Deflection routing in IP optical networks

This paper deals with optical packet switching in a full-IP transport network scenario. Given the technological limits of accomplishing packet buffering in the optical domain, deflection routing is here explored as an alternative technique for resolving packet contentions without buffering packets. Two different network topologies have been considered here, that is a regular six-node network with different connectivity factors and the classical NSF network. A limited amount of optical buffering is considered in the switching nodes that performs both input queuing and shared queuing of packets to be switched. The performance improvements that can be obtained by deflection routing have been evaluated considering different methods for choosing the alternative paths where to deflect packets that cannot be transmitted onto the shortest path to the addressed destination.     

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     

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。     

Packet scheduling algorithms and performance of a bufferedshufflenet with deflection routing

In a multihop network, packets go through a number of hops before they are absorbed at their destinations. In routing to its destination using minimum path, a packet at a node may have a preferential output link (the so-called “care” packet) or may not (the so-called “don't care” packet). Since each node in an optical multihop network may have limited buffer, when such buffer runs out, contention among packets for the same output link can be resolved by deflection. In this paper, we study packet scheduling algorithms and their performance in a buffered regular network with deflection routing. Using shufflenet as an example, we show that high performance (in terms of throughput and delay) can he achieved if “care” packets can be scheduled with higher priority than “don't care” packets. We then analyze the performance of a shufflenet with this priority scheduling given the buffer size per node. Traditionally, the deflection probability of a packet at a node is solved from a transcendental equation by numerical methods which quickly becomes very cumbersome when the buffer size is greater than one packet per node. By exploiting the special topological properties of the shufflenet, we are able to simplify the analysis greatly and obtain a simple closed-form approximation of the deflection probability. The expression allows us to extract analytically the performance trend of the shufflenet with respect to its buffer and network sizes. We show that a shufflenet indeed performs very well with only one buffer, and can achieve performance close to the store-and-forward case using a buffer size as small as four packets per node     

Information routing and reliability issues in distributed sensornetworks

Communication issues and problems in information routing in distributed sensor networks (DSNs) are considered. Two important communication constraints, viz., the delay constraint and the reliability constraint, are identified, and their impact on information routing is discussed. It is shown that the maximum end-to-end delay in a network depends on the diameter of the network, and efficient distributed algorithms are presented to determine the diameter of asynchronous networks. A distributed algorithm that determines the diameter of an asynchronous tree network when an arbitrary node in the network initiates the algorithm is introduced. An efficient algorithm for determining the diameter when multiple nodes initiate the algorithm is presented. An algorithm to determine the diameter of arbitrary networks is presented, and its message complexity is shown. Effects of link/node failures on network delay are studied, and important network structure design criterion are discussed. The distributed, dynamic routing algorithms are reviewed, and their adaptation to DSN environments is discussed     

The Data Vortex Optical Packet Switched Interconnection Network

A complete review of the data vortex optical packet switched (OPS) interconnection network architecture is presented. The distributed multistage network topology is based on a banyan structure and incorporates a deflection routing scheme ideally suited for implementation with optical components. An implemented 12-port system prototype employs broadband semiconductor optical amplifier switching nodes and is capable of successfully routing multichannel wavelength-division multiplexing packets while maintaining practically error-free signal integrity (BER $ ≪ {hbox{ 10}}^{ - 12}$ ) with median latencies of 110 ns. Packet contentions are resolved without the use of optical buffers via a distributed deflection routing control scheme. The entire payload path in the optical domain exhibits a capacity of nearly 1 Tb/s. Further experimental measurements investigate the OPS interconnection network's flexibility and robustness in terms of optical power dynamic range and network timing. Subsequent experimental investigations support the physical layer scalability of the implemented architecture and serve to substantiate the merits of the data vortex OPS network architectural paradigm. Finally, modified design considerations that aim to increase the network throughput and device-level performance are presented.      

A performance model of deflection routing in multibuffer networkswith nonuniform traffic

Deflection routing can be used in networks whose stations have the same number of input and output links. Fixed length packets arrive synchronously on the station's input links at the beginning of time slots, and each packet is routed via the output link that offers the shortest path to its destination. Since the number of packet buffers at each output link is finite, the simultaneous contention of two packets for the last buffer of a common output link must be resolved by “deflecting” one of the packets to another output link. Thus, the deflection of a packet could result in the packet following a route that is not a shortest path. The potentially unbounded number of routes that a given packet can take makes analyzing the performance of such networks difficult. In particular, there are no analytical models that can analyze multibuffer deflection-routing networks with nonuniform traffic. Using independence assumptions, the authors develop a performance model of deflection routing that allows to estimate accurately and efficiently the mean transport time and throughput in a network that has any given two-connected topology, multiple buffers at each output port, and an arbitrary traffic matrix     

