Low-Power and Lossy Wireless Networks (LLWNs) operate under stringent energy, memory, and bandwidth constraints and rely on inherently unreliable multi-hop links. Despite substantial progress in IoT networking, updating deployed LLWNs often still requires bulky, full-image firmware upgrades, even for minor network stack changes. This practice incurs excessive overhead, complicates reliable delivery over lossy links, and can temporarily disrupt connectivity due to mandatory reboots. We introduce FINE-STACK, a flexible architecture that decomposes the network stack into lightweight virtual functions coordinated by a central orchestrator. By enabling fine-grained composition and semantics-aware management of protocol components, FINE-STACK supports fast and selective over-the-air updates at runtime. It further improves the programmability of the network stack by enabling hybrid deployments that combine local in-network control with optional global optimization. We implemented and evaluated FINE-STACK on a real-world testbed, comparing programmability and performance across conventional deployment models and the hybrid model enabled by our design. The results demonstrate that hybrid deployments provide improved programmability and superior operational performance, while fine-grained modularity of the network stack substantially reduces update size and update time without violating strict memory, power and overhead constraints. Overall, FINE-STACK advances LLWNs toward practical network programmability, narrowing the gap between flexibility and efficiency, and making semantic runtime reconfiguration feasible on highly constrained IoT devices.

Synchronized MAC protocols are now considered as the ultimate solution to access the medium in wireless sensor networks. They guarantee both high throughout and constant latency and achieve reasonable energy consumption performance. However, synchronization is achieved at the cost of a complex framework with low flexibility on its parameters that is not suitable for some network topologies or application requirements. By contrast, asynchronous MAC protocols are versatile by nature but suffer from the tradeoff between energy consumption and latency. However, the addition of Wake-up Radio (WuR) can reduce the energy consumption of such protocols while maintaining very low latency thanks to its always-on feature and ultra-low power consumption. In this article, we present WuR-based Multi-hop Multi-channel (W2M), an asynchronous MAC protocol for wireless sensor networks. We also provide a fair comparison with Time Synchronized Channel Hopping (TSCH) through an extensive simulation campaign based on Contiki-NG and Cooja. Our results show that in low traffic scenarios, W2M outperforms TSCH in reducing both the energy consumption and the latency (at least 68% of energy is saved), but at the cost of slightly lower reliability.

The devices of Internet of Things (IoT) networks can be deployed for extended period of time in inaccessible locations. After their deployment, new features, bug fixes, or changes in the client needs can require an update of the node's behavior, and this update has to be transmitted over the radio medium. Proposals have been made in the literature to apply the Software Defined Network (SDN) paradigm to wireless sensor networks but they focus on the packet forwarding layer of the stack. In this work, we propose to extend the programmability to the whole stack with a fully programmable device architecture able to handle the runtime programming of every protocol on any hardware. We detail the use of extended finite-state machines (XFSM) on which the architecture is based and their conversion to compact executable bytecode that can be sent over radio. Simulations demonstrate that this architecture can reproduce a protocol from the literature and enable interoperability between programmable nodes and legacy nodes.

The growing importance of the data in today’s applications, such as machine learning, makes merchandising them more appealing, but it opens various challenges. Indeed, we want data to be delivered in a fast, reliable, and secure manner. This means we want guarantees about the payment and the correct delivery of the data, while still offering the ease of existing publish/subscribe protocols. There exists no state-of-the-art protocol that answers to all those challenges. Most of them lack the security properties needed for merchandising data and the few secured propositions do not scale well with the number of buyers, which prevents them from global use. In this paper, we present a data payment system based on SUPRA, a publish/subscribe protocol having delivery guarantees. With our solution, it is possible to securely sell data while sharing them using the publish/subscribe model, which is known for its scalability in one-to-many communications. After presenting how our system works, we explain how it answers the various challenges of merchandising data and compare it to the other state-of-the-art solutions.

