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MANETs are networks of mobile devices for multihop communication without a separate infrastructure for routing and control. If robust protocols are available, MANETs can exploit the true ubiquity of everyday mobile devices for application scenarios such as collaborative learning, multiplayer gaming, adaptive advertising as well as in disaster management and battlefield communication. Traditional schemes such as reactive, proactive and hybrid routing incur costs of often O(n 2) for discovering and maintaining routes or node hierarchies for networks with n number of nodes. These routes or node structures become obsolete rapidly due to MANET dynamics resulting from mobility, limited battery life, and impairments of wireless links. These traditional approaches are based on a paradigm that we refer to as fixed-stateful routing. The routing paradigm that best matches the ubiquity of devices in a MANET is mobile-stateless routing. In mobile-stateless routing, nodes do not keep global network states or play special roles as control nodes. We propose flooding as an end to end packet delivery mechanism and introduce the concept of endcast that allows the communication from a single source to a single destination in which the data is carried by controlled flooding and the data propagation is inhibited after reaching the destination. Problem statement Simple flooding causes excessive packet redundancy resulting in collisions and contention which is known as broadcast storm problem. We introduce the term broadcast flood problem to refer to the propagation of data beyond the destination in flooding operation. This research is aimed at modeling endcast and developing an endcast scheme to enable MANET nodes to perform end to end communication in mobile-stateless manner. Solution We built a theoretical model to analyze the endcast concept. This model includes methods to quantify broadcast storm problem and broadcast flood problem. Based on this model, we proposed an endcast scheme that controls the storm situation using counter-based flooding and the flood situation using negative acknowledgement packets. The storm control scheme is inspired by the chalone mechanism that regulates growth of biological organs. The proposed scheme is in the mobile-stateless routing paradigm because the nodes keep only a set of local states in the form of a log of received data packets and the nodes do not act as infrastructure nodes. We apply the theoretical model on the proposed endcast scheme to validate its correctness and simulations were done to verify the performance.

As the promising communication architecture for future networks, the content-centric network (CCN) is still facing many challenges. In CCNs, it is difficult to discover temporary content replicas spreading in routers' caches based on the routing information provided by proactive routing protocols. This paper proposes an advanced perceptive forwarding strategy (APFS), which adaptively perceives closer temporary content replicas to respond the users' requests quickly. A data structure, called a chunk map (CM), is designed and is included into a data packet to indicate the availability of the content replicas in the cache of a closer router. The routers that have received the CM seem to perceive the closer content replicas so that they would intelligently forward the users' requests to the closer routers that cache the requested content replicas. Moreover, a new policy, called early start with punishment, is put forward to guarantee the adaptability of the CM probing and an improved cache replacement policy is employed to extend the validity duration of the CM. The simulation result shows that our APFS scheme has the noticeable performance in terms of the download delay and the average bandwidth. Published version

With the occurrence of Internet of Things (IoT) era, the proliferation of sensors coupled with the increasing usage of wireless spectrums especially the ISM band makes it difficult to deploy real-life IoT. Currently, the cognitive radio technology enables sensors transmit data packets over the licensed spectrum bands as well as the free ISM bands. The dynamic spectrum access technology enables secondary users (SUs) access wireless channel bands that are originally licensed to primary users. Due to the high dynamic of spectrum availability, it is challenging to design an efficient routing approach for SUs in cognitive sensor networks. We estimate the spectrum availability and spectrum quality from the view of both the global statistical spectrum usage and the local instant spectrum status, and then introduce novel routing metrics to consider the estimation. In our novel routing metrics, one retransmission is allowed to restrict the number of rerouting and then increase the routing performance. Then, the related two routing algorithms according to the proposed routing metrics are designed. Finally, our routing algorithms in extensive simulations are implemented to evaluate the routing performance, and we find that the proposed algorithms achieve a significant performance improvement compared with the reference algorithm.

Ever-increasing demands for portable and flexible communications have led to rapid growth in networking between unmanned aerial vehicles often referred to as flying ad-hoc networks (FANETs). Existing mobile ad hoc routing protocols are not suitable for FANETs due to high-speed mobility, environmental conditions, and terrain structures. In order to overcome such obstacles, we propose a combined omnidirectional and directional transmission scheme, together with dynamic angle adjustment. Our proposed scheme features hybrid use of unicasting and geocasting routing using location and trajectory information. The prediction of intermediate node location using 3-D estimation and directional transmission toward the predicted location, enabling a longer transmission range, allows keeping track of a changing topology, which ensures the robustness of our protocol. In addition, the reduction in path re-establishment and service disruption time to increase the path lifetime and successful packet transmissions ensures the reliability of our proposed strategy. Simulation results verify that our proposed scheme could significantly increase the performance of flying ad hoc networks.

