Link failure resilience in the dynamic source routing protocol

Reactive routing protocols for mobile ad hoc networks reduce the routing cost in high mobility environments where link failures are frequent. However, route discovery in these protocols is typically performed via network‐wide flooding, which consumes a substantial amount of bandwidth and causes a significant latency to data packets. To improve the dynamic source routing (DSR) protocol and overcome these limitations, we propose two optimization techniques, viz. generalized salvaging mechanism and cache maintenance using a distributed topology discovery mechanism through mobile ant‐agents. We show, by simulations, that our contributions improve the DSR performance, and particularly in large scale networks with high mobility and heavy load that cause frequent link failures. Copyright © 2008 John Wiley & Sons, Ltd.     

Distributed dynamic routing schemes

Schemes that do not explicitly use much information about the state of networks are briefly surveyed, with the focus on dynamic alternative routing (DAR), a simple but highly effective routing method currently planned for the British Telecom Network. State-dependent routing and how some of the methodology also has bearing on the control issue are discussed. The problem of dimensioning a network that uses dynamic routing (i.e. how much capacity is needed and where it should be put to provide an acceptable performance) is addressed. A practical example, which refers to routing in an international access network, is discussed. Some conclusions are drawn on the benefits and drawbacks of distributed routing     

Ad-hoc网络上的动态路由协议研究及实现

概要介绍了Ad-hoc网络的概念。通过分析其网络特点,描述了该种网络对动态路由协议的要求。简要介绍了当前流行的几种Ad-hoc动态路由协议及特点。详细描述了OLSR路由协议的术语和主要思想。最后结合工程实践,介绍了实现该协议过程中的关键问题,并在模拟网络环境下验证了该协议的正确性。     

A dynamic cross-layer routing protocol for Mobile Ad hoc Networks

A new cross-layer routing protocol, named Dynamic Packet Guidance (DPG), is introduced for Mobile Ad hoc Networks (MANETs). Simulation results show that DPG is quite useful for usage in dense networks of mobile nodes, with medium-to-high speeds, and low-to-medium load. In these scenarios, DPG provides a superior performance compared to several well-known ad hoc routing protocols. The low end-to-end delay and smaller overhead that DPG achieves in such scenarios positively impacts the scalability of MANETs and reduces the energy requirements of nodes in such networks. DPG also shows immunity to failing nodes, as it operates consistently almost independently of failing nodes up to a certain ratio.     

Distributed quality of service routing protocol for multimedia traffic in WiMedia networks

Ultra-wideband (UWB) technology has emerged as a solution for the wireless interface between medical sensors and personal servers in future telemedicine systems. The WiMedia Alliance has specified a distributed medium access control protocol based on UWB for high-rate WPANs. In the cases of some applications, data traffic between the source device and destination device is transmitted via one or more intermediate links before it reaches the destination device. However, when all data frames do not transmit in the current DRP reservation block, a relay device cannot transmit the received data frame from the source device in the current DRP policy, until the next DRP duration reserved for forwarding to the destination device begins. This policy increases end-to-end latency between the source device and destination device significantly. Therefore, in this paper, we propose a novel reservation-based routing protocol to minimize the end-to-end delay between source and destination. The proposed routing protocol utilizes the number of medium access slots and hop-count to decide the optimal route between the source device and destination device. The simulation results show that the proposed protocol can enhance the throughput and delay performance and improve energy efficiency by minimizing the packet drop and collision.     

无线网络的多径源路由协议研究

对目前AdHoc无线移动网络中存在的路由问题进行分析，并从多路径路由的要求出发，讨论把动态源路由协议DSR改造成多源路径协议的可行性，并提出了具体的实现算法。文中所提出的多径源路由协议为无线网络的路由协议的研究提供了重要的理论支持。     

基于LSTM模型的动态转发路由协议

文中将容忍延迟网络(Delay Tolerant Network,DTN)应用于船舶通信,提出了一种基于长短时记忆网络(Long Short-Term Memory,LSTM)模型的动态转发路由协议LSTM-DRA(Dynamic Distri-bution Routing Algorithm Based on LST...     

一种基于动态概率转发的AODV路由协议

在Ad hoc网络(自组织网络)的路由建立过程中,由于AODV(Ad hoc按需距离矢量)路由采用洪泛方式转发RREQ(路由请求)消息会产生很多不必要的重传,很可能引发广播风暴而影响网络性能。文章提出了一种基于动态概率转发RREQ消息的改进方案,该方案根据邻居节点的个数选择不同的概率转发RREQ消息。仿真结果表明,在网络节点较多且网络比较稠密的情况下,改进方案能有效减少网络端到端时延,提高网络吞吐量和分组投递率。     

无线网络的多径源路由协议研究

对目前Ad Hoc无线移动网络中存在的路由问题进行分析,并从多路径路由的要求出发,讨论把动态源路由协议DSR改造成多源路径协议的可行性,并提出了具体的实现算法.文中所提出的多径源路由协议为无线网络的路由协议的研究提供了重要的理论支持.     