Wake-Up Radios is an emerging technology, aiming at pushing forward the frontiers of energy efficiency without trading it off for latency nor reliability. Extending the lifetime of the nodes as much as possible is one of the main goals in Multi-hop Wireless Sensor Networks. The Routing Protocol for Low Power and Lossy Networks (RPL) is commonly used in these applications. However, there is still an open problem in its design when it comes to achieving both stability and efficient routing at the same time. In this article, we present Load Balancing Parent Selection (LoBaPS), an algorithm to select opportunistically the next hop, based on RPL. It capitalizes on the Wake-Up Radio and its always-on feature, as well as its Ultra-Low Power consumption. We compare the performance of LoBaPS with that of W-MAC, a reference protocol that uses Wake-Up Radio and supports RPL in its traditional way. The results are obtained through simulations in COOJA for a network of nodes running ContikiOS, and show that the lifetime can be improved up to 55%, while the Packet Delivery Ratio (PDR) can raise a maximum of 20%, keeping a reasonable level of latency. In addition, the network is more robust to node shutdowns and requires less control overhead.

In Wireless Sensor Networks (WSN), duty-cycled Medium Access Control (MAC) protocols trade off latency for energy efficient operation. Over the past few years, Wake-Up Radio (WuR) has been presented as the ultimate solution for this tradeoff, allowing to reduce both at the same time. However, this might not be the general case regarding the large range of network configurations used in WSN. Several previous works have been done comparing WuR to traditional duty-cycled solutions, but no one has investigated before the limitations of this technology. In this article, we analyze the benefits and drawbacks of using WuR in multi-hop WSN. We also identify black spots in WuR that have not been investigated yet. Our study is based on evaluations using COOJA, a simulator for networks of ContikiOS nodes. A traditional duty-cycled MAC protocol is also included in our study for comparative purposes. From our study, we quantify the performances of WuR and provide some guidelines on how this technology can be efficiently used in multi-hop wireless sensor networks.

Recent boom of mobile applications has become an essential class of mobile Internet of Things (IoT), whereby large amounts of sensed data are collected and shared by mobile sensing devices for observing phenomena such as traffic or the environmental. Currently, most of the proposed Medium Access Control (MAC) protocols mainly focus on static networks. However, mobile sensor nodes may pose many communication challenges during the design and development of a MAC protocol. These difficulties first require an efficient connection establishment between a mobile and static node, and then an efficient data packet transmissions. In this study, we propose MobIQ, an advanced mobility-handling MAC scheme for low-power MAC protocols, which achieves for efficient neighbour(hood) discovery and low-delay communication. Our thorough performance evaluation, conducted on top of Contiki OS, shows that MobIQ outperforms state-of-the-art solutions such as MoX-MAC, MOBINET and ME-ContikiMAC, in terms of significantly reducing delay, contention to the medium and energy consumption.

The last decade saw the emergence of the Internet of Things (IoT) paradigm, which aims to connect any object to the Internet. In this context, a new type of wireless communication network emerged known as Low-Power Wire-Area Network (LPWAN). By contrast to well-known short range and multi-hop wireless networks, LPWAN networks allow long range communications at a low bit rate. Furthermore, LPWAN networks are considered to be integrated into 5G. Among LPWAN networks, the LoRaWAN technology gains more and more interest from the research and industrial communities. In this article, we have led a thorough experimental performance evaluation of LoRaWAN in an indoor environment. From this study, we quantify the limits of this technology and expose the merits of using LoRaWAN for IoT communications in the context of 5G.

The Internet of Things (IoT) is the first real evolution of the Internet, in contrast with the Web which has been evolving over time. IoT enables the crossing-over of the physical and cyber worlds by deploying sensor devices on a global scale. This crossing-over promises exciting applications that, thanks to intelligent ubiquitous services, will facilitate our daily life. However, the data that represent the bridge between the real and the digital worlds are endangered and their quality is uncertain. In fact, data are the base of insights mining which are used to make intelligent decisions and provide services. If the data are inaccurate, decisions are likely to be unsound. Data accuracy and trustworthiness are crucial to gain user engagement and acceptance of the IoT paradigm and services. This paper aims at enhancing data quality in the context of the Internet of Things by providing an overview of the state of the art of data quality in the context of IoT. Data outliers and their underlying knowledge are surveyed alongside their discovery and detection process. The outliers' impact in the context of IoT and its applications is identified. Techniques for data cleaning are reviewed and compared with respect to an extended taxonomy. Finally, open challenges and possible future research directions are discussed.