A heterogeneous ring domain communication topology with equal area in each ring is presented in this paper in an effort to solve the energy balance problem in original IPv6 routing protocol for low power and lossy networks (RPL). A new clustering algorithm and event-driven cluster head rotation mechanism are also proposed based on this topology. The clustering information announcement message and clustering acknowledgment message were designed according to RFC and original RPL message structure. An energy-efficient heterogeneous ring clustering (E2HRC) routing protocol for wireless sensor networks is then proposed and the corresponding routing algorithms and maintenance methods are established. Related messages are analyzed in detail. Experimental results show that in comparison against the original RPL, the E2HRC routing protocol more effectively balances wireless sensor network energy consumption, thus decreasing both node energy consumption and the number of control messages.

In wireless multi-hop networks, especially large scale wireless multi-hop networks, the feasibility of routing strategies is of vital significance. However, the basic function of routing strategies, the ability of finding a path from source to destination, is seldom researched. In this paper, we apply a Markov chain to model the routing discovery process of wireless multi-hop networks with arbitrary routing strategies. Taking the fading characteristics of wireless channel into consideration, we analyze the impacts of weak links on routing algorithms in wireless multi-hop networks. The probability of routing success and the distribution of hop count are discussed in detail and their close-form solutions are given. Simulation and theoretical results show that, with the increase of the network scale, the impact of weak links gets stronger and even makes the routing strategies unusable. Our research has pointed out the relations between the performance of routing strategies and the network scale under the impact of weak links. The results have important significance for routing strategy designing and network planning.

Conventionally, vehicle routing problems are defined on a network in which the customer locations and arcs are given. Typically, these arcs somehow represent the distances or expected travel time derived from the underlying road network. When executed, the quality of the solutions obtained from the vehicle routing problem depends largely on the quality of the road network representation. This paper explicitly considers path selection in the road network as an integrated decision in the time-dependent vehicle routing problem, denoted as path flexibility (PF). This means that any arc between two customer nodes has multiple corresponding paths in the road network (geographical graph). Hence, the decisions to make are involving not only the routing decision but also the path selection decision depending upon the departure time at the customers and the congestion levels in the relevant road network. The corresponding routing problem is a time-dependent vehicle routing problem with path flexibility (TDVRP–PF). We formulate the TDVRP–PF models under deterministic and stochastic traffic conditions. We derive important insights, relationships, and solution structures. Based on a representative testbed of instances (inspired on the road network of Beijing), significant savings are obtained in terms of cost and fuel consumption, by explicitly considering path flexibility. Having both path flexibility and time-dependent travel time seems to be a good representation of a wide range of stochasticity and dynamics in the travel time, and path flexibility serves as a natural recourse under stochastic conditions. Exploiting this observation, we employ a Route-Path approximation method generating near-optimal solutions for the TDVRP–PF under stochastic traffic conditions.

In this paper, we propose an extension of the vehicle routing problem with cross-docking that takes into account resource constraints at the cross-dock. These constraints limit the number of docks that can be used simultaneously. To solve this new problem, we adapt a recently proposed matheuristic based on large neighborhood search. In particular, we focus on the feasibility tests for insertions and compare heuristics and constraint programming strategies. Finally, computational experiments on instances adapted from the vehicle routing problem with cross-docking are reported. They give insights on the impact of a limited cross-dock capacity on the routing cost.

A novel resilient coarse granularity optical routing network architecture that adopts finely granular protection and finely granular add/drop is presented. The routing scheme defines optical pipes such that multiple optical paths can be carried by each pipe and can be dropped or added at any node on the route of a pipe. The routing scheme also makes it possible to enhance frequency utilization within pipes, by denser path packing in the frequency domain, as we recently verified. We develop a static network design algorithm that simultaneously realizes the independence of working and backup paths and pipe location optimization to efficiently carry these paths. The design algorithm first sequentially accommodates optical paths into the network, then tries to eliminate sparsely utilized fibers and iteratively optimizes frequency slot/wavelength assignment in each coarse granular pipe so as to limit the impairment caused by dropping the optical paths adjacent in the frequency domain. Numerical experiments elucidate that the number of fibers in a network can be reduced by up to 20% for 400Gbps channels without any modification in hardware.

In recent years, as wireless sensor networks (WSNs) are widely diffused, multiple overlapping WSNs constructed on the same area become more common. In such a situation, their lifetime is expected to be extended by cooperative packet forwarding. Although some researchers have studied about cooperation in multiple WSNs, most of them do not consider the heterogeneity in the characteristics of each WSN such as battery capacity, operation start time, the number of nodes, nodes locations, energy consumption, packet size and/or data transmission timing, and so on. In a heterogeneous environment, naive lifetime improvement with cooperation may not be fair. In this paper, we propose a fair cooperative routing method for heterogeneous overlapped WSNs. It introduces an energy pool to maintain the total amount of energy consumption by cooperative forwarding. The energy pool plays a role of broker for fair cooperation. Finally, simulation results show the excellent performance of the proposed method.

A routing grid for Self-Aligned Quadruple Patterning (SAQP) helps to find a valid routing of SAQP, but it is not easy to find it. The routing of SAQP on the grid consists of three types of routing. Among them, third type has turn prohibition constraint on the grid. Typical routing algorithms often fail to find a valid routing for third type. In this paper, SAQP compliant two dimensional routings are found on the grid by finding an optimal valid tertiary routing effectively. Experiments show that SAQP compliant routings are found efficiently.

