy-aware dual-path geographic routing (EDGR) protocol for better route recovery from routing holes. EDGR adaptively utilizes the location information, residual energy, and the characteristics of energy consumption to make routing decisions, and dynamically exploits two node-disjoint anchor lists, passing through two sides of the routing holes, to shift routing path for load balance. Moreover, we extend EDGR into three-dimensional (3D) sensor networks to provide energy-aware routing for routing hole detour. Simulation results demonstrate that EDGR exhibits higher energy efficiency, and has moderate performance improvements on network lifetime, packet delivery ratio, and delivery delay, compared to other geographic routing protocols in WSNs over a variety of communication scenarios passing through routing holes. The proposed EDGR is much applicable to resource-constrained WSNs with routing holes.

Although the back-pressure (BP) algorithm has been proven to be a throughput-optimal policy for traffic scheduling and routing in wireless networks, the optimal control of delays in the BP algorithm remains an open problem, especially for conventional multihop networks. To enhance the delay performance, we proposed an improved BP algorithm called sojourn-time-based BP (STBP) by introducing a novel delay metric called the sojourn time backlog (STB). The STB considers the queue length and accumulated packet delays comprehensively. It provides more pressure to push forward flows suffering from greater delays. Based on this new metric, the calculation of the routing weight for each packet is determined for maximizing the difference of the STB in the routing process. The proposed routing algorithm is robust and distributed, and does not require any prior knowledge of network connections and load conditions. We analyze the network stability with delay considerations and prove the throughput optimality of the STBP in multihop networks. Simulation results reveal that the enhanced algorithm effectively improves the end-to-end delay while ensuring throughput optimality.

The application-specific network-on-chip (ASNoC) has been proposed as a promising solution to address the global communication challenges in terms of nanoscale system-on-chips. However, as the number of cores increases on chips, the power consumption and communication latency present major challenges for routing path allocation in ASNoCs. In this study, given the floorplan results and clustering of cores, we propose an efficient routing path allocation algorithm based on the Lagrangian relaxation for routing the traffic flows while minimizing the power consumption under constraints, such as latency constraints, physical link capacity constraints, and switch port constraints. In addition, we propose a modified shortest path algorithm based on the backtracking method to prevent deadlocks, which is critical for the correct operation of NoCs. Our experimental results demonstrate the effectiveness of the proposed method; the method has power overheads of less than 1% compared with designs that do not support a deadlock removal method.

Networks-on-chips (NoCs) are gaining in popularity as replacement for shared medium interconnects in chip-multiprocessors (CMPs) and multiprocessor systems-on-chips, and their performance becoming essential to system performance. There have been emerging studies to achieve better power/energy efficiency without performance degradation on NoCs. However, there are still non-negligible latency issues caused by the mechanism of power efficient approaches. To alleviate the latency problem and to transfer data efficiently with the high utilization of interconnect resources, we propose an on-chip network architecture that improves latency and bandwidth. Increasing the data/link widths across the network may considerably resolve this problem but is a costly proposition both in terms of device area and of power. Alternatively, we propose a dual-path router architecture that efficiently exploits path diversity to attain low latency without significant hardware overhead. By: 1) doubling the number of injection and ejection ports; 2) splitting packets into two halves; 3) recomposing routing policy to support path diversity; and 4) provisioning the network hardware design, we can considerably enhance network resource utilization to achieve much higher performance in latency. The proposed simultaneous dual-path routing (SDPR) scheme outperformed the conventional dimension order routing (DOR) technique across synthetic workloads by 31%–40% in average latency and up to a 100% improvement in throughput performance running on a 49-core CMP. Our synthesizable model for the SDPR router and network provides accurate power and area reports. According to the synthesis reports, SDPR incurs insignificant overhead compared to the baseline XY DOR router.

With the exponential growth of content in recent years, users are primarily interested in obtaining particular content and are not concerned with the host housing the content. By treating content as a first class citizen, information- centric networks (ICN) seek to transform the Internet from a host-to-host communication model to a content-centric model. A key component of ICN is to cache content at storage-enabled routers. By caching content at in-network routers, network performance can be improved by delivering content from routers closer to the user and not from the origin servers (content custodians). In this article, we provide an overview of the state-of-the-art cache management and routing policies in ICN. We present a small comparison study of some state-of-the-art algorithms on a real Internet topology to help the reader appreciate how the different strategies compare against one another. Our simulation results demonstrate that it is hard to pick a winner among existing policies. We conclude the article with a discussion of open research questions.

