Sharp approximate models of deflection routing in mesh networks

Deflection routing is a simple, decentralized, and adaptive method for routing data packets in communication networks. The focus of this work is on deflection routing in the Manhattan street network (a two-dimensional directed mesh), although the analytic approach should apply to any regular network. Two approximate performance models that give sharp estimates of the steady-state throughput and the average packet delay for packets admitted to the network are presented. The results of extensive simulation experiments are reported, which corroborate the models' predictions. The results show that deflection routing is very effective. Two measures of the merit of a network for deflection routing are its diameter and its deflection index. Networks are presented whose diameter and deflection index are near the optimal values     

Performance Evaluation of an All-Optical ShuffleNet using Optical Buffering and Deflection Routing

All-optical multihop networks, where the data portion of a packet is maintained in an optically encoded format from the source to the destination, can be achieved by augmenting optical switching nodes with optical buffering. Topologically, the ShuffleNet network is a strong contender for implementing such networks ranging from cluster networks to metropolitan area networks. The performance of a regular multihop network whose nodes are augmented with optical buffering and use deflection routing is evaluated. Using the ShuffleNet network as an example, we show that performance, in terms of throughput, average delay, and loss probability, can be improved as multiple fiber delay loops are added for a large range of network parameters. We then compare the performance of ShuffleNet with the Manhattan Street networks with similar features.     

规则全光分组网络中偏射路由算法的分析

就在ShuffleNet和Manhattan Street Network两种规则网络中使用偏射路由算法后的网络性能以及允许一个时隙插入多个数据包对该算法的影响进行了分析。结果说明，偏射路由算法不仅能使网络得到较高的性能，而且发挥了网状网具有迂回路由的能力。当采用允许插入多个数据包的策略时，网络的吞吐量和平均跳转次数都有小幅度的增加。     

采用偏射路由算法的全光分组网络的性能分析

本文提出采用统一的马尔可夫链方法分析存储转发路由和偏射路由算法的网络，并在具体计算偏射概率时，采用了递推的算法。着重分析了偏射路由算法在无存储器、有单个存储器及有两个存储器的情况下，ＭａｎｈａｔｔａｎＳｔｒｅｅｔＮｅｔｗｏｒｋ和ＳｈｕｆｌｅＮｅｔ网络的性能，包括网络吞吐量、数据包的平均跳转次数和数据包跳转次数的概率分布，并对ＭａｎｈａｔａｎＳｔｒｅｅｔＮｅｔｗｏｒｋ和Ｓｈｕｆ－ｆｌｅＮｅｔ两种网络进行了简单的比较。     

Analysis and comparison of hot-potato and single-buffer deflectionrouting in very high bit rate optical mesh networks

The steady state behavior of regular two-connected multihop networks in uniform traffic under a hot-potato and a simple single-buffer deflection routing technique is analyzed for very high bit rate optical applications. Manhattan Street Network and ShuffleNet are compared in terms of throughput, delay, deflection probability, and hop distribution both analytically and by simulation. It is analytically verified that this single-buffer deflection routing technique recovers in both networks more than 60% of the throughput loss of hot-potato with respect to store-and-forward when packets are generated with independent destinations. This gain, however, decreases to below 40% when the average message length exceeds 20 packets     

A comparison of linear and mesh topologies-DQDB and the Manhattanstreet network

The authors make a performance and reliability comparison of two networks that have been proposed for use as high-speed metropolitan area networks (MANs)-the Manhattan street network (MSNet) and the distributed queue dual bus (DQDB) network. Both networks use slotted access protocols and have the same number of links, transmitters, and receivers per node. The DQDB network has been adopted by the IEEE 802.6 committee as the metropolitan area network (MAN) standard. The authors demonstrate the relative superiority of the MSNet over the DQDB network. They show that the MSNet provides a much higher network throughput for a variety of traffic patterns-uniform and nonuniform. They also look at the reliability of both networks and show that the MSNet can survive more failures than the DQDB network and that failures cause a lesser performance degradation in the MSNet. It is also shown that higher-level mechanisms are required in the DQDB network to recover from link failures whereas deflection routing is sufficient in the MSNet     

Analysis of a dual-receiver node with high fault tolerance forultrafast OTDM packet-switched shuffle networks

In this paper, we present a high-performance dual-receiver transparent optical node configuration suitable for two-connected multihop transparent optical networks operating at ultrafast bit rates. The steady-state behavior of optical shuffle networks is analyzed with this configuration and a minimum-loss node configuration. Deflection routing is employed as the means for contention resolution. Both analytical results and simulation results are presented on the network performance in terms of network throughput and delay. We also propose modified routing schemes for network fault tolerance. Applying both store-and-forward and deflection routing techniques, the networks can operate without packet loss in the presence of faults     