OBS网络的偏射路由研究

文章分析了偏射路由对网络性能的影响,在分析发送端控制偏射路由技术的基础上,提出了基于阈值检测和数据更新的改进方案.边缘节点快速更新状态信息,并通过特殊控制分组传递链路拥塞的分布特征等信息;交换节点进行阈值检测,动态决定竞争时突发的传送方式,减少偏射路由对网络负荷的影响,进一步降低网络阻塞率,改善网络性能。     

OBS网络中基于拥塞避免的提前偏射路由研究

突发竞争是OBS(光突发交换)网络需要解决的关键问题,偏射路由作为一种有效的竞争解决方案而被广泛研究。文章提出了一种基于拥塞避免的提前偏射路由算法,利用周期性反馈的网络拥塞信息按一定概率提前偏射部分突发包。与传统的最短偏射路由算法相比,本算法达到了避免拥塞以及均衡网络负载的目的。仿真结果表明:文章所提算法在突发丢失率、吞吐量以及平均链路利用率方面性能都有所提高。     

A Class of Decentralized Routing Algorithms Using Relaxation

An important problem in packet-switched communication networks is the optimal assignment of routes to the message packets. An optimal routing assignment is one which chooses network paths for the packets in a way that minimizes some cost function, typically average message delay. A class of optimal routing algorithms is described which utilize a type of iterative computation known as relaxation. Computation is decentralized in the sense that each node computes its routing strategy using only information supplied from adjacent nodes. Being iterative, the algorithms are inherently adaptive. The routing computation is based conceptually on an electrical network analog for the optimization problem. We show that a simple, convergent relaxation procedure can be used to "solve" the analog network, thereby yielding the optimal routing strategy. A simple example is presented to illustrate the method. In general, the computational load compares favorably with other (centralized) methods, although further work is needed to obtain quantitive comparisons in specific cases.     

Routing for multimedia traffic in wireless frequency-hopcommunication networks

A new method is described for routing multimedia traffic in a frequency-hop (FH) store-and-forward packet radio network. The method is illustrated for traffic of two types, each type having its own throughput, delay, and error-rate requirements. A typical application is the routing of voice and data packets in a distributed multiple-hop network. In such an application, voice packets cannot tolerate much delay, but they are allowed to contain a small number of frame erasures while data packets must be delivered error-free even if a moderate delay is required to do so. The fully distributed routing protocol presented in the paper takes into account the type of service required for each type of traffic, and it adapts to the interference as seen by the FH radio receivers in the network. Our approach to multimedia routing is based on least-resistance routing with different link and path resistance metrics for different message types. Each of the resistance metrics for a link reflects the ability of the link to provide the service required by the one of the message types. This includes, but is not limited to, a measure of the likelihood of successful reception by the FH radio receiver for that link. The route selection for a particular type of packet depends on the resistances of the links along the routes from that packet's source to its destination. In general, different routes may be selected for different types of packets. The primary conclusion of this paper is that the quality of service increases for each of the two types of multimedia traffic if the routing protocol accounts for the type of message that is being relayed     

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     

Datagram authentication in internet gateways: implications of fragmentation and dynamic routing

The implications of fragmentation and dynamic routing for datagram authentication at the gateway level are discussed. Two protocols are presented that permit varying degrees of fragmentation and dynamic routing, while allowing the gateways to authenticate successive packets belonging to authorized connections. The first adapts to changing paths and fragmentation by keeping state information on a per-packet basis, while the second restricts fragmentation but incurs little state overhead. The two methods vary in implementation complexity, overhead, number of extra packets sent, and host modification requirements. They were designed with different network characteristics in mind, and, since they are not mutually exclusive, both can be incorporated and used depending on the nature of communication.<>     

Security upgrade against RREQ flooding attack by using balance index on vehicular ad hoc network

VANET is an ad hoc network that formed between vehicles. Security in VANET plays vital role. AODV routing protocol is a reactive or on-demand routing protocol which means if there is data to be send then the path will create. AODV is the most commonly used topology based routing protocol for VANET. Using of broadcast packets in the AODV route discovery phase caused it is extremely vulnerable against DOS and DDOS flooding attacks. Flooding attack is type of a denial of service attack that causes loss of network bandwidth and imposes high overhead to the network. The method proposed in this paper called Balanced AODV (B-AODV) because it expects all network node behave normally. If network nodes are out of the normal behavior (too much route request) then they identified as malicious node. B-AODV is designed with following feature: (1) The use of adaptive threshold according to network conditions and nodes behavior (balance index) (2) Not using additional routing packets to detect malicious nodes (3) Perform detection and prevention operations independently on each node (4) Perform detection and prevention operations in real time (5) No need for promiscuous mode. This method for detection and prevention flooding attack uses average and standard deviation. In this method each node is employing balance index for acceptation or rejection RREQ packets. The results of the simulation in NS2 indicates B-AODV is resilience against flooding attack and prevent loss of network bandwidth. Comparing between AODV with B-AODV in normal state (non-attacker) shows B-AODV is exactly match with AODV in network performance, this means that the B-AODV algorithm does not impose any overhead and false positive to AODV.     

