A COMMUNICATION FRAMEWORK FOR MULTIHOP WIRELESS ACCESS AND SENSOR NETWORKS: ANYCAST ROUTING & SIMULATION TOOLS

The reliance on wireless networks has grown tremendously within a number of varied application domains, prompting an evolution towards the use of heterogeneous multihop network architectures. We propose and analyze two communication frameworks for such networks. A first framework is designed for communications within multihop wireless access networks. The framework supports dynamic algorithms for locating access points using anycast routing with multiple metrics and balancing network load. The evaluation shows significant performance improvement over traditional solutions. A second framework is designed for communication within sensor networks and includes lightweight versions of our algorithms to fit the limitations of sensor networks. Analysis shows that this stripped down version can work almost equally well if tailored to the needs of a sensor network. We have also developed an extensive simulation environment using NS-2 to test realistic situations for the evaluations of our work. Our tools support analysis of realistic scenarios including the spreading of a forest fire within an area, and can easily be ported to other simulation software. Lastly, we us our algorithms and simulation environment to investigate sink movements optimization within sensor networks. Based on these results, we propose strategies, to be addressed in follow-on work, for building topology maps and finding optimal data collection points. Altogether, the communication framework and realistic simulation tools provide a complete communication and evaluation solution for access and sensor networks

Priority Based Routing for Mobile Peer-To-Peer Communications

In a Mobile Peer-to-Peer (MP2P) network, mobile nodes share their resources among one another in a mobile wireless environment. Communication among nodes in MP2P network has become an important area for research due to the significance of its applications. The success of these MP2P applications depends on the number of users in the network, popularity of services offered, quick response and faster access to services. Some services offered could be more popular than others and some peers may contribute more to the network by catering to more requests compared to other peers. In priority based routing mechanism, there is an increase in the priority of a peer with the increase in the number of times it provides services to other peers. The priority of a shared service also increases as the number of requests for that service increases. Also, the mechanism of priority based mobile peer-to-peer routing provides higher priority for traffic destined to high contributing peers and the traffic of popular services, during routing. This would provide high contributing peers quicker response and faster access to services. Hence, this mechanism motivates more users to join the MP2P network and contribute more to the network

Lanes. A lightweigth overlay for service discovery in mobile ad hoc networks

The ability to discover services offered in a mobile ad hoc network is the major prerequisite for effective usability of these networks. Unfortunately, existing approaches to service trading are not well suited for these highly dynamic topologies since they either rely on centralized servers or on resource-consuming query flooding. Application layer overlays seem to be a more promising approach. However, existing solutions like the Content-Addressable Network (CAN) are especially designed for internet based peer-to-peer networks yielding structural conditions that are far too complex for ad hoc networks. Therefore, in this paper, we propose a more lightweight overlay structure: lanes. We present algorithms to correct and optimize its structure in case of topology changes and show how it enables the trading of services specified by arbitrary descriptions

An Enhanced Ipv6 Anycast Routing Protocol Using Protocol Independent Multicast-Sparse Mode With Mobile Ipv6

Anycast routing is an efficient routing mechanism that enables the network to choose the nearest and most appropriate server very quickly. However, IPv6 Anycast is not used widely in practice yet, and there are many reasons for this. Firstly, IPv6 Anycast does not have its own standard protocol because anycast builds its anycast membership tree like multicast does but unlike multicast it sends only to one of the groups using unicast mechanism. The other problem is that IPv6 Anycast mechanism could not provide stateful connections between the sender and the receiver because the sender always change the receiver based on the metric or the distance. In this thesis a new IPv6 anycast routing protocol is developed to provide a stateful communication between the anycast sender and the receiver. Protocol Independent Multicast-Sparse Mode (PIM-SM) has been chosen to establish the new IPv6 anycast mechanism because of many similar properties between multicast and anycast. A new variable is proposed in the routing table called Best Metric Factor (BMF) to describe the status of the receiver (free or Busy). This factor is used to decide the appropriate receiver to choose, the advantage of the proposed design can be observed easily when there are multi-anycast senders sending their traffic to the appropriate receiver at the same time. Next we improve the mechanism by building a direct connection between the anycast sender and the anycast receiver using route optimization by mapping the objects in Mobile IPv6 to the objects in the proposed mechanism. This is because there are many similar properties between Mobile IPv6 and the proposed design. The proposed mechanism has been shown to achieve a good performance with multi-anycast senders and can provide a stateful communication between the sender and the appropriate receiver

Enabling the web of things: facilitating deployment, discovery and resource access to IoT objects using embedded web services

