563 research outputs found

    Routing Optimizing Decisions in MANET: The Enhanced Hybrid Routing Protocol (EHRP) with Adaptive Routing based on Network Situation

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    Mobile ad hoc networks (MANETs) are wireless networks that operate without a fixed infrastructure or base station. In MANETs, each node acts as a data source and a router, establishing connections with its neighboring nodes to facilitate communication. This research has introduced the Enhanced Hybrid Routing Protocol (EHRP), which combines the OLSR, AOMDV, and AODV routing protocols while considering the network situation for improved performance. The EHRP protocol begins by broadcasting a RREP (Route Reply) packet to discover a route. The selection of routing options is based on the current network situation. To determine the distance between the source and destination nodes, the proposed EHRP initiates a RREQ (Route Request) packet. In situations where network mobility exceeds the capabilities of the AODV protocol, the EHRP protocol can utilize the OLSR routing protocol for route selection and data transmission, provided that at least 70% of the network nodes remain stable. Additionally, the EHRP protocol effectively handles network load and congestion control through the utilization of the AOMDV routing protocol. Compared to the hybrid routing protocol, the enhanced hybrid routing protocol (EHRP) demonstrates superior performance. Its incorporation of the OLSR, AOMDV, and AODV protocols, along with its adaptive routing adaptation based on network conditions, allows for efficient network management and improved overall network performance. The analysis of packet delivery ratio for EHRP and ZRP reveals that EHRP achieves a packet delivery ratio of 98.01%, while ZRP achieves a packet delivery ratio of 89.99%. These results indicate that the enhanced hybrid routing protocol (EHRP) outperforms the hybrid routing protocol (ZRP) in terms of packet delivery ratio. EHRP demonstrates a higher level of success in delivering packets to their intended destinations compared to ZRP. The analysis of normal routing load for EHRP and ZRP reveals that EHRP exhibits a normal routing load of 0.13%, while ZRP exhibits a higher normal routing load of 0.50%. Based on these results, it can be concluded that the performance of the Enhanced Hybrid Routing Protocol (EHRP) is significantly better than that of the Hybrid Routing Protocol (ZRP) when considering the normal routing load. EHRP demonstrates a lower level of routing overhead and more efficient resource utilization compared to ZRP in scenarios with normal routing load. When comparing the average end-to-end delay between the Enhanced Hybrid Routing Protocol (EHRP) and ZRP, the analysis reveals that EHRP achieves an average delay of 0.06, while ZRP exhibits a higher average delay of 0.23. These findings indicate that the Enhanced Hybrid Routing Protocol (EHRP) performs better than ZRP in terms of average end-to-end delay. EHRP exhibits lower delay, resulting in faster and more efficient transmission of data packets from source to destination compared to ZRP. After considering the overall parameter matrix, which includes factors such as normal routing load, data send and receive throughput, packet delivery ratio, and average end-to-end delay, it becomes evident that the performance of the Enhanced Hybrid Routing Protocol (EHRP) surpasses that of the current hybrid routing protocol (ZRP). Across these metrics, EHRP consistently outperforms ZRP, demonstrating superior performance and efficiency. The Enhanced Hybrid Routing Protocol (EHRP) exhibits better results in terms of normal routing load, higher throughput for data transmission and reception, improved packet delivery ratio, and lower average end-to-end delay. Overall, EHRP offers enhanced performance and effectiveness compared to the existing hybrid routing protocol (ZRP)

    Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks

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    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

    Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks

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    Service discovery plays an important role in mobile ad hoc networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead.This work is partially supported by the Spanish Ministry of Science and Innovation through the Continuity of Service, Security and QoS for Transportation Systems (CONSEQUENCE) (TEC2010-20572-C02-01/02) and INcident monitoRing In Smart COmmunities (INRISCO) (TEC2014-54335-C4-2-R) projects. We thank the editor and anonymous reviewers for their constructive comments, which helped us to improve our manuscript

    Comparative Analysis of Routing Protocols for Mobile Ad hoc Networks

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    Mobile ad-hoc networks (MANETs) are selfconfiguring networks of nodes connected via wireless. This kind of networks is currently one of the most important research subjects, due to the huge variety of applications (emergency, military, etc...). In MANETs, each node acts both as host and as router, thus, it must be capable of forwarding packets to other nodes. Topologies of these networks change frequenly. To solve this problem, special routing protocols for MANETs are needed because traditional routing protocols for wired networks cannot work efficiently in MANETs

