Ad hoc On-Demand Distance Vector (AODV) Routing
01 Jul 2003-Vol. 3561, pp 1-37
TL;DR: A logging instrument contains a pulsed neutron source and a pair of radiation detectors spaced along the length of the instrument to provide an indication of formation porosity which is substantially independent of the formation salinity.
Abstract: The Ad hoc On-Demand Distance Vector (AODV) routing protocol is intended for use by mobile nodes in an ad hoc network. It offers quick adaptation to dynamic link conditions, low processing and memory overhead, low network utilization, and determines unicast routes to destinations within the ad hoc network. It uses destination sequence numbers to ensure loop freedom at all times (even in the face of anomalous delivery of routing control messages), avoiding problems (such as "counting to infinity") associated with classical distance vector protocols.
Citations
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TL;DR: This article presents an overview of this emerging technology, focusing on the technical merits and related standards activities of IEEE and ZigBee that are actively applying the concept of multi-hop mesh techniques in the field of wireless networking technologies, ranging from personal area networks (PANs) to metropolitan areas networks (MANs).
Abstract: Wireless mesh networking is a promising technology for numerous applications which appeals especially to those applications that cannot be directly supported by other wireless technologies. The commercial success of Wi-Fi and the advances in many wireless technologies have in part stimulated the development of wireless mesh networks. The persistent driving force, however, comes from the envisioned advantages of wireless mesh techniques themselves, including extended coverage, robustness, self-configuration, easy maintenance, and low cost. This article presents an overview of this emerging technology, focusing on the technical merits and related standards activities of IEEE and ZigBee that are actively applying the concept of multi-hop mesh techniques in the field of wireless networking technologies, ranging from personal area networks (PANs) to metropolitan area networks (MANs)
232 citations
01 Feb 2003
TL;DR: Experiments demonstrate that adding proactive route selection and maintenance to DSR and AODV (on-demand ad hoc routing protocols) significantly reduces the number of broken paths, with a small increase in protocol overhead.
Abstract: Routing in ad hoc networks is a challenging problem because nodes are mobile and links are continuously being created and broken. Existing on-demand ad hoc routing algorithms initiate route discovery only after a path breaks, incurring a significant cost in detecting the disconnection and establishing a new route. In this work, we investigate adding proactive route selection and maintenance to on-demand ad hoc routing algorithms. More specifically, when a path is likely to be broken, a warning is sent to the source indicating the likelihood of a disconnection. The source can then initiate path discovery early, potentially avoiding the disconnection altogether. A path is considered likely to break when the received packet power becomes close to the minimum detectable power (other approaches are possible). Care must be taken to avoid initiating false route warnings due to fluctuations in received power caused by fading, multipath effects and similar random transient phenomena. Experiments demonstrate that adding proactive route selection and maintenance to DSR and AODV (on-demand ad hoc routing protocols) significantly reduces the number of broken paths, with a small increase in protocol overhead. Packet latency and jitter go down in most cases. Because preemptive routing reduces the number of broken paths, it also has a secondary effect on TCP performance--unnecessary congestion handling measures are avoided. This is observed for TCP traffic under different traffic patterns (telnet, ftp and http). Additionally, we outline some problems in TCP performance in ad hoc environments.
231 citations
01 Oct 2006
TL;DR: This paper explores how serious the broadcast storm problem is in both MANET and VANET by examining how broadcast packets propagate in a 2-dimensional open area and on a straight road or highway scenarios and proposes three novel distributed broadcast suppression techniques; i.e., weighted p-persistence, slotted 1- Persistence, and slotted p- persistence schemes.
Abstract: Routing protocols developed for ad hoc wireless networks use broadcast transmission to either discover a route or disseminate information. More specifically, reactive routing protocols has to flood the network with a route request (RREQ) message in order to find an optimal route to the destination. Several applications developed for vehicular ad hoc wireless networks (VANET), which is a subset of MANET, rely on broadcast to propagate useful traffic information to other vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem. In this paper, we explore how serious the broadcast storm problem is in both MANET and VANET by examining how broadcast packets propagate in a 2-dimensional open area and on a straight road or highway scenarios. In addition, we propose three novel distributed broadcast suppression techniques; i.e., weighted p-persistence, slotted 1-persistence, and slotted p- persistence schemes. Our simulation results show that the proposed schemes can achieve up to 90% reduction in packet loss rate while keeping the end-to-end delay at acceptable levels for most VANET applications. They can also be used together with the route discovery process to guide the routing protocols to select routes with fewer hop counts.