We consider dynamic routing in multi-hop wireless networks with adversarial traffic. The model of wireless commu- nication incorporates interferences caused by packets’ arrivals into the same node that overlap in time. We consider two classes of adversaries: balanced and unbalanced. We demonstrate that, for each routing algorithm and an unbalanced adversary, the algorithm is unstable against this adversary in some networks. We develop a routing algorithm that has bounded packet latency against each balanced adversary.

We present a bio-inspired unicast routing protocol for vehicular Ad Hoc Networks which uses the cellular attractor selection mechanism to select next hops. The proposed unicast routing protocol based on attractor selecting (URAS) is an opportunistic routing protocol, which is able to change itself adaptively to the complex and dynamic environment by routing feedback packets. We further employ a multi-attribute decision-making strategy, the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), to reduce the number of redundant candidates for next-hop selection, so as to enhance the performance of attractor selection mechanism. Once the routing path is found, URAS maintains the current path or finds another better path adaptively based on the performance of current path, that is, it can self-evolution until the best routing path is found. Our simulation study compares the proposed solution with the state-of-the-art schemes, and shows the robustness and effectiveness of the proposed routing protocol and the significant performance improvement, in terms of packet delivery, end-to-end delay, and congestion, over the conventional method.

Among the main issues in the theory of geometric grids on spatial information systems, is the problem of finding the shortest path routing between two points. In this paper tried to using the graph theory and A* algorithms in transport management, the optimal method to find the shortest path with shortest time condition to be reviewed. In order to construct a graph that consists of a network of pathways and modelling of physical and phasing area, the shortest path routes, elected with the use of the algorithm is modified A*.At of the proposed method node selection Examining angle nodes the desired destination node and the next node is done. The advantage of this method is that due to the elimination of some routes, time of route calculation is reduced.

Geographic routing has gained much attention as a basic routing primitive inwireless sensor networks due to its memory-less, scalability, efficiency and low overheadfeatures. Greedy forwarding is the simplest geographic routing scheme, it uses the distanceas a forwarding criterion. Nevertheless, it may suffer from communication holes, whereno next hop candidate is closer to the destination than the node currently holding thepacket. For this purpose, a void handling technique is needed to recover from the voidproblem and successfully deliver data packets if a path does exist between source anddestination nodes. Many approaches have been reported to solve this issue at the expenseof extra processing and or overhead. This paper proposes GRACO, an efficient geographicrouting protocol with a novel void recovery strategy based on ant colony optimization(ACO). GRACO is able to adaptively adjust the forwarding mechanism to avoid theblocking situation and effectively deliver data packets. Compared to GFG, one of the bestperforming geographic routing protocols, simulation results demonstrate that GRACOcan successfully find shorter routing paths with higher delivery rate, less control packetoverhead and shorter end-to-end delay.

The greedy strategy of geographical routing may cause the local minimum problem when there is a hole in the routing area. It depends on other strategies such as perimeter routing to find a detour path, which can be long and result in inefficiency of the routing protocol. In this paper, we propose a new approach called Intermediate Target based Geographic Routing (ITGR) to solve the long detour path problem. The basic idea is to use previous experience to determine the destination areas that are shaded by the holes. The novelty of the approach is that a single forwarding path can be used to determine a shaded area that may cover many destination nodes. We design an efficient method for the source to find out whether a destination node belongs to a shaded area. The source then selects an intermediate node as the tentative target and greedily forwards packets to it, which in turn forwards the packet to the final destination by greedy routing. ITGR can combine multiple shaded areas to improve the efficiency of representation and routing. We perform simulations and demonstrate that ITGR significantly reduces the routing path length, compared with existing geographic routing protocols.

Location-based routing protocols use position information for making packet forwarding decisions, assuming perfect location information. Unlike topological routing algorithms, they do not need to exchange and maintain routing information. They work nearly stateless. However, in practice there could be significant errors in obtaining location estimates. In this paper, the impact of location errors on power consumption of these protocols will be analyzed via developing a mathematical model represents the location errors that may occur in real deployment. Then a simulation of the power consumption of two location-based routing protocols, Geographic Random Forwarding (GeRaf) and Minimum Energy Consumption Forwarding (MECF), is carried out to evaluate the mathematical model. Both the obtained simulation results and the developed mathematical model show that this type of routing protocols suffers from substantial performance degradation in terms of power consumption in presence of location errors.

In this paper, popular routing protocols for Wireless Sensor Networks (WSNs) are studied. There are many issues and challenges that effect routing of data. First, high energy is consumed which reduces network lifetime. Second, security of routing path is another issue due to development in the cryptanalysis against nodes. The aim of this paper is to propose an energy aware routing approach that considers energy level for sensors during cluster heads and routing path selections. Performance, network efficiency and maximizing network lifetime are measured by simulation, analysis and comparison with other well-known mechanisms.