The unmanned aerial system (UAS), as a typical aeronautical Ad-hoc network (AANET) system, which is composed of unmanned aerial vehicle clusters has a lot of advantages such as flexible deployment, excellent cost-benefit ratio and free from the effect of environment. It will be an important part of the space-sky information network in the future. Due to the fast-moving of nodes in AANET/UAS, the topology changes frequently. The routing overhead becomes huge and inefficient, and connectivity keeping becomes difficult. In this paper, a shortest path routing algorithm based on grid position no center(GPNC-SP algorithm) is proposed, which uses the logical grid distance to replace the original Euclidean distance to reduce the sensitivity of fast-moving nodes. This algorithm automatically computes and maintains the adjacency relationship and topology structure by perception and updating algorithm and adopts Dijkstra algorithm to achieve the shortest routing path. Also, a regional reconstruction strategy(RSS) is designed to optimize the routing path dynamically. At the same time, two metrics, i.e., the percentage of the effective communication area(Peca%) and the sensitivity with logical grid size (Sg) are used to determine the optional scope of logical grid width. Comparing with the two traditional typical routing protocols (DREAM and DSDV algorithms), this algorithm sacrifices a certain degree of communication distance to achieve better performances of network overhead, link stability, and calculating speed. The final simulation experiments under the Matlab environment demonstrate the effectiveness and practicality of this algorithm.

Detailed routing is an important stage in very large scale integrated physical design. Due to the extreme scaling of transistor feature size and the complicated design rules, ensuring routing completion without design rule checking (DRC) violations becomes more and more difficult. Studies have shown that the low routing quality partly results from nonoptimal net-ordering nature of traditional sequential methods. The concurrent routing strategy is always based on an NP-hard model, thus is at a disadvantage in runtime. In this paper, we present a novel concurrent detailed routing algorithm that routes all nets simultaneously. Based on the multicommodity flow model, detailed routing problem with complex design rule constraints is formulated as an integer linear programming. Some model simplification heuristics and efficient model solving algorithms are proposed to improve the runtime. Experimental results show that, the proposed algorithms can reduce the DRC violations by 80%, meanwhile can reduce wirelength and via count by 5% and 8% compared with an industry tool. In addition, the proposed algorithm is general that it can be adopted as an incremental detailed router to refine a routing solution, so the number of DRC violations that industry tool cannot fix are further reduced by 27%.

In a route with a network gap, a vehicle usually drops messages if it cannot find the next hop. In this case, communications may be disrupted. Therefore, it is very important to avoid network gaps when routing paths are established. This paper proposes a reliable routing scheme and aims to establish routing paths without network gaps to improve the packet delivery rate. In this scheme, a routing establishment algorithm based on road segments and virtual nodes is proposed. This algorithm can establish the routing paths without network gaps, so the packet loss caused by network gaps is avoided. Moreover, a message can be transmitted along the shortest routing path without a network gap, so the packet delivery rate is improved. Finally, this scheme is evaluated, and the data results show that the packet delivery rate is effectively improved.

In recent years, maritime and air crashes occur frequently. The existing rescue measures rely only on board satellite communications equipment, which makes it difficult to confirm the accurate positioning information and vital signs of drowning people. Recently, wireless sensor networks (WSN) are introduced to Maritime Search and Rescue (MSR). WSNs feature quick expansion, self-organization, and self-adaptation to the marine environment. However, the constant changing nodes location and link reliability in marine search and rescue WSN makes the routing metrics between nodes highly dynamic. Traditional routing protocols such as AODV that establish a fixed single route based on static nodes information will provide poor packet delivery rate and take no consideration of the limited energy on the irreplaceable WSN nodes. We propose to employ opportunistic routing which can make best use of the broadcast property of radio propagation. The forwarding decisions in opportunistic routing are only based on its neighbor’s information. No network-wide flooding is required to establish routes. In order to maintain the latest neighbor information and minimize the energy cost of collecting these information, we propose a light-weight time series based routing metric prediction method to deal with the high communication cost incurred by collecting the latest routing metrics between nodes. Results: Our implementation of opportunistic routing protocol achieved 30% more Packet Delivery Ratio compared to the traditional AODV protocol. Also opportunistic routing protocol with prediction performed slightly better than opportunistic routing protocol without prediction. Our approach generated 90% efficiency where as 60% efficiency was achieved using AODV protocol. In achieving this an additional 3% energy is consumed by the nodes. We feel additional 3% energy consumption to improve delivery greatly by 30% is a good tradeoff.