Comparison of two recycle dilated banyan network with outputbuffers

Two dilated banyan networks with circulation and deflection routing algorithm are proposed. Without input buffers, the proposed switching fabrics can fully reuse the routing capacity wasted in a pure dilated banyan network. An analytical model of two switching fabrics and a study of packet loss probability are presented     

基于网络编码的机会网络高效路由算法

针对采用Epidemic机制的机会网络路由算法在数据分组传送阶段存在通信冗余的问题,提出了一种基于网络编码的高效路由算法--NCBER(network-coding-based epidemic routing）。NCBER在传送数据分组的过程中使用主动异或网络编码和多播,并取消了 Request（请求）控制分组,从而减少数据分组的转发次数和控制分组数量,降低网络开销,缩短分组传输时延。理论分析和仿真结果表明,NCBER 算法在网络开销和数据分组端到端时延性能方面优于经典的Epidemic路由算法及其改进算法MRRMR（message redundancy removal of multi-copy routing）,并且使数据传送成功率保持在100%。     

Link State Routing Based on Compressed Sensing

In table routing protocols such as link state routing, every node in the network periodically broadcasts its link state and the state of its neighbors. These routing updates result in the transmission of a large number of packets. Some of these packets contain correlated or even redundant data which could be compressed if there is central management in the network. However, in autonomous networks, each node acts as a router, in which case central coordination is not possible. In this paper, compressed sensing is used to reduce routing traffic overhead. This can be done at nodes which have greater processing capabilities and no power consumption limitations such as backbone nodes in wireless mesh networks. A method is proposed to select a subset of nodes and thus a subset of links to probe their state. The sensed states are encoded to generate a low dimension sampled vector. This compressed link state vector is broadcast to the entire network. Nodes can then reconstruct link states from this vector using side information. Performance results are presented which demonstrate accurate anomaly detection while adapting to topology changes. Further, it is shown that a proper choice of weighting coefficients in the sampling process can improve detection performance.     

Differentiated contention resolution for QoS in photonic packet-switched networks

Packet contention is a major challenge in photonic packet-switched networks due to the lack of random access buffers in the optical domain. Existing contention resolution approaches such as wavelength conversion and fiber-delay-line buffering may significantly increase the overall system cost and may be difficult to implement. To avoid such issues, this paper proposes a framework for providing label-based differentiated contention resolution by exploiting recirculation buffering and deflection routing. To accommodate more options for differentiation and to avoid the potential problem of forwarding packets in a network indefinitely, two classes of loopless deflection algorithms are provided. An analytical model is also developed to evaluate the packet loss probability and the end-to-end delay for different buffering and deflection routing schemes. The paper also investigates the effectiveness of the control schemes in providing differentiated loss and delay through simulation and analysis. The accuracy of the analytical model is confirmed by simulation.     

Location aided probabilistic broadcast algorithm for mobile Ad-hoc network routing

On-demand routing protocols are widely used in mobile Ad-hoc network (MANET). Flooding is an important dissemination scheme in routing discovering of on-demand routing protocol. However, in high-density MANET redundancy flooding packets lead to dramatic deterioration of the performance which calls broadcast storm problem (BSP). A location-aided probabilistic broadcast (LAPB) algorithm for routing in MANET is proposed to reduce the number of routing packets produced by flooding in this paper. In order to reduce the redundancy packets, only nodes in a specific area have the probability, computed by location information and neighbor knowledge, to propagate the routing packets. Simulation results demonstrate that the LAPB algorithm can reduce the packets and discovery delay (DD) in the routing discovery phase.     

Performance of hypercube routing schemes with or without buffering

Considers two different hypercube routing schemes, which are called the simple and the priority schemes. The authors evaluate the throughput of both the unbuffered and the buffered version of these schemes for random multiple node-to-node communications. The results obtained are approximate, but very accurate as simulations indicate, and are given in particularly interesting forms. They find that little buffer space (between one and three packets per link) is necessary to achieve throughput close to that of the infinite buffer case. They also consider two deflection routing schemes, called the simple nonwasting deflection and the priority nonwasting deflection schemes. They evaluate their throughput-using simulations, and compare them to the priority scheme