Routing traffic on the internet efficiently has become an important research topic over the past decade. In this article we consider a generalization of the shortest path problem, the path-trading problem, which has applications in inter-domain traffic routing. When traffic is forwarded between autonomous systems (ASes), such as competing internet providers, each AS selfishly routes the traffic inside its own network. Efficient solutions to the path trading problem can lead to higher global performance in such systems, while maintaining the objectives and costs of the individual ASes. First, we extend a previous hardness result for the path trading problem. Moreover, we provide an algorithm that finds all Pareto-optimal path trades for a pair of two ASes. While in principal the number of Pareto-optimal path trades can be exponential, in our experiments this number was typically small. We use the framework of smoothed analysis to give a theoretical explanation for that fact. The computational results show that our algorithm yields far superior running times and can solve considerably larger instances than a previously known algorithm.

The scale-free topology of power communication network leads to more data flow in less hub nodes, which can cause local congestion. Considering the differences of the nodes’ delivery capacity and cache capacity, an integrated routing based on the communication service classification is proposed to reduce network congestion. In the power communication network, packets can be classified as key operational services (I-level) and affairs management services (II-level). The shortest routing, which selects the path of the least hops, is adopted to transmit I-level packets. The load-balanced global dynamic routing, which uses the node’s queue length and delivery capacity to establish the cost function and chooses the path with minimal cost, is adopted to transmit II-level packets. The simulation results show that the integrated routing has a larger critical packet generation rate and can effectively reduce congestion.

International audience; In this paper, we propose SR3 (which means Secure Resilient Reputation-based Routing), a secure and resilient algorithm for convergecast routing in WSNs (Wireless Sensor Networks). SR3 uses lightweight cryptographic primitives to achieve data confidentiality and unforgeability. Security of SR3 has been proven formally using two verification tools: CryptoVerif and Scyther. We made simulations to show the resiliency of SR3 against various scenarios, where we mixed selective forwarding, blackhole, wormhole, and Sybil attacks. We compared our solution to several routing algorithms of the literature. Our results show that the resiliency accomplished by SR3 is drastically better than the one achieved by those protocols, especially when the network is sparse. Moreover, unlike previous solutions , SR3 self-adapts after compromised nodes suddenly change their behavior.

Routing in cognitive radio ad hoc networks (CRAHNs) is a daunting task owing to dynamic topology, intermittent connectivity, spectrum heterogeneity, and energy constraints. Other prominent aspects such as channel stability, path reliability, and route discovery frequency should also be exploited. Several routing protocols have been proposed for CRAHNs in the literature. By stressing on one of the aspects more than any other, however, they do not satisfy all requirements of throughput, energy efficiency, and robustness. In this paper, we propose an energy-efficient and robust multipath routing (ERMR) protocol for CRAHNs by considering all prominent aspects including residual energy and channel stability in design. Even when the current routing path fails, the alternative routing path is immediately utilized. In establishing primary and alternative routing paths, both residual energy and channel stability are exploited simultaneously. Our simulation study shows that the proposed ERMR outperforms the conventional protocol in terms of network throughput, packet delivery ratio, energy consumption, and end-to-end delay.

International audience; In this paper, we address the problem of QoS support in an heterogeneous multi-rate wireless mesh network. We propose a new routing metric that provides information about link quality, based on PHY and MAC characteristics, including the link availability, the loss rate and the available bandwidth. This metric allows to apprehend inter-flow interferences and avoid bottleneck formation by balancing traffic load on the links. Based on the conflict graph model and calculation of maximal cliques, we define a method to estimate the available bandwidth of a path which considers, in addition, intra-flow interferences. Finally, we propose a routing protocol that supports this metric and we study by simulation its performances compared to different existing routing metrics and protocols. The results revealed the ability of our protocol (LARM) to support the network scalability as well as its ability to choose routes with high throughput and limited delay, thus, better delivery of data traffic.

International audience; In recent years, there have been significant efforts to standardize a routing protocol for Low-power and Lossy Networks (LLNs). This effort has culminated in standard IPv6 routing protocol for LLNs (RPL). The main interest of RPL is to improve routing in a LLN minimizing the usage of network resources. For this, RPL build acyclic graphs and applies an Objective Function (OF) which is responsible of choosing the preferred parent and the best links during the construction of the Destination Oriented Directed Acyclic Graph (DODAG). This paper introduces a new OF, based on a Non-Linear Length (NL-OF) which takes into account any number of metrics and constraints for QoS routing. NL-OF ensures that each path in the DODGA respects the input constraints. The NL-OF can be used to meet the requirements of sensible applications, such as real-time applications. A significant part of this work aims at studying the theoretical of the NL-OF. Finally, using Cooja simulator, we evaluate the performance of NL-OF. We show that our new Objective Function gives a good result and outperforms the three existing OFs when considering three QoS parameters which are End-to-End Delay, Packet Loss and Jitter.