The energy Internet concept has been considered as a new development stage of the smart grid, which aims to increase the energy transmission efficiency and optimize the energy dispatching in time and space. Energy router is a core device in the energy Internet and it connects all the devices together into a net structure and manages power flows among them. The research work presented in this paper described the energy router's structure and function expectations from the network perspective, and improved the existing energy router design. Open shortest path first (OSPF) protocol and virtual circuit switching mode are referenced from the Internet in the energy local area network (e-LAN) design. This paper proposed a design of an energy routing algorithm based on graph theory in an e-LAN. A lowest cost routing selection algorithm is designed according to the features of power transmission, and a source selection and routing design algorithm is proposed for very heavy load conditions. Both algorithms have been verified by case analyses.

Greedy Forward is a well-known technique used by most of the geographic routing algorithms to forward packets to the node that is geographically closer to the destination node. It is the simplest form of the proposed geographic routing algorithms and it is particularly attractive in sensor networks by bringing additional advantages such scalability, dynamism, and high delivery rates. However, in the presence of a hole (or voids), greedy forward techniques tend to fail. Thus, a hole bypass solution needs to be used in order to route packets to a node where greedy forwarding process can be resumed. In this work, we propose a new geographic routing algorithm called REACT that can bypass routing holes and create routing paths toward the sink node. Our solution takes advantage of the higher communication range of the sink node and the Received Signal Strength Indicator (RSSI) to enable the construction of routing paths by self-electing the next hop at each step while also performing data aggregation. No extra packets are required to configure the routing task. Our results clearly show an efficient data delivery achieved by the proposed algorithm in scenarios with routing holes with all the benefits of a greedy forwarding technique.

The Interplanetary Internet is a network that interconnects objects traveling in space and on planets such as satellites, rovers and comets. This network has very different communication conditions than the networks deployed on the surface of Earth. The large delays, intermittent connections and rough environment in space require the adoption of the Delay/Disruption Tolerant Network architecture/techniques. The currently used implementation of DTN interplanetary networks uses the Contact Graph Routing mechanism that we show, using the Interplanetary Overlay Network (ION) based experiments, has some shortcomings leading to less efficient use of the network. In this paper, we propose a novel model to represent such networks based on temporal graphs obtaining a near-real-time representation of these deterministic dynamic networks. This Modified Temporal Graph (MTG) model is then used for the implementation of our proposed routing algorithm, the Earliest Arrival Optimal Delivery Ratio (EAODR) routing algorithm. We provide the proof of correctness of EAODR, and we use our routing simulator to run experiments on a real-world network and also on large networks. We prove that EAODR outperforms the Contact Graph Routing (CGR) in terms of a decrease in delay of up to 12.9%.

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.

Static path optimization (SPO) is a foundation of computational intelligence, but in reality, the routing environment is usually time-varying (e.g., moving obstacles, spreading disasters and uncertainties). Thanks to scientific and technical advances in many relevant domains nowadays, changes in the routing environment are often more or less predictable. This study mainly focuses on path optimization in a given dynamic routing environment (POGDRE). A common practice to deal with dynamic routing environment is to conduct online re-optimization (OLRO), i.e., at each time t , environmental parameters are measured/predicted first, and then the best path is re-calculated by resolving SPO based on the newly measured/predicted environmental parameters. In theory, POGDRE is equivalent to time-dependent path optimization (TDPO), which is usually resolved as SPO on a time-expanded hypergraph (TEHG) with a significantly enlarged size. In other words, during a single online run of OLRO-based methods or a single run of TEHG-based methods, the route network is actually fixed and static. Inspired by the multi-agent co-evolving nature reflected in many methods of evolutionary computation, this paper proposes a methodology of co-evolutionary path optimization (CEPO) to resolve the POGDRE. Distinguishing from OLRO and TEHG methods, in CEPO, future routing environmental parameters keep changing during a single run of optimization on a network of original size. In other words, the routing environment co-evolves with the path optimization process within a single run. This paper then reports a ripple-spreading algorithm (RSA) as a realization of CEPO to resolve the POGDRE with both optimality and efficiency. In just a single run of RSA, the optimal actual travelling trajectory can be achieved in a given dynamic routing environment. Simulation results clearly demonstrate the effectiveness and efficiency of the proposed CEPO and RSA for addressing the POGDRE.