The devices composing Wireless Sensor Networks (WSN) are very limited in terms of memory, processing power and battery. RPL has emerged as the de facto routing standard in low-power and lossy networks. While most of the proposals focus on minimizing the global energy consumption, we aim here at designing an energy-balancing routing protocol: each node should efficiently consume the same quantity of energy to improve the network lifetime. To this end, we exploit an Expected Lifetime metric, denoting the residual time of the nodes (time until the node will run out of energy). We propose mechanisms to detect the energy-bottleneck nodes and to spread the traffic load uniformly among them. While RPL constructs a Destination-Oriented Directed Acyclic Graph (DODAG) structure, it only implements single path. We propose here to exploit its natural multipath structure. This multipath approach helps reducing the number of DODAG reconstructions that leads to instabilities and convergence problems. Simulations highlight we improve both the routing reliability and the network lifetime.

This demonstration aims at observing in an interactive manner the impact of modification of preamble and sampling periods at the low-power family of MAC protocols, and thus, illustrating in real-time the energy consumption and delay performance of each node accordingly. To do so, we implemented the ability for users to generate traffic at some remote nodes that are involved in two distinct deployed topologies. Those deployed networks operate with either a statically configured network, by employing X-MAC on top of the Contiki OS, or T-AAD, a lightweight traffic auto-adaptive protocol that allows live and automatic modifications of duty-cycle configurations.

In traditional routing protocols designed for Wireless Sensor Networks, each sensor node is related to one or more neighbors that will forward its readings up to the sink. This technique performs well for static topologies with homogeneous configurations, but usually fails to cope with network dynamics such as mobility and node failures. Opportunistic routing is an approach to address this particular problem. In this context, the data packets are addressed to a set of potential forwarders and then forwarded by the neighbor that first acknowledges the message. Yet, several former studies demonstrated that in some cases, a single packet may be forwarded by multiple neighbors simultaneously. This situation leads to packet duplication and consequently to increased channel occupancy and energy consumption in the network. In this paper, we study to what extent the previously reported phenomenon depends on both the topology density and the nodes MAC configuration. We then introduce a mechanism that handles the potential deafness in the network through heterogeneous configuration among the nodes in the network. We do so through local, dynamic and automatic MAC parameters adaptation, in order to reduce unnecessary traffic, channel occupancy and energy consumption due to packet duplication in opportunistic networks. Finally, we provide both theoretical analysis and experimental campaign to detail the benefits of our approach.

Wireless Sensor Networks (WSN) have become popular in the last years. Paths between sensors are computed by routing protocols, which are specifically designed to cope with the characteristics of WSN. Lately, the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) has been accepted as the Internet Engineering Task Force (IETF) standard for routing packets in WSN. However, this protocol does not pay particular attention to mobile nodes. Furthermore, mobility has been contemplated as a way to improve sensing coverage and connectivity in unattended WSN. In addition, WSN will account for an increasingly huge number of connections, from 1.9 billion devices today to 9 billion by 2018 among which most of them would be mobile (e.g. wearable devices). Using RPL to support the mobility of nodes is the main problem investigated in this article. We propose a new version of the trickle algorithm which allows mobile nodes to move seamlessly into a routing topology build by RPL together with limiting the signalling overhead. Our proposal is compared to two other schemes available in the literature. Results highlight that our proposal significantly reduces disconnection times and increases the packet delivery ratio while mitigating the extra control traffic.