International audience; Vehicular ad hoc networks (VANETs) are characterized by frequent path failures due to the high mobility caused by the sudden changes of vehicles direction. The routing paths between two different vehicles should be established with this challenge in mind. It must be stable and well connected in order to guarantee a reliable and safe delivery of packets. The aim of this work is to present a new reactive routing technique providing effective and well-regulated communication paths. These discovered paths are created based on a robust flooding discovery process involving UAVs (Un-manned Aerial Vehicles) to ensure the connectivity when the network is sparsely connected. The evaluation of this technique is performed using NS-2 simulator and its performances are compared with on-demand protocols dedicated for VANET. Simulation results show clearly that our approach gives interesting outcomes ensuring a high delivery ratio with a minimum delay. This hybrid communication between the vehicles and UAVs is attractive to initiate more smart connected nodes in the near future.

International audience; Developing highly efficient routing protocols for Vehicular Ad hoc Networks (VANETs) is a challenging task mainly due to the special characters of such networks: large-scale sizes, frequent link disconnections and rapid topology changes. In this paper, we propose an adaptive quality of service (QoS) based routing for VANETs called AQRV. This new routing protocol is to adaptively choose the intersections through which data packets pass to reach the destination, and the selected route should satisfy with the QoS constraints and fulfill the best QoS in terms of three metrics, namely connectivity probability, packet delivery ratio and delay. To achieve the above objectives, we mathematically formulate the routing selection issue as a constrained optimization problem, and propose an Ant Colony Optimization (ACO) based algorithm to solve this problem. In addition, a terminal intersection concept is presented to decrease routing exploration time and alleviate network congestion. Moreover, in order to decrease network overhead, we propose Local QoS Models (LQM) to estimate real-time and complete QoS of urban road segments. Simulation results validate our derived LQM models and show the effectiveness of AQRV.

International audience; Segment Routing (SR) architecture is a promising technology. It is being standardized in collaboration between vendors and service providers. Through its simplistic control plane and the reuse of existing data planes namely MPLS and IPv6, SR helps operators to reduce the Operation Expense (OpEx) and the Capital Expense (CapEx). In the instantiation of SR over the MPLS data plane (SR-MPLS), a SR path gets encoded as a label stack that the ingress nodes push onto the client packet. However, the longer the path in term of traversed nodes the bigger the stack gets. In this demonstration, we couple the capabilities of an SDN controller and a path encoding engine to reduce that size of the label stack to express segment routing paths.

International audience; In this paper we address the Swap-Body Vehicle Routing Problem, a variant of the Truck and Trailer Routing Problem. It was introduced in the VeRoLog Challenge 2014. We develop a solution approach that we coin Relax-and-Repair. It consists in solving a relaxed version of the SB-VRP and deriving a feasible solution by repairing the relaxed one. We embed this approach within a population-based heuristic. During computation we store all feasible routes in order to derive better solutions by solving a set-partitioning problem. In order to take advantages of nowadays multi-core machines, our algorithm is designed as a collaborative parallel population-based heuristic. Experimental results show that our relax-and-repair algorithm is very competitive and point the impact of each phase on the quality of the obtained solutions. The advantage of our approach is that it can be adapted to solve complex industrial routing problems.

The end-to-end throughput of a routing path in wireless multihop network is restricted by a bottleneck node that has the smallest bandwidth among the nodes on the routing path. In this study, we propose a method for resolving the bottleneck-node problem in multihop networks, which is based on multihop DESYNC (MH-DESYNC) algorithm that is a bioinspired resource allocation method developed for use in multihop environments and enables fair resource allocation among nearby (up to two hops) neighbors. Based on MH-DESYNC, we newly propose weighted-DESYNC (W-DESYNC) as a tool artificially to control the amount of resource allocated to the specific user and thus to achieve throughput fairness over a routing path. Proposed W-DESYNC employs the weight factor of a link to determine the amount of bandwidth allocated to a node. By letting the weight factor be the link quality of a routing path and making it the same across a routing path via Cucker-Smale flocking model, we can obtain throughput fairness over a routing path. The simulation results show that the proposed algorithm achieves throughput fairness over a routing path and can increase total end-to-end throughput in wireless multihop networks.

Recent standardization efforts are consolidating the role of routing protocol for low-power and lossy networks (RPL) as the standard routing protocol for IPv6-based wireless sensor and actuator networks. Investigating possible attacks against RPL is a top priority to improve the security of the future Internet of Things systems. In this letter, we present the DIO suppression attack , a novel degradation-of-service attack against RPL. Unlike other attacks in the literature, the DIO suppression attack does not require to steal cryptographic keys from some legitimate node. We show that the attack severely degrades the routing service, and it is far less energy-expensive than a jamming attack.

IPv6 Segment Routing is a major IPv6 extension that provides a modern version of source routing that is currently being developed within the Internet Engineering Task Force (IETF). We propose the first open-source implementation of IPv6 Segment Routing in the Linux kernel. We first describe it in details and explain how it can be used on both endhosts and routers. We then evaluate and compare its performance with plain IPv6 packet forwarding in a lab environment. Our measurements indicate that the performance penalty of inserting IPv6 Segment Routing Headers or encapsulating packets is limited to less than 15\%. On the other hand, the optional HMAC security feature of IPv6 Segment Routing is costly in a pure software implementation. Since our implementation has been included in the official Linux 4.10 kernel, we expect that it will be extended by other researchers for new use cases.