In table routing protocols such as link state routing, every node in the network periodically broadcasts its link state and the state of its neighbors. These routing updates result in the transmission of a large number of packets. Some of these packets contain correlated or even redundant data which could be compressed if there is central management in the network. However, in autonomous networks, each node acts as a router, in which case central coordination is not possible. In this paper, compressed sensing is used to reduce routing traffic overhead. This can be done at nodes which have greater processing capabilities and no power consumption limitations such as backbone nodes in wireless mesh networks. A method is proposed to select a subset of nodes and thus a subset of links to probe their state. The sensed states are encoded to generate a low dimension sampled vector. This compressed link state vector is broadcast to the entire network. Nodes can then reconstruct link states from this vector using side information. Performance results are presented which demonstrate accurate anomaly detection while adapting to topology changes. Further, it is shown that a proper choice of weighting coefficients in the sampling process can improve detection performance.

In this article, we consider a variant of Open Shortest Path First (OSPF) routing that accounts for Random Early Detection (RED), an Active Queue Management method for backbone networks. In the version of OSPF we consider in this article we only require a single network path be available between each origin and destination, a simplification of the OSPF protocol. We formulate a mixed integer non-linear program to determine the data paths, referred to as a routing policy. We prove that determining an optimal OSPF routing policy that accounts for RED is NP-Hard. Furthermore, in order for the generated routing policies to be real-world implementable, referred to as realizable, we must determine weights for all arcs in the network such that solving the all-pairs shortest path problem using these weights reproduces the routing policies. We show that determining if a set of all-pairs routes is realizable is also NP-Hard. Fortunately, using traffic data from three real-world backbone networks, we are able to find realizable routing policies for these networks that account for RED, using an off-the-shelf solver, and policies found perform better than those used in each network at the time the data was collected.

Quality of Service (QoS) assurance in Wireless Sensor Network (WSN) is a tough task, and it is more exciting due to the scarcity of resources. The requirement of different WSN applications running over has different constraints. In QoS, routing protocol the network has to balance the traffic. This paper presents a novel heuristic routing algorithm known as QoS assured Multi-objective Hybrid Routing Algorithm (Q-MOHRA) for Heterogeneous WSN. Q-MOHRA takes into account the link (energy, hop count, link quality indicator etc.) and path (jitter) metrics for optimal path selection. The performance of Q-MOHRA is evaluated through intensive simulation and equated with Simple Hybrid Routing Protocol (SHRP) and Dynamic Multi-objective Routing Algorithm (DyMORA). The metrics such as average energy consumption, residual energy, packet delivery ratio, jitter, and normalized routing load are used for comparison. The performance of Q-MOHRA has been observed to outclass SHRP and DyMORA. It improves the packet delivery ratio by 24.31% as compared to SHRP and 11.86% as compared to DyMORA. Q-MOHRA outperforms DyMORA in terms of average energy consumption by a factor of 8.27%.

Information-centric networking (ICN) is gradually becoming the alternative approach to the traditional Internet architecture through enlightening information (content) distribution on the Internet with content names. The growing rate of Internet traffic has adapted the content-centric architectures to better serve the user requirement of accessing data. Routing disseminates preliminary topology and strategy information as well as long-term changes in them and computes the routing table to coordinate the forwarding procedure. A good routing scheme is essential to reduce delay and to enhance the performance of the network with an efficient searching of the desired content item. In this paper, we present a novel scheme for ICN which evaluates the path for searching the desired content item with an efficient lookup process and we call as Intelligent Routing (IR). Our implement IR scheme utilizes the concept of ternary digital search for making an efficient lookup and evaluates the satisfaction score for making a forwarding decision. The simulation results recommend that IR scheme can reliably accomplish the better performance across other hashing and routing approaches proposed in this field.