230 citations
Cites background from "Ad hoc On-Demand Distance Vector (A..."
...Some routing protocols, however, have various features designed to avoid flooding the network and creating broadcast storm [8, 9]....
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16 Jul 2001
TL;DR: Experiments demonstrate that adding proactive route selection and maintenance to DSR and AODV (on-demand ad hoc routing protocols) significantly reduces the number of broken paths, with a small increase in protocol overhead.
Abstract: Existing on-demand ad-hoc routing algorithms initiate route discovery only after a path breaks, incurring a significant cost in detecting the disconnection and establishing a new route. In this work, we investigate adding proactive route selection and maintenance to on-demand ad-hoc routing algorithms. More specifically, when a path is likely to be broken, a warning is sent to the source indicating the likelihood of a disconnection. The source can then initiate path discovery early, potentially avoiding the disconnection altogether. A path is considered likely to break when the received packet power becomes close to the minimum detectable power (other approaches are possible). Care must be taken to avoid initiating false route warnings due to fluctuations in received power caused by fading, multipath effects and similar random transient phenomena. Experiments demonstrate that adding proactive route selection and maintenance to DSR and AODV (on-demand ad hoc routing protocols) significantly reduces the number of broken paths, with a small increase in protocol overhead. Packet latency and jitter also goes down in most cases. We also show some experimental results obtained by running TCP on top of the proactive routing schemes proposed. Several improvements and extensions are also discussed. Pro-active route selection and maintenance is general and can be used with other routing algorithms and optimizations to them.
230 citations
Cites background or methods or result from "Ad hoc On-Demand Distance Vector (A..."
...Figure 9 shows number of AODV packets introduced....
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...Similarly, Ad hoc OnDemand Distance Vector Routing (AODV) [19] is an on-demand version of DSDV where the path discovery results in exchange of the portions of the routing tables necessary for establishing the route....
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...We note that this aspect of the implementation can be significantly optimized (reducing both the number of discoveries and the cost per discovery) by using effective caching with a higher success rate (for example, the scheme used in AODV [19]), and query localization [6, 13]....
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...As a case study, DSR and AODV were extended for proactivity (we call the modified algorithms PDSR and PAODV respectively)....
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...To illustrate that the results are not specific to DSR, we incorporated preemptive maintenance into AODV, a distance vector based routing algorithm for ad hoc networks....
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01 Jan 2006
TL;DR: AODV and OLSR performance in realistic urban scenarios is evaluated under varying metrics such as node mobility and vehicle density, and with varying traffic rates to provide a qualitative assessment of the applicability of the protocols in different vehicular scenarios.
Abstract: A Vehicular Ad Hoc Network (VANET) is an instance of MANETs that establishes wireless connections between cars. In VANETs, routing protocols and other techniques must be adapted to vehicular-specific capabilities and requirements. As many previous works have shown, routing performance is greatly dependent to the availability and stability of wireless links, which makes it a crucial parameter that should not be neglected in order to obtain accurate performance measurements in VANETs. Although routing protocols have already been analyzed and compared in the past, simulations and comparisons have almost always been done considering random motions. But could we assess that those results hold if performed using realistic urban vehicular motion patterns ? In this paper, we evaluate AODV and OLSR performance in realistic urban scenarios. We study those protocols under varying metrics such as node mobility and vehicle density, and with varying traffic rates. We show that clustering effects created by cars aggregating at intersections have remarkable impacts on evaluation and performance metrics. Our objective is to provide a qualitative assessment of the applicability of the protocols in different vehicular scenarios.
229 citations
Cites background from "Ad hoc On-Demand Distance Vector (A..."
...Such relays are called Multi-Point Relays (MPR)....
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...As the maximum number of hops is approximately 2 hops on average, and as MPR has been purposely created to optimize the number of hops in its two hops neighborhood, it is not surprising that AODV creates routes 15% longer than OLSR....
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...Based on this, the dedicated MPR algorithm minimizes the number of active relays needed to cover all 2-hops neighbors....
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...In order to construct and maintain its routing tables, OLSR periodically transmit link state information over the MPR backbone....
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...A node forwards a packet if and only if it has been elected as MPR by the sender node....
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12 Nov 2001
TL;DR: In this article, a logging instrument contains a pulsed neutron source and a pair of radiation detectors spaced along the length of the instrument to provide an indication of formation porosity which is substantially independent of the formation salinity.
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207 citations
"Ad hoc On-Demand Distance Vector (A..." refers methods in this paper
...This section defines other terminology used with AODV that is not already defined in [3]....
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