    Integrating peer-to-peer functionalities and routing in mobile ad-hoc networks

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    Mobile Ad-hoc Networks (MANETs) impose strict requirements in terms of battery life, communication overhead and network latency, therefore optimization should be made to applications and services such as domain name service (DNS), dynamic host configuration protocol (DHCP) and session initiation protocol (SIP) if they are to be considered for use on MANETs. Due to the decentralized and self-organizing nature of MANETs, such applications could utilize a distributed name resolution/data storage service. Distributed Hash Tables (DHTs) enable these features by virtually organizing the network topology in a peer-to-peer (P2P) overlay. P2P overlays have been designed to operate on the application layer without knowledge of the underlying network thus causing poor performance. To address this problem, we propose and evaluate two different DHTs integrated with MANET routing in order to optimize the overall performance of MANET communications when P2P applications and services are used. Both architectures share the same functionality such as decentralization, self-reorganization, and self-healing but differ in MANET routing protocol. Performance evaluation using the NS2 simulator shows that these architectures are suited to different scenarios namely increasing network size and peer velocity. Comparisons with other well-known solutions have proven their efficiency with regard to the above requirements

    Modeling and Performance Evaluation of MANET Handover

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    A Mobile Ad Hoc Network (MANET) is an unstructured collection of wireless nodes that move arbitrarily and use multi-hop protocols to communicate between each other. There is not a predefined infrastructure in a MANET as there is in other types of wireless networks. Now days, MANET networks integrate with other networks, like the Internet, permitting ad hoc nodes to communicate with hosts placed in any part of the world. But the integration of MANETs with fixed infrastructures must be carefully studied to evaluate how it performs. In such integrated scenario, commonly known as Hybrid Ad Hoc Network, a MANET can be seen as an extension to the existing infrastructure, whose mobile nodes seamlessly communicate with hosts on the fixed network by forwarding packets throughout the gateways found on the edge that join both types of network. Connecting MANETs to the Internet does not come without difficulties. Ad hoc routing protocols work different than the regular routing protocols used on the Internet, and their interoperability becomes an important issue. But when MANETs integrate with the Internet, a more demanding challenge emerges if node mobility is considered. A moving node may lose registration with its current gateway, and may then need to register to a different gateway (a handover) to continue communicating. During a handover, any ongoing communication will be interrupted affecting network performance. In order to improve this performance, an IP mobility management protocol must be used. The main objective of this research is to develop a model that may be used to evaluate the performance of MANET handovers under different scenarios. Different issues about MANET integration with the Internet are considered: the IP mobility protocol implemented, the external route computation procedure, the type of ad hoc routing protocol used, and the gateway discovery approach used. For this evaluation, a mobile node in a MANET holding a communication with a correspondent node in the Internet roams to a different sub-network, having to change its registration to a different gateway. The different scenarios considered to evaluate the handover performance include the use of different types of MANET protocols, the use of different gateway discovery approaches, and the use of different versions of the Mobile IP protocol. During the research a review was made of the functioning conditions for the proposed scenario. Then, a handover model was proposed, which was used to develop some metrics that were later used to evaluate the MANET handover performance. This metrics are the broken communication time, the probability of handover failure, and the average communication interruption time. In all the results found, we could confirm that the proactive discovery approach has a better handover performance than the reactive discovery approach, which permit us to conclude that regardless the MANET routing protocol, and the Mobile IP version, the proactive agent discovery approach should be used in highly mobile scenarios, preferable, with the reactive routing protocol

    Survey on Quality Analysis of Collaboration Motivation Approach in Wireless Ad Hoc Networks

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    In Wireless Ad Hoc Networks (WANETs), tasks are conducted based on the cooperation of nodes in the networks. However, since the nodes are usually constrained by limited computation resources, selfish nodes may refuse to be cooperative. Reputation system is one of the main solutions to the node non cooperation problem. A reputation system evaluates node behaviours by reputation values and uses a reputation threshold to distinguish trustworthy nodes and untrustworthy nodes. Although this system has been widely used, very little research has been devoted to investigating the effectiveness of the node cooperation incentives provided by the systems. We propose a protocol called Enhanced Reverse Ad Hoc On Demand Vector Routing Protocol (ERAODV), which uses Hybrid Reputation System (HRS). A Hybrid Reputation system is an enhanced version of Classical Reputation System (CRS). Unlike the CRS it takes into account all the reputation values from the node to determine whether it is trustworthy or not. Keywords: WANET; Reputation System; Price Based System; Quality Analysis; Multipath Routing
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