Due to their physical constraints and deployment conditions, power management is a key issue in Wireless Sensor Networks. The radio component being the most responsible for energy wastage, controlling medium access is of prime importance in order to obtain desired network lifetime. Several existing mechanisms realize energy gains by alternating active and passive periods at the radio scale and most real WSN deployments implement static and homogeneous duty-cycling (i.e. invariant and identical for each node in the network). Although preventing any node isolation, such method fails to address the dynamics of the network efficiently. We propose a strategy to enable heterogeneous MAC duty-cycle configurations among nodes in the network. We aim at granting each node a specific sleep-depth, according to criteria specific to the deployment (e.g. applicative criteria, location in the routing structure). To implement this idea, sensor nodes are divided into disjoint subsets, each of them standing for a given duty-cycle configuration and leading to a network performance managed at its best (e.g. energy consumption, loss rate). We detail to what extent our approach preserves network connectivity with coherent heterogeneous duty-cycling, thus reaching a compromise between energy consumption and reactivity. The presented experimental campaign was led over the SensLAB testbed. It demonstrates that our solutions provide up to 61% energy saving, yet preserving the loss-rate below 10%, and guaranteeing the connectivity of the network.

The IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) is one of the emerging routing standards for multihop Wireless Sensor Networks (WSN). RPL is based on the construction of a Destination-Oriented Directed Acyclic Graph (DODAG), which offers a loop-free topology to route data packets. While several routing metrics have been proposed in the literature, it is unclear how they perform with RPL. In this paper, we analyze the impact of different PHY and MAC metrics on the stability and efficiency of RPL. We highlight the fact that realistic conditions lead to instabilities and oscillations in the routing structure. While minimizing the hop length leads to a stable but poor routing structure, more sophisticated link metrics such as ETX reflect more clearly the radio link quality but increase the number of DODAG reconfigurations. We also provided a detailed methodology to measure the DODAG stability and to implement efficiently each routing metric with RPL.

Validation of protocols and mechanisms is an essential step to the development of object networks in critical domains. Most papers still provide evaluation either obtained through theoretical analysis or simulations campaigns. Yet, simulators and formal models fail to precisely reproduce the unique specificities of the deployment environments those networks have to evolve in. Also, by putting no limits to code complexity and execution, those tools prevent users to apprehend the actual limits of WSN nodes and to propose realistic communication protocols and applications. In this paper, we highlight to what extent the addition of experimentations can significantly improve the value of performance evaluation campaigns. Along with the recent tendency to have algorithmic and protocol proposals facing real environments, it is questionable whether the so obtained results should be considered as scientific or empirical ones. In the former case, reproducibility, stability over time, topology management to cite a few, are a must have for testbeds and real deployments that are used. In the latter, the results should be viewed as a proof-of-concept only, far from independent of the used hardware and encountered conditions at the experimentation time but still critical from the development cycle standpoint. Through some experiments over the IoT-LAB testbed, we aim at demonstrating to what extent some of the simulation setup and conditions from reality could be emulated. We also provide insight on how to obtain the best out of it in a quick and efficient manner. We show that such testbeds would satisfy many expectations (e.g. scientific tool and proof-of-concept validator), thus minding and bridging some of the gaps between theory and practice in WSN. To this end, we here give an overview of available simulation tools, and guidelines on how to transpose simulation setups to the open large-scale IoT-LAB platform.

This paper presents a description of SensLAB(Very Large Scale Open Wireless Sensor Network Testbed) that has been developed and deployed in order to allow the evaluation through experimentations of scalable wireless sensor network protocols and applications. SensLAB’s main and most important goal is to offer an accurate open access multi-users scientific tool to support the design, the development tuning, and the experimentation of real large-scale sensor network applications. The SensLAB testbed is composed of 1024 nodes over 4 sites. Each site hosts 256 sensor nodes with specific characteristics in order to offer a wide spectrum of possibilities and heterogeneity. Within a given site, each one of the 256 nodes is able both to communicate via its radio interface to its neighbors and to be configured as a sink node to exchange data with any other ” sink node ”. The hardware and software architectures that allow to reserve, configure, deploy firmwares and gather experimental data and monitoring information are described. We also present demonstration examples to illustrate the use of the SensLAB testbed and encourage researchers to test and benchmark their applications/protocols on a large scale WSN testbed.