基于动态分区的无线传感器网络非均匀成簇路由协议简

针对节点负载不均而形成的“热区”问题,提出了一种基于动态分区负载均衡的分布式成簇路由协议(UCDP)。其核心思想是：将网络合理化地动态分区,使距离基站较近的区面积较小,从而减少需要承担转发任务节点的区内通信开销,节省更多的能量供数据转发使用;综合考虑距离因子和剩余能量因子进行区内非均匀成簇;有机结合簇内单跳和区间转发,区头与簇头共同协作进行路由传输。实验表明,协议具有较好的稳定性,显著延长了网络的生存周期。     

SRDP: Secure route discovery for dynamic source routing in MANETs

Routing is a critical function in multi-hop mobile ad hoc networks (MANETs). A number of MANET-oriented routing protocols have been proposed, of which DSR is widely considered both the simplest and the most effective. At the same time, security in MANETs – especially, routing security – presents a number of new and interesting challenges. Many security techniques geared for MANETs have been developed, among which Ariadne is the flagship protocol for securing DSR.The focus of this work is on securing the route discovery process in DSR. Our goal is to explore a range of suitable cryptographic techniques with varying flavors of security, efficiency and robustness. The Ariadne approach (with TESLA), while very efficient, assumes loose time synchronization among MANET nodes and does not offer non-repudiation. If the former is not possible or the latter is desired, an alternative approach is necessary. To this end, we construct a secure route discovery protocol (SRDP) which allows the source to securely discover an authenticated route to the destination using either aggregated message authentication codes (MACs) or multi-signatures. Several concrete techniques are presented and their efficiency and security are compared and evaluated.     

Minimum energy hierarchical dynamic source routing for Mobile Ad Hoc Networks

In this paper, Minimum Energy Dynamic Source Routing (MEDSR) and Hierarchical Minimum Energy Dynamic Source Routing (HMEDSR) protocols for Mobile Ad Hoc Networks (MANET) are proposed. The objective of MEDSR protocol is to reduce energy consumption in MANET while maintaining connectivity in the network. The objective of HMEDSR is to reduce the overhead of MEDSR. The overall result is that energy spent in transmitting overhead packets is reduced. This reduction allows more energy in transmitting data packets. The Dynamic Source Routing (DSR) protocol is modified to implement both MEDSR and HMEDSR protocols, and these implementations are tested with a network simulator (Network Simulator (NS-2)). The simulation results show that both MEDSR and HMEDSR protocols reduce energy consumption per data packet by 25% compared to DSR, but HMESDR further reduces energy consumption by 12% compared to MEDSR by controlling overhead packets.     

Summary cache: a scalable wide-area Web cache sharing protocol

The sharing of caches among Web proxies is an important technique to reduce Web traffic and alleviate network bottlenecks. Nevertheless it is not widely deployed due to the overhead of existing protocols. In this paper we demonstrate the benefits of cache sharing, measure the overhead of the existing protocols, and propose a new protocol called “summary cache”. In this new protocol, each proxy keeps a summary of the cache directory of each participating proxy, and checks these summaries for potential hits before sending any queries. Two factors contribute to our protocol's low overhead: the summaries are updated only periodically, and the directory representations are very economical, as low as 8 bits per entry. Using trace-driven simulations and a prototype implementation, we show that, compared to existing protocols such as the Internet cache protocol (ICP), summary cache reduces the number of intercache protocol messages by a factor of 25 to 60, reduces the bandwidth consumption by over 50%, eliminates 30% to 95% of the protocol CPU overhead, all while maintaining almost the same cache hit ratios as ICP. Hence summary cache scales to a large number of proxies. (This paper is a revision of Fan et al. 1998; we add more data and analysis in this version.)     

Distributed routing for load balancing

Some open-loop and closed-loop control algorithms are discussed for an example of a discrete-event system, namely, the routing of arriving tasks from different arrival streams among several possible service stations. It is shown that it is possible to design open-loop policies that give good performance in a way which is very robust with respect to large changes in the arrival rates. This is possible even though it is assumed that there is no online coordination between the routing algorithms for the different arrival streams. Some further improvements of the performance are possible when a simple feedback policy, namely, overflow routing, is implemented. This also gives reasonable robustness of performance with respect to changes in the service rates     

面向高动态高空平台网络的路由协议研究

提出了一种面向高动态高空平台网络的路由协议,该协议通过按需查找方式确定高动态用户所属的高空平台,根据最短延时路由表在高空平台之间转发数据,并通过用户切换策略保证数据传输的连续性。仿真结果表明,该协议能够适应用户高速移动和频繁切换的高动态环境,具有可靠性高、延时小、路由开销小、抗毁性强等特点,为高动态高空平台网络的数据转发提供了一种可行的解决方法。     

Analysis of MANET dynamic source routing and its performance enhancements

Since the inception of the dynamic source routing (DSR) protocol for mobile ad hoc networks, several enhancements have been proposed, along with other competing routing protocols. All of them provide different degrees of throughput improvement under different scenarios. In this paper, we use DSR as a base, diagnose the contribution of its constituent components, and provide the reason why certain routing enhancements can increase the throughput and under what conditions. A major finding of the study is that the broadcast mechanism used in propagating route request and route error messages has a significant impact on how routing behaves. We also show that unicast route error report and preventive cache update improve throughput at different sides of the mobility spectrum. Finally, we show that aggressive buffer combined with route management provides the best performance improvement on the entire mobility and loading spectrum. Copyright © 2013 John Wiley & Sons, Ltd.     