Deflection routing in hypercube networks

An approximate analysis of the transient and steady state behavior of deflection routing in hypercube networks is presented, under a uniform traffic model. In deflection routing congestion causes packets admitted to the network to be temporarily misrouted rather than buffered or dropped. The approximations show that deflection routing performs remarkably well in hypercube networks, for small as well as large networks and for the whole range from light to heavy load. Simulations suggest that the approximations are quite accurate     

BanyanNet-a bidirectional equivalent of ShuffleNet

A multihop, wavelength division multiplex (WDM) based network, BanyanNet, is proposed for the realization of terabit lightwave networks, BanyanNet can he considered as a the bidirectional equivalent of the popular ShuffleNet. Exploiting its representation, we developed a fast, decentralized, bidirectional routing algorithm for BanyanNet. The performance of BanyanNet is compared to that of the ShuffleNet and bilayered ShuffleNet. For N=p^m×k networks, the p=2 BanyanNet provides better performance in channel efficiency, total and user throughput than the corresponding ShuffleNet, and offers more flexible network configurations than the bilayered and p=4 ShuffleNet     

Economic analysis of robust access network architecture in two-tierdata networks

Recent studies have addressed routing and performance issues of nonhierarchical and hierarchical backbone packet networks in a unified fashion, by adopting an end-to-end mean delay objective and including a variety of practical routing constraints. The authors build on this approach to include the design of robust access networks, and they analyze the economic and robustness-related tradeoffs of several access network architectures in two-tier data packet networks. Two-tier architectures consist of an access network that homes to a high-capacity backbone network through a variety of topological arrangements. The access tier provides protocol handling and traffic concentration. The backbone tier performs high-speed transport and alternate routing under congestion/failure conditions. They identify the fundamental access network parameters that allow them to develop network designs with optimized characteristics. The analysis demonstrates the cost effectiveness of access diversity as well as the enhanced robustness it can provide even though it requires higher switch functionality and cost     

Performance Analysis of an Optical Switched Manhattan Street Network

Manhattan Street Networks (MSN) are bidimensional linear node sets arranged as the avenues and streets of Manhattan. Deflection routing is performed –either in the synchronous or in the asynchronous mode–by conveying incoming packets towards one of the two outputs. The simulation and analysis of all-optical MS networks is the central target of this paper. In order to avoid using complex electronics and/or optical domain buffers, the deflection routing and the asynchronism are taken into account in the analysis. The obtained results are compared and discussed with respect to some previously described analytic methodologies.     

The multi-copy diversity for routing in sparse vehicular ad hoc networks

The need for routing based on store-and-carry forwarding has been motivated in sparse vehicular ad hoc networks (VANETs), since the traditional end-to-end unicast routing is infeasible due to the network disconnection problem. In store-and-carry based routing, the end-to-end message delivery delay is dominated by the store-and-carry procedure rather than the wireless transmission. Therefore, the end-to-end delay in such sparse VANETs can be further reduced by replicating multiple copies of the message to other nodes when possible, i.e., multi-copy routing, to increase the chance of finally finding the destination, which we call this gain as multi-copy diversity. In this paper, we present an analytic framework to evaluate the performance of routing by assessing the multi-copy diversity gain in sparse VANETs. By using this model, we first derive an upper and lower-bound of end-to-end routing delay in sparse VANETs. Our analytic results show that a high level of multi-copy diversity gain is achieved when the network is partially connected, which is in contrast to the conventional expectation that multi-copy routing performs better in severely disconnected networks. Second, we propose a new adaptive multi-copy VANET routing scheme called AMR by exploiting these analytic results. AMR adapts to the local network connectivity and increases the level of multi-copy diversity at significantly reduced routing overhead compared to the well known epidemic routing. We validate the accuracy of our analytic model and the performance of AMR via simulation studies.     