In recent years, the idea of wireless three-dimensional network-on-chips (3D NoCs) was promoted in order to design many-core chips with greater performance and lower energy consumption. This technology is the combination of different dies that are stacked on each other. Therefore, it is necessary to propose a suitable routing mechanism for irregular wireless 3D NoCs that can support the agnostic topologies. In this paper, we propose a deadlock-free routing algorithm for wireless 3D NoCs, called Floyd-base Inter-chip Traffic distribution (FIT), which is based on Floyd routing algorithm. In FIT algorithm, the number of hops is reduced compared to the already established deterministic algorithms; moreover, the traffic distribution is improved. Evaluation results show that our proposed routing algorithm significantly improves the performance and throughput by reducing the energy consumption, the average hop count and the communication latency.

Delay Tolerant Networks (DTNs) often suffer from intermittent disruption and variable long delay due to factors such as mobility and energy. In this paper, a Location Aided Controlled Spraying (LACS) routing algorithm is proposed to deal with the challenging issues in DTN routing. Only the routing information carried by the contacted nodes is needed in this algorithm, and there is no need for global networks knowledge and hardware support. The routing process is divided into two stages, i.e., controlled spraying routing stage and single-copy routing stage. The maximum transfer throughput of the contact is checked before each message is forwarded. During the controlled spraying stage, the current node adjusts spraying strategy according to the encounter angle of the contact nodes. During the single-copy stage, a location prediction model based on the semi-Markov process (SMP) is introduced, and the node's behaviors can be captured both in the temporal and spatial domains with this model. The current node predicts the destination node's location, and then decides whether to forward the message to target node based on the time used for meeting the destination node. Simulation results show that the proposed algorithm can achieve better performance than the traditional routing schemes of DTNs in terms of delivery ratio, network overhead and transmission delay under both random node movement model and realistic trace scenario.

Routing protocols properties form an essential topic of research. Ensuring that a routing protocol is stable, loop free and reaches the global optimal topology solution is needed for both evaluating it and doing the required enhancements for it. There exist several trials in previous researches to enhance routing protocols. Those works depend on either theoretical models or simulation to validate their results. Existing validation models target lexical based routing metrics only. In this work, we propose a validation model for non-lexical routing metrics (such as Enhanced Interior Gateway Routing Protocol – EIGRP). Our validation model is based on abstract algebra. It helps in validating necessary routing properties and enhancing existing routing protocols in such a way that makes them meet those properties.

The advancements made in the wireless sensor networks have enabled the research communities to delve into the study of spatial reusability concepts. Due to the restricted capacity in wireless links, it is a significant to select the optimal route for packet transmission. The achievement of optimal route selection is verified by the high end-to-end throughput rate. Routing in WSNs is very challenging due to the inherent characteristics that distinguish these networks from other wireless networks like mobile ad hoc networks or cellular networks. In this paper, we have proposed an improved spatial reusability process using Single Path and Anypath Routing Protocols (SSAAR). The task of single path routing is to minimize the cost of the nodes in wireless links, whereas the task of any path routing is to assists the intermediate node who overhears the packet to participate in packet forwarding. Experimental results have shown the efficacy of our proposed work in terms of cost minimization functionalities.

Sensor networks designed especially for the multimedia applications require high data rate and better Quality of Service (QoS). Offering a reliable and energy efficient routing technique in a harsh and complex three-dimensional (3-D) environment for multimedia applications is a challenging job. Geo-routing and geometric routing have been efficient routing schemes for two-dimensional (2-D), but are unable to work properly for 3-D sensor networks. In order to enhance the resilience to link the dynamics in the 3-D sensor network, in this research an Enhanced Reliable Reactive Routing (ER3) is proposed. ER3 is an advancement to the existing reactive routing schemes, to provide energy efficient and reliable routing of data packets in the complex 3-D sensor networks for multimedia applications. The major attraction of ER3 is its backoff scheme, which occurs in the route discovery phase. In backoff scheme robust pilot paths formed between the source and destination are calculated to enable cooperative forwarding of the data packets. The data packets in ER3 are forwarded greedily to the destination from the source and doesn’t require any prior location information of the nodes. The encompassing simulations suggest that the ER3 outperforms the existing routing protocols on the basis of energy efficiency, low latency and high packet delivery ratio.

