2,714 research outputs found

    Optimized Link State Routing Protocol (OLSR)

    Get PDF
    Network Working GroupNetwork Working GroupThis document describes the Optimized Link State Routing (OLSR) protocol for mobile ad hoc networks. The protocol is an optimization of the classical link state algorithm tailored to the requirements of a mobile wireless LAN. The key concept used in the protocol is that of multipoint relays (MPRs). MPRs are selected nodes which forward broadcast messages during the flooding process. This technique substantially reduces the message overhead as compared to a classical flooding mechanism, where every node retransmits each message when it receives the first copy of the message. In OLSR, link state information is generated only by nodes elected as MPRs. Thus, a second optimization is achieved by minimizing the number of control messages flooded in the network. As a third optimization, an MPR node may chose to report only links between itself and its MPR selectors. Hence, as contrary to the classic link state algorithm, partial link state information is distributed in the network. This information is then used for route calculation. OLSR provides optimal routes (in terms of number of hops). The protocol is particularly suitable for large and dense networks as the technique of MPRs works well in this context

    Speed-Aware Routing for UAV Ad-Hoc Networks

    Get PDF
    In this paper we examine mobile ad-hoc networks (MANET) composed by unmanned aerial vehicles (UAVs). Due to the high-mobility of the nodes, these networks are very dynamic and the existing routing protocols partly fail to provide a reliable communication. We present Predictive-OLSR an extension to the Optimized Link-State Routing (OLSR) protocol: it enables efficient routing in very dynamic conditions. The key idea is to exploit GPS information to aid the routing protocol. Predictive-OLSR weights the expected transmission count (ETX) metric, taking into account the relative speed between the nodes. We provide numerical results obtained by a MAC-layer emulator that integrates a flight simulator to reproduce realistic flight conditions. These numerical results show that Predictive-OLSR significantly outperforms OLSR and BABEL, providing a reliable communication even in very dynamic conditions.Comment: submitted to GlobeCom'13 Workshop - Wi-UA

    Analisis Kinerja Protocol OLSR Pada Jaringan Ad Hoc

    Get PDF
    Abstrak: Analisis kinerja dengan menggunakan protocol Optimized Link State Routing (OLSR) pada jaringan ad hoc telah didapatkan hasil Quality of Service atau QoS terhadap nilai throughput, packet loss dan delay serta uji performa proses transfer data dilakukan dengan menggunakan software Network Simulator 3 (NS-3) pada sistem operasi Linux Ubuntu, berdasarkan jumlah node yang terus ditambah sesuai dengan skenario pengujian pada jaringan ad hoc. Skenario pengujian dilakukan dengan penambahan node secara bertahap mulai dari 10 node, kemudian ditambahkan menjadi 20 node, sampai berjumlah 40 node. Hasil analisis kinerja protocol Optimized Link State Routing (OLSR) serta pengukuran yang didapatkan terhadap nilai throughput, menghasilkan nilai rata-rata sebesar 3.1872 Kbps sehingga termasuk ke dalam kategori bagus. Nilai packet loss menghasilkan rata-rata sebesar 3,48% termasuk kedalam kategori bagus dan nilai delay menghasilkan rata-rata 6.824 ms yang juga masuk ke dalam kategori bagus. Hasil akhir analisis kinerja dengan menggunakan protocol Optimized Link State Routing (OLSR) pada jaringan ad hoc telah disajikan dalam bentuk grafik untuk memudahkan proses pengamatan dan penelitian selanjutnya

    OSPF-style Database Exchange and Reliable Synchronization in the OLSR

    Get PDF
    The Optimized Link-State Routing protocol (OLSR) is a proactive link-state routing protocol. While similar to the well-known Internet routing protocol OSPF, OLSR is designed to be simple, and to maintain connectivity in face of highly dense and dynamic networks, while being ressource-economic (battery, bandwidth etc.) These characteristics make OLSR suitable as an underlaying routing protocol in a wide range of ad-hoc sensor networks. In this paper, we introduce an extension to OLSR: OSPF-style database exchange and reliable synchronization. The goal of this extension is to provide a mechanism, through which nodes in an ad-hoc sensor network can detect and correct discrepancies in their link-state databases. We qualify why the mechanism, found in OSPF, is not directly applicable for ad-hoc sensor networks, describe an adopted mechanism, accomplishing the same goal, and evaluate the performance of this mechanism in comparison to the database exchange mechanism found in OSPF. We finally discuss some applications of database exchange and reliable synchronization in ad-hoc sensor networks

    Routing in Mobile Ad-Hoc Networks using Social Tie Strengths and Mobility Plans

    Full text link
    We consider the problem of routing in a mobile ad-hoc network (MANET) for which the planned mobilities of the nodes are partially known a priori and the nodes travel in groups. This situation arises commonly in military and emergency response scenarios. Optimal routes are computed using the most reliable path principle in which the negative logarithm of a node pair's adjacency probability is used as a link weight metric. This probability is estimated using the mobility plan as well as dynamic information captured by table exchanges, including a measure of the social tie strength between nodes. The latter information is useful when nodes deviate from their plans or when the plans are inaccurate. We compare the proposed routing algorithm with the commonly-used optimized link state routing (OLSR) protocol in ns-3 simulations. As the OLSR protocol does not exploit the mobility plans, it relies on link state determination which suffers with increasing mobility. Our simulations show considerably better throughput performance with the proposed approach as compared with OLSR at the expense of increased overhead. However, in the high-throughput regime, the proposed approach outperforms OLSR in terms of both throughput and overhead

    Identifying Design Requirements for Wireless Routing Link Metrics

    Full text link
    In this paper, we identify and analyze the requirements to design a new routing link metric for wireless multihop networks. Considering these requirements, when a link metric is proposed, then both the design and implementation of the link metric with a routing protocol become easy. Secondly, the underlying network issues can easily be tackled. Thirdly, an appreciable performance of the network is guaranteed. Along with the existing implementation of three link metrics Expected Transmission Count (ETX), Minimum Delay (MD), and Minimum Loss (ML), we implement inverse ETX; invETX with Optimized Link State Routing (OLSR) using NS-2.34. The simulation results show that how the computational burden of a metric degrades the performance of the respective protocol and how a metric has to trade-off between different performance parameters

    Multipath OLSR: Simulation and Testbed

    Get PDF
    MP-OLSR is a multipath routing protocol based on OLSR (Optimized Link State Routing). The multipath routing protocol is expected to provide more stable routes for the network. In this paper, several topics about MP-OLSR are discussed. We begin with introducing the functionalities of MP-OLSR, which includes topology sensing, routing computation, route recovery and loop detection. Then a testbed is implemented to verify the availability of MP-OLSR. Given OLSR one of the most populated proactive protocols for ad hoc networks, the compatibility between MP-OLSR and OLSR is also discussed. The results based on simulator and our testbed show that MP-OLSR could offer more stable data transmission over the unstable wireless interface. And it could cooperate well with the established OLSR protocol

    A Study on Preventing Node Isolation Attack in OLSR Protocol

    Get PDF
    AbstractA mobile ad hoc network (MANET) is a wireless communication system of continuously self-configuring and infrastructure-less network of mobile devices which can move independently in any direction at any time.Routing protocols is required for message exchange in MANET. The most widely used routing protocol is OLSR (Optimized Link State Routing Protocol). It is efficient in bandwidth utilization and path calculation. But it is vulnerable to many types of attacks. In this paper, we discuss about various methods used to prevent a type of Denial of Service (DoS) attack called the node isolation attack that is capable to compromise OLSR protocol
    • …
    corecore