Contention-Based Limited Deflection Routing Protocol in Optical Burst-Switched Networks

Optical burst switching (OBS) is a very promising switching technology for realization of an economical optical Internet. In OBS networks, when contention occurs at an intermediate switch, two or more bursts that are in contention can be lost because a forwarding path reservation is not made for a burst until a control message for the burst arrives. That is the reason why one of the critical design issues in OBS is finding ways to minimize burst dropping resulting from resource contention. In this paper, we propose and analyze a novel deflection routing protocol, which mitigates and resolves contention with significantly better performance as compared with techniques currently known in the literature. While several variants of the basic deflection routing scheme have been proposed before, they all lacked the ability to determine the alternate route based on clear performance objectives. In this paper, we present an on-demand deflection routing scheme, which sequentially performs the following: 1) based on certain performance criteria, dynamically determines if the burst should be deflection routed or retransmitted from source and 2) if the decision is to deflection route, then the same is done using a path that is based on minimization of a performance measure that combines distance and blocking due to contention. The proposed contention-based limited deflection routing scheme prevents injudicious deflection routing. Our simulation results show that the scheme proposed here has much superior performance both in terms of burst loss probability and increased network throughput. Through analytical and simulation modeling, a number of useful insights into the OBS network protocols and performance are provided.     

Nonlinear BER performance of dense optical WDM manhattan street network with deflection routing

The nonlinear bit-error-rate (BER) performance of dense optical wavelength-division-multiplexed (WDM) Manhattan Street Networks with deflection routing was evaluated using an extendable semianalytical process. The results show that nonlinear effects impose significant performance penalties on dense WDM networks, both in terms of maximum hops attainable and average BER, and should be taken into account when modeling such networks. Simple techniques such as optimal amplifier positioning can reduce the nonlinear penalties.     

光分组交换网中的一种新模型

目前常用的网络理论模型如曼哈顿网络、洗牌网等均不能适应光分组网络研究的需要.文章提出了一种新的光网络模型———自相似环流网状网.该模型特别适合于光分组网络的研究.文章还研究了该模型的许多特性.     

一种新型的ShuffleNet多跳等效时分复用网络

文章介绍了多跳网(ShuffleNet)的结构和路由算法,提出了一种新型的ShuffleNet等效时分复用网络,给出了该网络结构的路由算法,并对8节点的基于光时分复用的ShuffleNet等效网络性能进行了分析。     

An SDN approach to route massive data flows of sensor networks

With the advent of the Internet of Things (IoT), more and more devices can establish a connection with local area networks and use routing protocols to forward all information to the sink. But these devices may not have enough resources to execute a complex routing protocol or to memorize all information about the network. With proactive routing protocols, each node calculates the best path, and it needs enough resources to memorize the network topology. With reactive routing protocols, each node has to broadcast the message to learn the right path that the packets must follow. In all cases, in large networks such as IoT, this is not an appropriate mechanism. This paper presents a new software‐defined network (SDN)–based network architecture to optimize the resource consumption of each IoT object while securing the exchange of messages between the embedded devices. In this architecture, the controller is in charge of all decisions, and objects only exchange messages and forward packets among themselves. In the case of large networks, the network is organized into clusters. Our proposed network architectures are tested with 1000 things grouped in five clusters and managed by one SDN controller. The tests using OpenDayLight and IoT embedded applications have been implemented on several scenarios providing the ability and the scalability from dynamic reorganization of the end‐devices. This approach explores the network performance issues using a virtualized SDN‐clustered environment which contributes to a new model for future network architectures.     

Multistar implementation of expandable ShuffleNets

ShuffleNet is one of the many architectures proposed for multihop lightwave networks. Its advantages include low mean-internodal distance and simple routing. Modular growth of ShuffleNets, however, is generally difficult and requires many hardware and software reconfigurations. The authors consider a multistar implementation of ShuffleNet and discuss how a (p,k) ShuffleNet can be expanded to a (p,k+1) ShuffleNet in modular phases, where each phase increases the number of nodes by only a small fraction and requires only minor hardware and software reconfigurations     

自相似环流网状网性能分析

文章对自相似环流网状网的路由协议做了研究,提出了两种选路算法,并且对自相似环流网状网的性能指标(阻塞率与时延)做了仿真分析,并将仿真结果与根据Manhattan网络模型得到的结果做了对比和分析.结果表明我们的模型比曼哈顿街区网(MSN)模型更适合于光分组交换网络.     

Reliability and performance evaluation of four tree multistage interconnection network

Reliability and performance of a multiprocessor system depend heavily upon the design of its interconnection network. This paper presents a comprehensive treatment to analyse a four tree network, a new class of irregular multistage interconnection networks (MIN), for reliability and performance. The results obtained are compared with the augmented shuffle exchange network (ASEN), a network with low link and switch complexity and having significantly improved reliability and performance amongst the regular type of MINs. The reliability results, both optimistic and pessimistic, are better than for the ASEN as well as for most of the other networks. The performance analysis in the circuit switched environment shows that the probability of accepting the requests is significantly improved and there is negligible degradation in performance with increasing network size.