In this study, the authors improve the faster criterion in vehicle routing by extending the bi-delta distribution to the bi-normal distribution, which is a reasonable assumption for travel time on each road link. Based on this assumption, theoretical models are built for an arbitrary path and subsequently adopted to evaluate two candidate paths through probabilistic comparison. Experimental results demonstrate the bi-normal behaviour of link travel time in practice, and verify the faster criterion's superiority in determining the optimal path either on an artificial network with bi-normal distribution modelling link travel time or on a real road network with real traffic data. This study also validates that when the link number of one path is large, the probability density function of the whole path can be simplified by a normal distribution which approximates the sum of bi-normal distributions for each link.

In this paper, we have exploited the weight trusted routing (WTR) mechanism to detect and eliminate the malicious nodes involved during the routing path formation in smart-home environments where the routing between the communicating entities is performed through the mesh architecture. Further, to provide a secure communication against malicious behavior of nodes, the proposed mechanism uses Dijkstra’s shortest path routing algorithm in which the weights are deliberated using certain parameters such as node-distance, packet-loss and trust value of each node which is computed using social impact theory optimizer. Moreover, we have presented the network performance trade-off caused by secure path formation with conventional method and have proposed the WTR mechanism for eliminating the potential issues such as packet-loss ratio, end-to-end delay and network throughput. The commercial simulator NS2 is used to simulate and compare the network metrics for both conventional as well as proposed approach and is validated with experimental results over end-to-end delay and message delivery ratio against reported literature.

Asynchronous sleep schedule and geographical routing are two efficient and scalable solutions for wireless sensor networks (WSNs). However, the schedule may degrade the delay performance of the routing protocol, and the optimal combined utilization of these two solutions is still an open question. In this letter, we propose a geographical-based opportunistic routing protocol for asynchronous WSNs. Each node maintains multiple relay candidates that make geographical progresses of more than a threshold $\gamma$ , and opportunistically forwards data packet to the first candidate that wakes up. We can obtain the optimal end-to-end delay performance, by just tuning $\gamma$ . Analytical and simulation results show that the derived optimal $\gamma$ can make a good tradeoff between the single-hop delay and the hop count of forwarding path, and minimize the end-to-end delay of forwarding path.

In recent years, the bio-inspired solution has been employed to address routing optimization issue intelligently without manual intervention. In this paper, we propose a novel Ant Colony Optimization (ACO)-inspired Information-Centric Networking (ICN) Routing mechanism (ACOIR) by mapping ACO into ICN. At first, we devise a content management strategy based on the storage of name prefix to help conveniently and effectively manage and provide contents. Secondly, we propose a continuous model for content concentration by considering dynamic environment to conduct interest forwarding. Thirdly, we give a computation scheme about forwarding probability with physical distance and content concentration considered to determine the forwardable outgoing interface. Finally, we propose a comprehensive routing mechanism based on probabilistic forwarding to retrieve the most suitable content copy. We evaluate the proposed ACOIR, and the experimental results demonstrate that ACOIR can obtain the optimal solution and has better performance than other methods.

In mobile Ad Hoc networks (MANETs), flooding-based route discovery is usually preferred in order to set up the route with reliability between transmission pair. However, this approach may cause a serious contention in transmission between adjacent nodes and a considerable amount of control packets. In addition, most of Ad Hoc routing protocols establish the route with minimum hop count. Consequently, the performance of Ad Hoc routing protocol is considerably affected by link (or route) duration since the network comprises the nodes with unrestricted mobility and constrained range in transmission. This paper proposes novel routing protocol that aims to (1) minimize routing overhead in route discovery procedure, and (2) guarantee a reliable and fast packet delivery between source and destination, especially in providing real-time applications over MANETs. To achieve this objective, we introduce relay region (RR) within the transmission range of nodes in order to select optimal next relaying nodes for supporting specific application requirements in route discovery procedure. The RR is defined by the limited distance progress in transmission to next relaying node in order to maintain the established route for an arbitrary length of time (i.e., route duration) while meeting packet delivery reliability and delay constraints. In performance evaluation, the simulation results showed that the proposed scheme can significantly improve the performance in comparison with the previous routing algorithms in terms of packet delivery ratio and packet delivery latency, reducing transmission redundancy in route discovery procedure.