Wireless sensor networks (WSN) require pertinent and reliable data collection schemes in order to provide information about their deployment area. This article aims at detailing our contribution for message loss avoidance along prone-to-failure paths that monitoring reports would follow from sensors to sink stations. While many researchers have tackled this issue by focusing on particular layers of the embedded communication stack (e.g. medium access control or routing protocol), we propose an original layer-independent scheme. The key aspect of our solution is to create fake data sources that have acted as storage nodes during the failure of links leading to the sink station. Few control messages are required during our gradual recovery phase, thus maintaining a negligible overhead in terms of message complexity and energy consumption, and also resulting in much improved data delivery ratio.

The medium access control being the main source of energy wastage in wireless sensor networks, energy-efficiency is always kept in mind while designing the communication stack. Especially, versatile preamble-sampling MAC protocols emerged to offer a suitable solution over multiple deployment characteristics. For instance, some works have targeted burst transmissions while others have focused on long-term energy-efficiency for mostly sleeping wireless sensors. In this paper, we observe to what extent versatility applies to dynamic scenarios in which communications do not respect specific paradigms. We show that preamble-sampling protocols lack an optimal configuration for antagonist traffic patterns. We therefore introduce an auto-adaptive algorithm that can adjust its sampling period and preamble length. Our solution is based on a link-by-link negotiation in order to establish energy-efficient communications over certain paths toward the sink station. This mechanism, auto-adapting to the current network traffic, can be used in combination with various preamble-sampling MAC layers, and works for every traffic pattern, being especially energy-efficient during burst transmissions. We particularly studied its association with X-MAC, and observed that energy savings are not accomplished to the cost of reliability.

Although mobility management within a network of wireless sensors is a relatively new subject, we envision that a mobile sensor will move through different networks. However, it is very likely that the routing protocol supported in a visited network is different from the one supported by the mobile sensor. In a convergecast communication model, it would suffice for mobile sensors to broadcast its messages into the visited network to have them forwarded to the sink. Though, this can lead to duplication of messages and therefore increase the network traffic in the visited network. In this article, we propose Mobinet whose objective is to enable mobile sensors to detect surrounding sensors in the visited network through passive listening in order to select one of them to transmit messages. We particularly focus on the energy consumption of the mobile sensors and consequently introduce various listening processes to limit the extra energy consumption resulting from the detection of surrounding sensors. Mobinet has been evaluated by simulation. Simulation results show the benefits of Mobinet in terms of message delivery and a lower energy consumption through the listening processes. They also highlight guidelines for future research.

Abstract In the past few years, the concept of pervasive connectivity has become of crucial importance. New protocols have therefore been standardized to enable IPv6 mobility, such as the Network Mobility Basic Support (NEMO BS) protocol. This protocol is particularly suited for providing a global IPv6 connectivity in intelligent transportation systems. Yet, despite its popularity and maturity, it still suffers from various limitations which prevent its adoption in large‐scale commercial deployments. Among these are operator specific issues such as the lack of practical and efficient bootstrapping procedure. Also, a global connectivity enables the provision of value‐added services whose attractiveness mainly depends on their ease of configuration. In this paper, we focus on solutions to address both the bootstrapping of NEMO BS and service discovery in a mobile environment. By investigating various bootstrapping proposals, we advocate the use of a standardized solution extended with the missing pieces to operate in a NEMO BS environment. We also expose how operator services could be exported and announced in the mobile subnet. Authentication and authorization to access these services are also investigated. Experiments on a prototype show that our proposal brings the missing blocks towards the deployment of network mobility service in intelligent transportation systems. Copyright © 2009 John Wiley & Sons, Ltd.

The main goal of Cluster-based sensor networks is to decrease system delay and reduce energy consumption. LEACH is a cluster-based protocol for micro sensor networks which achieves energy-efficient, scalable routing and fair media access for sensor nodes. However, the election of a malicious or compromised sensor node as the cluster head is one the most significant breaches in cluster-based wireless sensor networks. We propose a deterministic key management scheme, called DKS-LEACH, to secure LEACH protocol against malicious attacks. Our contributions are twofold. Firstly, we design and performed a theoretical evaluation of our security model which secures the setup and study phases of LEACH protocol. Secondly, using the TOSSIM simulator, we performed an evaluation of the power consumption of DKS-LEACH. The results indicate clear advantages of our approach in preventing the election of untrustworthy cluster head as well different kind of attacks from malicious sensor nodes.