Location-aware routing protocol with dynamic adaptation of request zone for mobile ad hoc networks

One possibility direction to assist routing in Mobile Ad Hoc Network (MANET) is to use geographical location information provided by positioning devices such as global positioning systems (GPS). Instead of searching the route in the entire network blindly, position-based routing protocol uses the location information of mobile nodes to confine the route searching space into a smaller estimated range. The smaller route searching space to be searched, the less routing overhead and broadcast storm problem will occur. In this paper, we proposed a location-based routing protocol called LARDAR. There are three important characteristics be used in our protocol to improve the performance. Firstly, we use the location information of destination node to predict a smaller triangle or rectangle request zone that covers the position of destination in the past. The smaller route discovery space reduces the traffic of route request and the probability of collision. Secondly, in order to adapt the precision of the estimated request zone, and reduce the searching range, we applied a dynamic adaptation of request zone technique to trigger intermediate nodes using the location information of destination node to redefine a more precise request zone. Finally, an increasing-exclusive search approach is used to redo route discovery by a progressive increasing search angle basis when route discovery failed. This progressive increased request zone and exclusive search method is helpful to reduce routing overhead. It guarantees that the areas of route rediscovery will never exceed twice the entire network. Simulation results show that LARDAR has lower routing cost and collision than other protocols. Tzay-Farn Shih was with Department of Electrical Engineering, National Taiwan University. Tzay-Farn Shih received the B.S. degree in Information Management from Chinese Culture University, Taiwan, in 1992, the M.S. degree in Computer Science Engineering from Tatung University, Taiwan, in 1996, and the Ph.D. degree in Electrical Engineering from National Taiwan University, Taiwan, in 2006. He is presently an assistant professor of Computer Science and Information Engineering at Chaoyang University of Technology, where he initially joined in August 2006. He is currently an overseas member of the Institute of Electronics, Information and Communication Engineers (IEICE). His current research interests include computer simulation, computer networks routing protocol, wireless networks, Mobile Ad Hoc networks and sensor networks. Hsu-Chun Yen was born in Taiwan, Republic of China, on May 29, 1958. He received the B.S. degree in electrical engineering from National Taiwan University, Taiwan, in 1980, the M.S. degree in computer engineering from National Chiao-Tung University, Taiwan, in 1982, and the Ph.D. degree in computer science from the University of Texas at Austin, U.S.A., in 1986. He is presently a Professor of Electrical Engineering at National Taiwan University, where he initially joined in August 1990. From August 1986 to July 1990, he was an Assistant Professor of Computer Science at Iowa State University, Ames, Iowa, U.S.A. His current research interests include Petri net theory, formal methods, design and analysis of algorithms, and complexity theory. Dr. Yen is an editor of International Journal of Foundations of Computer Science (IJFCS, World Scientific Publisher).     

A topology-oblivious routing protocol for NDN-VANETs

Vehicular Ad Hoc Networks (VANETs) are characterized by intermittent connectivity, which leads to failures of end-to-end paths between nodes. Named Data Networking (NDN) is a network paradigm that deals with such problems, since information is forwarded based on content and not on the location of the hosts. In this work, we propose an enhanced routing protocol of our previous topology-oblivious Multihop, Multipath, and Multichannel NDN for VANETs (MMM-VNDN) routing strategy that exploits several paths to achieve more efficient content retrieval. Our new enhanced protocol, i mproved MMM-VNDN (iMMM-VNDN), creates paths between a requester node and a provider by broadcasting Interest messages. When a provider responds with a Data message to a broadcast Interest message, we create unicast routes between nodes, by using the MAC address(es) as the distinct address(es) of each node. iMMM-VNDN extracts and thus creates routes based on the MAC addresses from the strategy layer of an NDN node. Simulation results show that our routing strategy performs better than other state of the art strategies in terms of Interest Satisfaction Rate, while keeping the latency and jitter of messages low.     

一种"北斗"导航星座数据上注的动态链路树路由方法

针对目前“北斗”导航系统星间链路维护中频繁进行的时隙表、路由表等数据上注耗时较长的问题,利用星座各星上注数据一致的特点,提出了一种“北斗”导航星座数据上注的动态链路树路由方法。该方法能够显著降低整个星座数据上注过程的资源占用,并较大幅度地提高完成数据上注任务速度,缩短数据上注的时间。     

Distributed multicast routing for delay-sensitive applications

A distributed multicast algorithm for constructing minimum cost multicast trees with delay constraints is proposed. The proposed algorithm can always construct a delay-constrained multicast tree, if one exists, and exhibits superior tree cost performance compared to existing algorithms