In this paper, we present a cooperative multihop transmission scheme for two-way amplify-and-forward (AF) relay networks. Based on a symbol error probability (SEP) analysis and using geographic information, we derive the maximum one-hop distance for a networking node under a given SEP and develop a next-hopping-node selection scheme. With these results, we then propose a routing protocol based on a greedy algorithm to realize the transmission scheme, where a routing path consisting of a number of independent two-way AF relaying procedures is built to connect the two sources. As compared to a previous related work, the proposed approach removes the utilization limitation and improves the routing efficiency. Computer simulation results also show that it provides a higher probability of successfully building a routing path with close effective throughput for most cases of interest.

Aiming at the problem of failure recovery in current networks, a fast failure recovery method based on equivalent cooperative routing is proposed. Firstly, the transmission path between the source and destination nodes is divided into several non-overlapping path segments. Next, backup paths are deployed for each link in the path segment through segmented routing technology, which ensures fast routing recovery after failure. Additionally, in order to avoid damaging the QoS of the data stream through the failure recovery process, the transmission is guaranteed by the intersegment QoS complement. The experimental results show that the proposed method has a low failure recovery delay under a relatively small flow table cost.

Privacy-preserving routing protocols in wireless networks frequently utilize additional artificial traffic to hide the identities of communicating source-destination pairs. Usually, the addition of artificial traffic is done heuristically with no guarantees that the transmission cost, latency, and so on, are optimized in every network topology. In this paper, we explicitly examine the privacy-utility tradeoff problem for wireless networks and develop a novel privacy-preserving routing algorithm called optimal privacy enhancing routing algorithm (OPERA). OPERA uses a statistical decision-making framework to optimize the privacy of the routing protocol given a utility (or cost) constraint. We consider global adversaries with both lossless and lossy observations that use the Bayesian maximum-a-posteriori (MAP) estimation strategy. We formulate the privacy-utility tradeoff problem as a linear program, which can be efficiently solved. Our simulation results demonstrate that OPERA reduces the adversary’s detection probability by up to 50% compared to the random Uniform and Greedy heuristics, and up to five times compared to a baseline scheme. In addition, OPERA also outperforms the conventional information-theoretic mutual information approach.

In this article, we are going to discuss the comparison of three different categories of routing principles, namely, flat routing, hierarchical routing and location-based routing in Wireless Sensor Networks. Under the flat routing strategies, we are going to discuss 1-D flooding and 2-D flooding. Under the hierarchical category, we will explore spanning tree and under the location-based routing category, we will use angle-based dynamic path construction. For all these four algorithms, on the basis of a precise energy modelling and MAC layer modelling, comparison is made out on the basis of energy consumption and delay incurred for the transmission of data from the sensing nodes via the forwarding nodes and ultimately converging at the sink node. Also, retransmission probability, an important criterion, is taken into consideration and its effect on energy consumption and end-to-end delay is observed.

Efficient and reliable routing plays a key role in wireless sensor networks in which routing design with regard to network availability and node lifetime needs to be deliberately considered. When multi-hop relay transmission is frequently applied to reduce a source node's energy consumption and improve network capacity, a key issue affecting the nodes' participation in the transmission is the problem of suitably determining the next hop in order to prolong each node's lifetime and to maintain the energy-balancing of the whole network. In this study, we propose an energy-aware routing scheme by taking the Cauchy operator, node's residual energy and routing distance into account. Based on Cauchy inequation, we achieve a relationship between the routing distance and the energy usage in the routing. By fixing a relay selection parameter and then identifying the next hop appropriately, we obtain a balancing energy-aware routing algorithm. Numerical results are provided to verify the lifetime and equilibrium of the energy distribution by comparing with them with those of a traditional approach.