The Layered Mobility Model Architecture (LEMMA) stipulates that a mobility model can be divided into five distinct layers, which communicate unidirectionally via simple interlayer interfaces. It has been shown that this general framework can be used for the creation of empirical and theoretical models, and that any mobility model can be represented by the form specified by LEMMA. The fundamental result of this paper is the definition and the proof of several theorems related to the stationarity of probabilistic mobility models specified under the form defined by LEMMA. We support our findings with the help of simulation, by performing simulations with 300 different mobility models over a range of nine network setups.

In this paper, we briefly describe an interactive roulette game enabled over a wireless sensor network platform. It basically consists in a train speeding in one way (the spinning roulette) and in a message hopping along some deployed sensors in the other way (the wheeling ball). This demonstration aims at illustrating in an interactive manner the high radio channel randomness in dense wireless sensor networks, as well as its impact on the communication protocols.

Wireless sensor networks operate in constrained environments. In addition to the limitations in terms of energy, memory and computation, the use of mobile sensors has recently been contemplated. However, only a few medium access control protocols consider the dynamic of such scenarios. In this paper, we present potential problems that could arise with nowadays protocols operating in mobile environments. We particularly focus on the synchronization issues between fixed and mobile sensors, as well as congestion in dense networks. For that purpose, we introduce Machiavel, a new method to access the medium. Machiavel allows mobile sensors to capture the channel even in networks with high contention, while guaranteeing the synchronization with their peers. An evaluation by simulation demonstrates the benefits of our contribution compared to the B-MAC protocol.

The layered mobility model architecture, as introduced earlier, provides a framework for the construction of microscopic mobility models for wireless network simulations. In this paper, we are continuing our study of the architecture and provide the fundamental results necessary for the definition and analysis of theoretic models. This is done for the first time for such rich mobility framework, allowing the definition of layers both based on empirical and theoretical grounds. A formal definition of a mobility model is given, applicable in a very broad range of cases. We define explicitly the mathematical entities corresponding to the different layers both for deterministic and probabilistic models. Finally, we provide the necessary proofs that any mobility model may be represented under the form specified by LEMMA.

The Network Mobility Basic Support (NEMO BS) protocol is the IETF standard to manage the mobility of entire IPv6 networks. One of the typical applications of this protocol is to deploy NEMO BS in transportations such as train or bus. As a result, passengers can benefit from global and permanent IPv6 connectivity with legacy IPv6 terminals equipped with a common wireless technology such as Wi-Fi. However, a mobile network is generally managed by a single mobile router which carries out all operations related to mobility and packet forwarding. In this article, we present a new proposal which enables the cooperation of multiple mobile routers to improve the bandwidth, network coverage and reliability of a mobile network. In addition, a dynamic load sharing mechanism between all available mobile routers is supported. This solution mainly relies on Neighbor Discovery and has been experimented on a real testbed.

The mobile IPv6 protocol is becoming one of the most common ways to support IPv6 mobility. Yet, despite its popularity the protocol still suffers various limitations which prevent it from being adopted in large scale commercial deployments. Among these is the protocol's poor support (or lack thereof) for rapid and seamless handovers. When moving from one subnet to another, a mobile node may experience connection and/or packet loss which may introduce noise and cuts in real-time media streams delivered to the user. Many different solutions to this problem have been presented and evaluated in various papers during the last few years but none of them have so far been selected as the standard mobile IPv6 handover optimization. In this article an experimental analysis of two optimization schemes were presented and compared their performance to that of a standard mobile IPv6 implementation. One of them, the fast handovers mobile IPv6 protocol (FMIPv6) is being strongly supported by IETF working groups and is probably the one that, among all other handover optimization schemes, has most approached standardization. The GPS handovers solution, on the other hand seems to be one of the few that have the maturity and completeness of the FMIPv6 protocol, and in the same time resolves problems that seem to be unaddressed by FMIPv6. All analysis in this paper is based upon experimentation which the authors believed is superior to simulation or emulation when dealing with a subject that is so heavily influenced by the implementation specifics of the accompanying technologies. Mobile nodes in all experiments are communicating via the IEEE 802.11 WLAN technology. All experiments are conducted with unmodified versions of popular conferencing and streaming applications Gnomemeeting and VLC.