In this paper we aim at rendering a wireless networked control system robust with respect to packet losses exploiting routing redundancy. More precisely, we send multiple copies of sensing and actuation data via different routing paths, associated to possibly different delays and packet loss probability, and assume that such data can be re-combined as a weighted linear combination. We extend previous results from the SISO state-feedback to the MIMO output-feedback architecture and provide a methodology to design such weights either to maximize or to constrain a robustness metric based on the notion of Asymptotic Mean Square Stability. Such a metric induces an objective or constraint function that is highly non-linear: we propose a more efficient sub-optimal design methodology that takes into account both the network parameters and the plant dynamics.

International audience; In networks that operate during a long time, the routing protocol might have to be changed: this is the case when the network administrator plans a router change. Loop-free transition algorithms are used to ensure that there is no loop during the migration from the initial routing protocol to the final routing protocol. In this paper, we propose a distributed loop-free transition algorithm, called DLF (distributed loop-free heuristic). The algorithm is based on the fact that routing loops resulting from the removal of a node are localized, and can be detected efficiently. We show through simulations that DLF compares well with the existing centralized algorithms, and outperforms the existing distributed algorithm, in terms of migration duration.

The progressive miniaturization of technology and the unequal scalability of the BEOL and FEOL layers aggravate the routing congestion problem and have a negative impact on manufacturability. Standard cells are designed in a way that they can be treated as black boxes during physical design. However, this abstraction often prevents an efficient use of its internal free resources. This paper proposes an effective approach for using internal routing resources without sacrificing modularity. By using cell generation tools for regular layouts, libraries are enriched with cell instances that have lateral pins and allow under-the-cell connections between adjacent cells, thus reducing pin count, via count and routing congestion. An approach to generate cells with regular layouts and lateral pins is proposed. Additionally, algorithms to maximize the impact of under-the-cell routing are presented. The proposed techniques are integrated in an industrial design flow. Experimental results show a significant reduction of design rule check violations with negligible impact on timing.

[EN] Routing is a key design parameter in the interconnection network of large parallel computers. Routing algorithms are classified into two different categories depending on the number of routing options available for each source-destination pair: deterministic (there is one path available) and adaptive (there are several ones). Adaptive routing has two opposed effects on network performance. On one hand, it provides routing flexibility that may help on avoiding a congested network area, thus improving network performance. On the other hand, it also may increase the Head-of-Line blocking effect due to more destination nodes sharing the port queues. Usually, adaptive routing uses virtual channels to provide routing flexibility and to guarantee deadlock freedom. Deterministic routing is simpler, which implies lower routing delay and it introduces less Head-of-Line blocking effect. In this paper, we propose an adaptive and HoL-blocking reduction routing algorithm for direct topologies that tries to combine the good properties of both worlds: It provides routing flexibility but also reduces the Head-of-Line blocking effect. To do that, this paper proposes several functions which use the XOR operation to efficiently distribute the packets among virtual channels based on their destination node. The resulting routing mechanisms have different properties depending on whether they enforce routing flexibility or Head-of-Line blocking reduction., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO) and by FEDER funds under Grant TIN2015-66972-05-1-R and by Programa de Ayudas de Investigacion y Desarrollo (PAID) from Universitat Politecnica de Valencia.

International audience; Over recent years, green communications have been proposed as an emerging strategy to reduce the Carbon footprint produced by the networking sector. It consists in using different software and hardware techniques allowing to minimize the energy consumption of network components. A significant amount of energy saving can be obtained by switching redundant or unused network components to inactive mode, referred to as sleep-scheduling. To achieve this, the routing algorithm should aggregate traffic flows over a subset of network routers and their links, allowing other components to be switched off. The objective of this paper is to present a holistic survey on existing sleep-scheduling based green routing protocols in wired networks. First, we propose a classification of main properties of sleep-scheduling based green routing protocols and use the proposed classification to categorize and describe the existing literature. Moreover, we provide a comprehensive comparison of existing green routing protocols and determine the main characteristics, assets and issues of each proposal. In addition, we identify and classify the main metrics for evaluating and comparing the efficiency of green routing protocols using sleep-scheduling. Finally, we identify the open issues and key guidelines towards an ideal green routing protocol for wired networks.

The main objective of this paper is to investigate the effects of routing protocols on wireless sensor and actuator networks (WSANs), focusing on the control system response and the energy consumption of nodes in a network. We demonstrate that routing algorithms designed without considering the relationship between communication and control cannot be appropriately used in wireless networked control applications. For this purpose, an ad-hoc on-demand distance vector (AODV) routing, an IEEE 802.15.4, and a building-temperature control system are employed for this exploration. The findings from our scenarios show that the AODV routing can select a path with a high traffic load for data transmission. It takes a long time before deciding to change a new route although it experiences the unsuccessful transmission of packets. As a result, the desirable control target cannot be achieved in time, and nodes consume more energy due to frequent packet collisions and retransmissions. Consequently, we propose a simple routing solution to alleviate these research problems by modifying the original AODV routing protocol. The delay-threshold is considered to avoid any congested connection during routing procedures. The simulation results demonstrate that our solution can be appropriately applied in WSANs. Both the energy consumption and the control system response are improved.

