Cache timeout strategies for on-demand routing in MANETs

Varying the route caching scheme can significantly change network performance for on-demand routing protocols in mobile ad hoc networks (MANETs). Initial route caching schemes retain paths or links until they are shown to be broken. However, stale routing information can degrade network performance with latency and extra routing overhead. Therefore, more recent caching schemes delete links at some fixed time after they enter the cache. This paper proposes using either the expected path duration or the link residual time as the link cache timeout. These mobility metrics are theoretically calculated for an appropriate random mobility model. Simulation results in NS2 show that both of the proposed link caching schemes can improve network performance in the dynamic source routing protocol (DSR) by reducing dropped data packets, latency and routing overhead, with the link residual time scheme out-performing the path duration scheme.IEEE, South Australian Sectio

Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks

This doctoral thesis deals with naming and address resolution in heterogeneous networks to be used in disaster scenarios. Such events could damage the communication infrastructure in parts or completely. To reestablish communication, Mobile Ad hoc Networks (MANETs) could be used where central entities have to be eliminated broadly. The main focus of the thesis lies on two things: an addressing scheme that helps to find nodes, even if they frequently change the subnet and the local addressing, by introducing an identifying name layer; and a MANET-adapted substitution of the Domain Name System (DNS) in order to resolve node identities to changing local addresses. We present our solution to provide decentralized name resolution based on different underlying routing protocols embedded into an adaptive routing framework. Furthermore, we show how this system works in cascaded networks and how to extend the basic approach to realize location-aware service discovery.Auch im Buchhandel erhältlich: Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks / Sebastian Schellenberg Ilmenau : Univ.-Verl. Ilmenau, 2016. - xvi, 177 Seiten ISBN 978-3-86360-129-4 Preis (Druckausgabe): 17,60

An Analysis Framework for Mobility Metrics in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) have inherently dynamic topologies. Under these difficult circumstances, it is essential to have some dependable way of determining the reliability of communication paths. Mobility metrics are well suited to this purpose. Several mobility metrics have been proposed in the literature, including link persistence, link duration, link availability, link residual time, and their path equivalents. However, no method has been provided for their exact calculation. Instead, only statistical approximations have been given. In this paper, exact expressions are derived for each of the aforementioned metrics, applicable to both links and paths. We further show relationships between the different metrics, where they exist. Such exact expressions constitute precise mathematical relationships between network connectivity and node mobility. These expressions can, therefore, be employed in a number of ways to improve performance of MANETs such as in the development of efficient algorithms for routing, in route caching, proactive routing, and clustering schemes

Review on the Simulation of Cooperative Caching Schemes for MANETs

In this paper, a review of the main simulation parameters utilized to evaluate the performance of cooperative caching schemes in Mobile Ad Hoc Networks is presented. Firstly, a taxonomy of twenty five caching schemes proposed in the literature about Mobile Ad Hoc Networks is defined. Those caching schemes are briefly described in order to illustrate their basis and fundamentals. The review takes into consideration the utilized network simulator, the wireless connection standard, the propagation model and routing protocol, the employed simulation area and number of data servers, the number of mobile devices and their coverage area, the mobility model, the number of documents in the network, the replacement policy and cache size, the mean time between requests, the document popularity distribution, the TTL (Time To Live) of the documents and the simulation time. Those simulation parameters have been compared among the evaluation of the studied cooperative caching schemes in order to obtain the most common utilized values. This work will allow to compare the performance of the proposed cooperative caching schemes using a common simulation environment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Survey on QoE/QoS Correlation Models for Video Streaming over Vehicular Ad-hoc Networks

Vehicular Ad-hoc Networks (VANETs) are a new emerging technology which has attracted enormous interest over the last few years. It enables vehicles to communicate with each other and with roadside infrastructures for many applications. One of the promising applications is multimedia services for traffic safety or infotainment. The video service requires a good quality to satisfy the end-user known as the Quality of Experience (QoE). Several models have been suggested in the literature to measure or predict this metric. In this paper, we present an overview of interesting researches, which propose QoE models for video streaming over VANETs. The limits and deficiencies of these models are identified, which shed light on the challenges and real problems to overcome in the future

Exploiting the power of multiplicity: a holistic survey of network-layer multipath

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work

Mobility Metrics for Routing in MANETs

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without the need for base stations or any other pre–existing network infrastructure. In a peer-to-peer fashion, mobile nodes can communicate with each other by using wireless multihop communication. Due to its low cost, high flexibility, fast network establishment and self-reconfiguration, ad hoc networking has received much interest during the last ten years. However, without a fixed infrastructure, frequent path changes cause significant numbers of routing packets to discover new paths, leading to increased network congestion and transmission latency over fixed networks. Many on-demand routing protocols have been developed by using various routing mobility metrics to choose the most reliable routes, while dealing with the primary obstacle caused by node mobility. ¶ In the first part, we have developed an analysis framework for mobility metrics in random mobility model. ... ¶ In the second part, we investigate the mobility metric applications on caching strategies and hierarchy routing algorithm. ..

Enhancing Performance by Salvaging Route Reply Messages in On-Demand Routing Protocols for MANETs

Researchers prefer on-demand routing protocols in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination responds by sending a route reply (RREP) message to the source. The RREP travels hop by hop on the discovered route in the reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to node mobility or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet - discard the packet and initiate a route error message. This is highly undesirable because a RREP message has a lot at stake – it is obtained at the cost of a large number of RREQ transmissions, which is an expensive and timeconsuming process. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. We present two schemes to salvage an undeliverable RREP. Scheme one actively sends a one-hop salvage request message to find an alternative path to the source, while scheme two passively maintains a backup path to the source. Furthermore, we present the design of two SRR schemes in AODV and prove that routes are loop-free after a salvaging. We conduct extensive simulations to evaluate the performance of SRR, and the simulation results confirm the effectiveness of the SRR approach