Straightforward, transparent mobility management has now been available for some time with IPv6 through the mobile IPv6 protocol. There are numerous MIPv6 implementations available and some have been successfully deployed and tested in real world scenarios. Yet, certain aspects of that mobility support, such as security, seamless handovers, and heterogeneous network technologies support are still being discussed and improved by working groups on the IETF and in various research communities. One such example is the continuing work on the "fast handovers for mobile IPv6" protocol that aims to reduce the packet loss and latency inherent to the handover process. In this document we present a set of experiments with an implementation of that protocol and the resulting performance evaluation. All tests take place over IEEE wireless LANs, and are performed using the fmipv6.org protocol implementation for the Linux operating system, that we have developed and contributed to the open source community. The paper, exposes an analysis of the provided results and brings out some issues, not currently addressed by the protocol, like for example connection and packet loss occurring during the IEEE 802.11 scanning procedure, and lack of more appropriate alternative mechanisms for discovery and selection of candidate access points. The purpose of the document is to provide evaluation material based on a link layer protocol that is (to our understanding) among the primary link layer protocols that FMIPv6 was built to work on. We find such an evaluation quite necessary for the pending optimisations of the protocol

IEEE 802.11 networks are now very common and are present in various locations. While roaming through access points, a mobile node is often required to perform a link layer handover. This mechanism causes user-interceptable connection loss and breaks in time-sensitive communication, especially if a network layer handover follows the link layer handover. Many solutions attempting to improve this process have been proposed but only a few use geolocation systems in the management of the handover. In this article, we present a new method to enhance both link layer and network layer handovers using geolocation information provided by a GPS system. The idea behind our algorithm is to predict the next mobile node point of attachment and the associated sub-network using the position of the mobile nodes. This method has been implemented using the new Mobile IP daemon for GNU/Linux operating system and evaluated through two scenarios

Abstract This paper proposes a solution framework for Mobile IPv6 to anticipate movement over IEEE 802.11 networks. Layer 2 triggers such as the signal strength is used to trigger in advance scanning phases, in which a mobile device probes the adjacent access points. This scanning phase is performed alternatively with communication. Sufficient Layer 3 information is conveyed in Layer 2 frames, which allows a mobile device to identify both its next Layer 2 and Layer 3 point of attachment. Simulation results show that this method performs well and enhance both the Layer 2 and the Layer 3 handover. The impact of handovers on real‐time application is also considerably minimized. Copyright © 2006 John Wiley & Sons, Ltd.

This document describes a mechanism that enhances mobile IP protocols to smoothly manage handovers for MNs equipped with multiple interfaces and moving across different links. For this purpose, the document provides precise indications on how to use the link layer events information to accelerate IP movement detection and optimize vertical inter-technology handovers. Experimentation results on vertical handovers between WLAN and GPRS networks are also given.

Given the relatively limited coverage area of 802.11 access points, stations moving inside WLAN are often required to perform a handover. The time needed for a STA to switch from one AP to another is too long for real-time applications to continue operating seamlessly, even if no layer 3 handover is to occur ulteriorly. Many solutions have been proposed for improving the layer 2 handover latency, but we have observed a lack of performance analysis and comparison of the different algorithms. In this article we present two new schemes that aim to enhance L2 handover mechanisms. The main characteristic of these new methods is to reduce the discovery time. We then provide an evaluation of four algorithms in order to analyse and compare solutions in six different scenarios

