Recent advances in wireless sensor networks have led to many new protocols specifically designed for sensor networks where energy awareness is an essential consideration. Most of the attention, however, has been given to the routing protocols since they might differ depending on the application and network architecture. This paper surveys recent routing protocols for sensor networks and presents a classification for the various approaches pursued. The three main categories explored in this paper are data-centric, hierarchical and location-based. Each routing protocol is described and discussed under the appropriate category. Moreover, protocols using contemporary methodologies such as network flow and QoS modeling are also discussed. The paper concludes with open research issues. 1.

Many new routing and MAC layer protocols have been proposed for wireless sensor networks tackling the issues raised by the resource constrained unattended sensor nodes in large-scale deployments. The majority of these protocols considered energy efficiency as the main objective and assumed data traffic with unconstrained delivery requirements. However, the growing interest in applications that demand certain end-toend performance guarantees and the introduction of imaging and video sensors have posed additional challenges. Transmission of data in such cases requires both energy and QoS aware network management in order to ensure efficient usage of the sensor resources and effective access to the gathered measurements. In this paper, we highlight the architectural and operational challenges of handling of QoS traffic in sensor networks. We report on progress make to-date and outline open research problems.

A generalized framework for loop-free routing based entirely on destination sequence numbers is presented. The framework eliminates the counting-to-infinity problem found in AODV and other on-demand routing protocols based on destination sequence numbers. The SequenceNumber Window Routing (SWR) protocol is presented as an example of this framework. SWR is compared via simulations with DSR, AODV and OLSR using networks of 50 and 100 mobile nodes; the results indicate that SWR is as efficient as AODV, without incurring counting to infinity.

Wireless ad hoc networks are inherently vulnerable, as any node can disrupt the communication of potentially any other node in the network. Many solutions to this problem have been proposed. In this paper, we take a fresh and comprehensive approach that addresses simultaneously three aspects: security, scalability and adaptability to changing network conditions. Our communication protocol, Castor, occupies a unique point in the design space: it does not use any control messages except simple packet acknowledgments, and each node makes routing decisions locally and independently without exchanging any routing state with other nodes. Its novel design makes Castor resilient to a wide range of attacks and allows the protocol to scale to large network sizes and to remain efficient under high mobility. We compare Castor against four representative protocols from the literature. Our protocol achieves up to two times higher packet delivery rates, particularly in large and highly volatile networks, while incurring no or only limited additional overhead. At the same time, Castor is able to survive more severe attacks and recovers from them faster.

Wireless ad hoc networks are inherently vulnerable, as any node can disrupt the communication of potentially any other node in the network. Many solutions to this problem have been proposed. In this paper, we take a fresh and comprehensive approach, simultaneously addressing three aspects: security, scalability and adaptability to changing network conditions. Our communication protocol, Castor, occupies a unique point in the design space: it does not use any control messages except simple packet acknowledgments, and each node makes routing decisions locally and independently of other nodes without exchanging routing state with them. This novel design makes Castor resilient to a wide range of attacks and allows it to scale to large network sizes and to remain efficient under high mobility. We compare Castor against four representative protocols from the literature. Our protocol achieves up to two times higher packet delivery rates, particularly in large and highly volatile networks, incurs no or only limited additional overhead and it is able to survive more severe attacks and recovers from them faster.

Abstract — This paper presents an experimental evaluation of a multi-service Ad-hoc network architecture, interconnected with a fixed network. This network supports the efficient delivery of services, unicast and multicast, legacy and multimedia, to users connected in the ad-hoc network. It contains the support for routing with delivery of multicast services, mobility, QoS mechanisms to support service differentiation and resource control responsive to node mobility as well as security, charging and rewarding mechanisms to ensure the correct behaviour of the users in the ad-hoc network. This paper experimentally evaluates the performance of the proposed mechanisms, and the influence and performance penalty introduced in the network, with the incremental inclusion of new functionalities. Results, although biased by the software implementations, may question the usage of ad-hoc networks for more than a minimal number of hops. Index Terms — ad-hoc networks, experimental characterization, multi-service, QoS. I.

being composed for a large number of node that are distributed geographically in a monitoring area. Considering this distribution and the restrictions of processing, memory and energy of this equipment, it becomes primordial that used mechanisms to increase its lifetime through the better use of the network resources. One of the ways to allow this improvement is the evaluation of the nodes resources in the routing protocols, avoiding routes composed by nodes with little energy in selection process. To deal this requirement this work will present a protocol created based in the AODV algorithm to improve the energy consumption of the nodes, mainly of whom already present a capacity. The simulations show that the proposed algorithm reached better results than other evaluated routing algorithms.

We present the Dynamic Incremental Routing (DIR) protocol, which features instantaneous loop-free routing of data packets based on their destination addresses (hop-byhop routing). Loop-free routes are maintained by using "feasible distances" to order the nodes with respect to a destination. Simulation results show that the performance of DIR is much better than the performance of AODV, DSR and OLSR, which are indicative of the state of the art in routing protocols.

In any on-demand routing protocol, sources flood route requests (RREQ) to build routes to destinations, and each new RREQ is identified uniquely with a source-sequenced label (SSL) consisting of the source identifier and a locally generated sequence number. As a RREQ propagates, it creates a directed acyclic graph (DAG), because nodes relay each RREQ only once. We present the first framework for loop-free on-demand routing in ad hoc networks that is based directly on SSLs, rather than on independent mechanisms, which has been the way in which prior on-demand routing protocols have been designed. Extensive simulation results for simple protocol instantiations of our new framework operating in scenarios with 50 and 100-nodes under different traffic patterns show that our new protocols outperform AODV (Ad hoc On Demand Distance Vector), DSR (Dynamic Source Routing), and OLSR (Optimized Link State Routing).

We present path verification routing (PVR) to enable robust, instantaneous on-demand loop-free routing of data packets based on their destination address in mobile ad hoc networks. PVR attains instantaneous loop-freedom by using a path verification technique without the necessity for sequence numbers, source-routed data packets, or nodal synchronization. The motivation for PVR is twofold. On the one hand, DSR provides loop-free routing but requires source routed data packets. On the other hand, AODV, which is based on destinationbased sequence numbers, is vulnerable to the counting-to-infinity problem and has route requests that in many cases must be answered by the destinations. Simulation experiments are used to show that the performance of PVR is comparable to or better than that of AODV, AODVbis, DSR and OLSR.