The Green Routing and Scheduling Problems deal with the models which relate to ecological issues. For modeling routing and transportation processes characterized by subjectivity, ambiguity, uncertainty and imprecision, fuzzy logic approach happens to be a very promising mathematical approach.The present investigation discusses about the multi objective fuzzy shortest path selection, where the arc lengths are expressed as trapezoidal fuzzy numbers. The shortest paths can be distinguished by using the highest degree of similarity measure. The optimal path selected depends on the different weights given to the MOFSP in the network. The decision maker can select the best one or the most satisfactory solution depending on the priority and nature of the problem. The algorithms are illustrated with a bi-objective optimization problem with crisp and trapezoidal fuzzy values. The numerical experimentation is used to evaluate the proposed model. The experiment results of the proposed model prove that the results lead to the selection of shortest path as a standard algorithm.

Vehicular Ad-hoc network (VANET) is a self-organized ad hoc network. VANET becomes a most challenging research area as it has several issues related to routing protocols, quality of service, security, etc. Vehicular communication is critically unsafe to several kinds of active and passive routing attacks. This paper analyzes the impact of a compromised node (vehicle) on zone routing protocol and ad-hoc on-demand distance vector, and recommends a suitable solution called secure vehicular on demand routing to find out and mitigate the black hole attack. The given study analyses the effect of vehicle density on the average throughput, packet delivery ratio, end-to-end delay, normalized routing load and average path length.

In this paper, we propose a new routing protocol called the Least Common Multiple based Routing (LCMR) for load-balanced multipath routing in Mobile Ad hoc NETworks (MANETs). First, we find multiple paths between a source to a destination, when those exist, along with the estimates of the time to route a packet along each of these paths. The data packets originating from the source to the destination are then distributed along these multiple paths in such a way that the number of data packets sent along any such path is inversely proportional to the routing time through this path. This distribution strategy keeps the load balanced along all the paths so that the overall routing time for sending the data packets is minimized. Routes between a given source-destination pair are discovered in a way similar to that in the Ad hoc On-demand Distance Vector (AODV) routing protocol with the difference that instead of the number of hops, the routing time for reaching the destination along every route is measured, and multiple routes, if those exist, will also be determined by the route discovery process. Our proposed technique for distribution of packets along different routes is very elegant with a better performance than the existing load-balanced routing protocols like Fibonacci Multipath Load Balancing (FMLB) and Multiple AODV (MAODV), as established from a theoretical analysis as well as through simulation results.

In this paper we propose a game theoretic framework for stochastic multipath routing in mobile ad hoc networks (MANETs). In a MANET, intelligent and adaptive attackers may try to hijack, jam or intercept data packets traveling from source to destination. In our proposed game, at each stage the source node keeps track of the available multiple paths, the residual bandwidth of the paths and the strategy of the attackers from the information gathered during the previous stage. Based on these observations, the source node selects a path for data communication and switching strategy among the multiple established paths between the source node and the destination node. Accordingly, it selects an optimal routing strategy to send data packets to the destination at each stage of the game. Using minimax-Q learning, the selected routing strategy maximizes the expected sum of per stage discounted payoff, which is the utilization of residual bandwidth between a source–destination pair along with the probability that the path is safe. Performance analysis and numerical results show that our proposed scheme achieves significant performance gains in terms of residual bandwidth utilization, average end-to-end delay, packet delivery ratio, routing overhead and security.

This article explores a structural neighborhood decomposition for arc routing problems, in which the decisions about traversal orientations during services are made optimally as part of neighbor evaluation procedures. Using memory structures, bidirectional dynamic programming, and lower bounds, we show that a large neighborhood involving classical moves on the sequences of services along with optimal orientation decisions can be searched in amortized O(1) time per move evaluation instead of O(n) as in previous works. Because of its generality and now-reduced complexity, this approach can be efficiently applied to several variants of arc routing problems, extended into large neighborhoods such as ejection chains, and integrated into two classical metaheuristics. Our computational experiments lead to solutions of high quality on the main benchmark sets for the capacitated arc routing problem (CARP), the mixed capacitated general routing problem (MCGRP), the periodic CARP, the multidepot CARP, and the min-max k-vehicles windy rural postman problem, with a total of 1,528 instances. We also report sensitivity analyses for new MCGRP instances with turn penalties, which are uncommonly challenging yet critical for many practical applications. The e-companion is available at https://doi.org/10.1287/opre.2017.1595