Today, the IETF Constrained Application Protocol (CoAP) is being standardised. CoAP takes the internet of things to the next level: it enables the implementation of RESTful web services on embedded devices, thus enabling the construction of an easily accessible web of things. However, before tiny objects can make themselves available through embedded web services, several manual configuration steps are still needed to integrate a sensor network within an existing networking environment. In this paper, we describe a novel self-organisation solution to facilitate the deployment of constrained networks and enable the discovery, end-to-end connectivity and service usage of these newly deployed sensor nodes. By using embedded web service technology, the need of other protocols on these resource constrained devices is avoided. It allows automatic hierarchical discovery of CoAP servers, resulting in a browsable hierarchy of CoAP servers, which can be accessed both over CoAP and hypertext transfer protocol.The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 258885 (SPITFIRE project), from the iMinds ICON project O’CareCloudS, from a VLIR PhD grant to Isam Ishaq and through an FWO pos tdoc research grant for Eli De Poorter

Anycast services and its applications

Anycast in next generation Internet Protocol is a hot topic in the research of computer networks. It has promising potentials and also many challenges, such as architecture, routing, Quality-of-Service, anycast in ad hoc networks, application-layer anycast, etc. In this thesis, we tackle some important topics among them. The thesis at first presents an introduction about anycast, followed by the related work. Then, as our major contributions, a number of challenging issues are addressed in the following chapters. We tackled the anycast routing problem by proposing a requirement based probing algorithm at application layer for anycast routing. Compared with the existing periodical based probing routing algorithm, the proposed routing algorithm improves the performance in terms of delay. We addressed the reliable service problem by the design of a twin server model for the anycast servers, providing a transparent and reliable service for all anycast queries. We addressed the load balance problem of anycast servers by proposing new job deviation strategies, to provide a similar Quality-of-Service to all clients of anycast servers. We applied the mesh routing methodology in the anycast routing in ad hoc networking environment, which provides a reliable routing service and uses much less network resources. We combined the anycast protocol and the multicast protocol to provide a bidirectional service, and applied the service to Web-based database applications, achieving a better query efficiency and data synchronization. Finally, we proposed a new Internet based service, minicast, as the combination of the anycast and multicast protocols. Such a service has potential applications in information retrieval, parallel computing, cache queries, etc. We show that the minicast service consumes less network resources while providing the same services. The last chapter of the thesis presents the conclusions and discusses the future work

Enabling the web of things: facilitating deployment, discovery and resource access to IoT objects using embedded web services

Today, the IETF Constrained Application Protocol (CoAP) is being standardised. CoAP takes the internet of things to the next level: it enables the implementation of RESTful web services on embedded devices, thus enabling the construction of an easily accessible web of things. However, before tiny objects can make themselves available through embedded web services, several manual configuration steps are still needed to integrate a sensor network within an existing networking environment. In this paper, we describe a novel self-organisation solution to facilitate the deployment of constrained networks and enable the discovery, end-to-end connectivity and service usage of these newly deployed sensor nodes. By using embedded web service technology, the need of other protocols on these resource constrained devices is avoided. It allows automatic hierarchical discovery of CoAP servers, resulting in a browsable hierarchy of CoAP servers, which can be accessed both over CoAP and hypertext transfer protocol

Effective Mobile Routing Through Dynamic Addressing

Military communications has always been an important factor in military victory and will surely play an important part in future combat. In modern warfare, military units are usually deployed without existing network infrastructure. The IP routing protocol, designed for hierarchical networks cannot easily be applied in military networks due to the dynamic topology expected in military environments. Mobile ad-hoc networks (MANETs) represent an appropriate network for small military networks. But, most ad-hoc routing protocols suffer from the problem of scalability for large networks. Hierarchical routing schemes based on the IP address structure are more scalable than ad-hoc routing but are not flexible for a network with very dynamic topology. This research seeks a compromise between the two; a hybrid routing structure which combines mobile ad-hoc network routing with hierarchical network routing using pre-planned knowledge about where the various military units will be located and probable connections available. This research evaluates the performance of the hybrid routing and compares that routing with a flat ad-hoc routing protocol, namely the Ad-hoc On-demand Distance Vector (AODV) routing protocol with respect to goodput ratio, packet end to- end delay, and routing packet overhead. It shows that hybrid routing generates lower routing control overhead, better goodput ratio, and lower end-to-end packet delay than AODV routing protocol in situations where some a-priori knowledge is available

An anycast based feedback aggregation scheme for efficient network transparency in cross-layer design

To ensure Quality of Service for multimedia data sessions in next generation mobile telecommunication systems, jointly-optimized cross-layer architectures were introduced recently. Such shemes usually require an adaptive media source which is able to modify the main parameters of ongoing connections by transferring control and feedback information via the network and through different protocol layers from application layer to physical layer and vice versa, according to the actual state of the path between peer nodes. This concept of transmitting cross-layer information is referred as network transparency in the literature, meaning that the underlying infrastructure is almost invisible to all the entities involved in joint optimization due to the continuous conveyance of cross-layer feedbacks. In this paper we introduce and evaluate a possible solution for reducing the network overhead caused by this volume of information exchange. Our soulution is based on the anycasting communication paradigm and creates a hierarchical data aggregation scheme allowing to adapt each entity of the multimedia transmission chain based on frequent feedbacks and even so in a low-bandwitdh manner