International audience; This article deals with a particular class of routing problem, consisting of the planning and routing of technicians in the eld. This problem has been identi ed as a multiperiod, multidepot uncapacitated vehicle routing problem with speci c constraints that we call the Multiperiod Field Service Routing Problem (MPFSRP). We propose a set covering formulation of the problem for the column generation technique and we develop an exact branch and price solution method for small-sized instances. We also propose several heuristic versions for larger instances. We present the results of experiments on realistic data adapted from an industrial application.

Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well.

Software-Defined Networking (SDN) is a recent model of networking architecture which splits the network control from data forwarding functions. Most SDN solutions have in their scope the wired networks, but more recently, some attempts have been made to adapt SDN architecture for the context of wireless mesh networks (WMNs). In the present paper, we examine whether the use of the SDN paradigm in WMNs can help overcome certain limitations of the classic routing algorithms. To that end, we propose a new deployment architecture which exploits the main benefits of this paradigm: faster routing convergence and optimal path identification and takes advantage of multiple communication interfaces that most wireless devices already possess to split the signalling and data transfer. We then propose an hybrid management scheme applicable which mixes our SDN approach with a conventional distributed protocol (OLSR in our case). Through NS3 simulations, an improvement of 20% in both packet delivery ratio and lost packets was observed. Therefore, we can claim that the SDN controller can positively assist the distributed routing protocol operations.

In this paper we study a revenue maximization problem for optical routing nodes. We model the routing node as a single server polling model with the aim to assign visit periods (service windows) to the different stations (ports) such that the mean profit per cycle is maximized. Under reasonable assumptions regarding retrial and dropping probabilities of packets the optimization problem becomes a separable concave resource allocation problem, which can be solved using existing algorithms., Key Words- optical routing, optical node, revenue, optimization

Competitive routing across peering links is a notable problem in Internet routing. A few years ago, a proposal to incrementally modify the Border Gateway Protocol (BGP) decision process was done, to improve routing coordination by leveraging on the existing multi-exit discriminator BGP attribute as signaling medium among peering Internet networks. It is called Peering Equilibrium Multipath (PEMP) routing: based on a non-cooperative potential game, it can improve routing stability and efficiency while respecting unilateral routing choice, by supporting strategic multipath forwarding decisions. The contribution of this paper is twofold. First, we specify how weighted load-balancing should be done in PEMP routing and examine the benefits against even load-balancing. Then we document an implementation of PEMP routing in the Quagga open source router, better specifying some aspects. We provide a performance evaluation of the implemented PEMP routing system, showing that the computing overhead is limited.

In a multihop wireless network, such as a wireless sensor network (WSN), with nodes being aware of their locations, the geographic routing scheme is an effective way of delivering packets to their destinations because of its 1-hop beacon broadcasting based routing related information exchange operation. The routing information obtained via 1-hop beaconing is local in the sense that it is just 1-hop compared to the multihop end-to-end routing. Hence, at some point, packets may experience no more place to be forwarded to (i.e., dead-ends). In this paper, we propose a geographical routing mechanism adopting the concept of the azimuth to reduce the possibility of packets confronting dead-ends. In other words, the node with a packet to be forwarded to the final destination figures out the next-hop node by utilizing the azimuth of the destination as a routing metric. Besides, we propose additional routing metrics for stable next-hop node selection to provide reliable IP connectivity. In order to validate the performance of the proposed routing mechanism, we evaluate its performance through the NS-2 based simulations and show that our mechanism outperforms the other schemes in terms of the packet delivery success rate, the end-to-end delay, and the number of dead-end encounters.

This paper presents a study of a method termed, multi-plane routing, that maximizes path diversity in IP routing and is targeted for IP access networks (AN). The motivation for the work is in the specific shortcomings of the conventional intra-domain IP routing principles such as “shortest-path” and “best-effort” when applied in IP ANs. We generalize these networks as the transit between the access routers and gateway and they range from a simple tree to meshed tree topologies. The method uses Multi-Topology OSPF standardized by the IETF and instantiates multiple OSPF installations in networks, each installation utilizing a portion of the topology in the conventional manner, i.e. routing plane (RP). Hence, all links are utilized by having at least one standard OSPF routing installation including them in the paths between access router and gateway. The method functions on extensions in routers and simple packet tagging allowing the routers to install and separate between paths of each RP. Routing is facilitated by the proposed method’s algorithms for network planning and traffic engineering. The former is called the offline algorithm rendering the optimum number of RPs in an arbitrary topology by independently setting link weights for each plane. The latter is called the online algorithm that applies a policy-based routing scheme for dynamically selecting the best RP based on the introduced QoS-aware cost function. The paper concludes by significant improvements in throughput, packet loss rate, session blocking and delays for numerous cases of topologies differing in numbers of networks nodes and degrees of meshing.

