2,714 research outputs found
Optimized Link State Routing Protocol (OLSR)
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
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
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
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
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
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
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
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
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