In ad hoc networks (MANETs), wireless nodes spontaneously collaborate to route packets among a multi-hop and versatile topology. While such networks have originaly been considered as autarkical systems, it becomes clear that there is a growing interest in connecting them to the Internet. In such a hybrid ad hoc network, one or more nodes act as gateways to the outside world. This situation requires the use of a global addressing scheme in order to allow end-to-end communications between MANET nodes and correspondents in the Internet. In this paper, we present and evaluate an IPv6 address autoconfiguration protocol based on the original concept of prefix continuity. This feature ensures that there exists, between a node N and its gateway G, a path of nodes such that all nodes on this path use the same IPv6 prefix than N and G. As a result, all the nodes of a given sub-network form a logical tree rooted at the sub- network's gateway, and in which all nodes share an identical IPv6 prefix. In a multiple-gateways and multiple-prefixes environment, our protocol proactively and dynamically reacts to topological changes in order to maintain the prefix continuity of each sub- network.

In this paper, we show a performance evaluation of the frame aggregation mechanism. This mechanism is introduced as a replacement for the power save polling (PSP) mode integrated in the IEEE 802.11 standard (1999). Since it uses bigger frame to achieve lower traffic and overhead, we investigate the consequences of packet loss on power consumption. Using this study, we are able to propose an adaptive mechanism to trigger frame aggregation based on the medium conditions as they can be observed from the station (STA) standpoint in an infrastructure environment.

The recent success of IEEE 802.11 networks and the increasing demand for real time services suggest a new usage of wireless devices. In particular, mobility management between access points and IPv6 networks must be fast enough to avoid loss of packets. In this paper, we propose a new mechanism to anticipate handovers. The movement anticipation consists of new potential access points discovery before the handover has even started. It also allows a station to set up in advance a new IPv6 configuration for the next location. We show by simulation that the anticipation mechanism strongly enhances both link and network layers handovers and significantly reduces the loss of packets.

In the near future, mobile devices can be integrated in several wireless and wired interfaces that can be connected to the Internet everywhere and all the time. This article discusses how to perform vertical handovers (flow redirection between interfaces) and proposes MMI (mobile IPv6 for multiple interfaces) which describes the use of mobile IPv6 to support multiple interfaces. We also provide an evaluation of MMI in a typical mobile environment.

This paper demonstrates a new way of saving energy in mobile devices using IEEE 802.11 network interfaces to communicate, which is achieved by adding consecutive frames into a single one and gathering their headers. An experimentation of this process has been carried out in order to validate its efficiency. The proposed mechanism focuses on IEEE 802.11 infrastructure networks.

The recent and increasing popularity of wireless transmission systems has initiated a strong interest in research on mobile communications. While most of this research effort focuses on unicast communications, there has also been a number of proposals to support multicasting with mobile members. However, the majority of these proposals, despite being innovative and elegant, remain at a research level, i.e. it is not clear if they could realistically be deployed in real large networks. In contrast, the IETF mobile IP working group has outlined two realistic methods that allow mobile nodes to join multicast groups. These proposals have however never been evaluated and compared. This paper therefore presents the results of a large number of simulations in which we have compared the efficiency of the two IETF solutions. We also propose the use of a new extension of the multicast listener delivery (MLD) protocol, which allows to rapidly resume the delivery of multicast data to a mobile receiver that has just performed a handover. The efficiency of this proposal is also compared with the already mentioned solutions of the IETF.

Mobile IPv6 (MIPv6), the IPv6 version of Mobile IP which is currently being developed by the Internet Engineering Task Force (IETF), is a protocol that describes how a mobile node can change its point of attachment to the Internet. While MIPv6 focuses on unicast communications, it also proposes two basic methods, known as bi-directional tunneling and remote subscription, to handle multicast communications with mobile nodes. In the mean time, the deployment of Source-Specific Multicast (SSM) is of great consideration, mainly for scalability reasons as it is a strong candidate that could be used to support inter-domain multicast routing. In the particular case of mobile IPv6 SSM sources, the mechanisms proposed in MIPv6 to support multicast communications introduce a number of problems that strongly degrade the SSM routing mode of operation. The intend of this document is to describe protocol enhancements that can be used to solve the problems introduced by mobile SSM sources when used with the current version of MIPv6. The extensions, mechanisms and mode of operation of the protocol proposed in this paper are denoted as MSSMSv6 (Mobile SSM Sources for IPv6).