Increasing network lifetime by reducing energy consumption across the network is one of the major concerns while designing routing protocols for Mobile Ad-Hoc Networks. In this paper, we investigate the main reasons that lead to energy depletion and we introduce appropriate routing metrics in the routing decision scheme to mitigate their effect and increase the network lifetime. For our routing scheme, we take into consideration multiple layer parameters, such as MAC queue utilization, node degree and residual energy. We integrate our multi-metric routing scheme into OLSR, a standard MANET proactive routing protocol. We evaluate via simulations in NS3 the protocol modifications under a range of different static and mobile scenarios. The main observations are that in static and low mobility scenarios our modified routing protocol leads to a significant increase (5\%-20\%) in network lifetime compared to standard OLSR and slightly better performance in terms of Packet Delivery Ratio (PDR)., 6 pages, Appeared in IEEE MILCOM 2014

This paper studies the problem of robust spectrum-aware routing in a multi-hop, multi-channel Cognitive Radio Network (CRN) with the presence of malicious nodes in the secondary network. The proposed routing scheme models the interaction among the Secondary Users (SUs) as a stochastic game. By allowing the backward propagation of the path utility information from the next-hop nodes, the stochastic routing game is decomposed into a series of stage games. The best-response policies are learned through the process of smooth fictitious play, which is guaranteed to converge without flooding of the information about the local utilities and behaviors. To address the problem of mixed insider attacks with both routing-toward-primary and sink-hole attacks, the trustworthiness of the neighbor nodes is evaluated through a multi-arm bandit process for each SU. The simulation results show that the proposed routing algorithm is able to enforce the cooperation of the malicious SUs and reduce the negative impact of the attacks on the routing selection process., Submitted to IEEE Transactions on Wireless Communications

We present CCN-DART, a more efficient forwarding approach for content-centric networking (CCN) than named data networking (NDN) that substitutes Pending Interest Tables (PIT) with Data Answer Routing Tables (DART) and uses a novel approach to eliminate forwarding loops. The forwarding state required at each router using CCN-DART consists of segments of the routes between consumers and content providers that traverse a content router, rather than the Interests that the router forwards towards content providers. Accordingly, the size of a DART is proportional to the number of routes used by Interests traversing a router, rather than the number of Interests traversing a router. We show that CCN-DART avoids forwarding loops by comparing distances to name prefixes reported by neighbors, even when routing loops exist. Results of simulation experiments comparing CCN-DART with NDN using the ndnSIM simulation tool show that CCN-DART incurs 10 to 20 times less storage overhead.

International audience; In networks that operate during a long time, the routing protocol might have to be changed (in order to apply a routing protocol update, or to take into account a change in the routing metrics). A loop-free transition algorithm has to be used in order to perform the transition to the new routing protocol without generating transient routing loops. In this paper, we propose a loop-free transition algorithm called ACH (avoiding cycles heuristic), which is able to perform the transition in a very small number of steps. Compared to other algorithms of the literature, ACH yields a number of steps which is independent of both the number of nodes and the number of destinations, and thus allows the transition to be performed in a small time. We show through simulations that ACH significantly outperforms other heuristics of the literature, due to its capability to deal with several destinations at once, and due to a priority-based procedure to avoid cycles.

Wireless sensor networks frequently use multi-path routing schemes between nodes and a base station. Multi-path routing confers additional robustness against link failure, but in battery-powered networks it is desirable to choose paths which maximise the overall network lifetime - the time at which a battery is first exhausted. We introduce multi-objective evolutionary algorithms to find the routings which approximate the optimal trade-off between network lifetime and robustness. A novel measure of network robustness, the fragility, is introduced. We show that the distribution of traffic between paths in a given multi-path scheme that optimises lifetime or fragility may be found by solving the appropriate linear program. A multi-objective evolutionary algorithm is used to solve the combinatorial optimisation problem of choosing routings and traffic distributions that give the optimal trade-off between network lifetime and robustness. Efficiency is achieved by pruning the search space using k-shortest paths, braided and edge disjoint paths. The method is demonstrated on synthetic networks and a real network deployed at the Victoria & Albert Museum, London. For these networks, using only two paths per node, we locate routings with lifetimes within 3% of those obtained with unlimited paths per node. In addition, routings which halve the network fragility are located. We also show that the evolutionary multi-path routing can achieve significant improvement in performance over a braided multi-path scheme.

The proliferation of new online Internet services has substantially increased the energy consumption in wired networks, which has become a critical issue for Internet Service Providers. In this paper, we target the network-wide, energy-saving problem by leveraging speed scaling as the energy-saving strategy. We propose a distributed routing scheme –HDEER– to improve network energy efficiency in a distributed manner without significantly compromising traffic delay. HDEER is a two-stage routing scheme where a simple distributed multi-path finding algorithm is firstly performed to guarantee loop-free routing, and then a distributed routing algorithm is executed for energy-efficient routing in each node among the multiple loop-free paths. We conduct extensive experiments on the NS3 simulator and simulations with real network topologies in different scales under different traffic scenarios. Experiment results show that HDEER can reduce network energy consumption with a fair tradeoff between network energy consumption and traffic delay. pub