紧凑路由研究

传统的最短路径路由策略通常需要在每个节点上维护到所有其他节点的路由信息,路由表大小随着网络规模的增加而快速增长,因此可扩展性不好.紧凑路由能够有效降低路由表的增长速度,允许通过路径的小幅拉伸来大幅缩减节点的路由表,从而在路径长度和路由表规模之间获得比最短路径路由更好的平衡.针对通用网络或特定拓扑类型的网络提出了许多紧凑...     

Node-disjoint paths in incomplete WK-recursive networks

The incomplete WK-recursive networks have been recently proposed to relieve the restriction on the sizes of the WK-recursive networks. In this paper, a maximal set of node-disjoint paths is constructed between arbitrary two nodes of an incomplete WK-recursive network. The effectiveness of the constructed paths is verified by both theoretic analysis and extensive experiments. A tight upper bound on the maximal length is suggested. On the other hand, experimental results show that for arbitrary two nodes, the expected maximal length is not greater than twice their distance and about equal to the diameter. When the two nodes are the farthest pair, the maximal length is not greater than twice the diameter and the expected maximal length is not greater than 1.5 times the diameter.     

Broadcasting on Incomplete WK-Recursive Networks

The WK-recursive networks, which were originally proposed by Vecchia and Sanges, have suffered from a rigorous restriction on the number of nodes. Like other incomplete networks, the incomplete WK-recursive networks have been proposed to relieve this restriction. In this paper, broadcasting on the incomplete WK-recursive networks is discussed. The proposed broadcasting algorithm is optimal with respect to message complexity. Besides, extensive experiments are made to evaluate its performance. Experimental results show that (1) the heights of the broadcasting trees do not exceed the diameters, (2) a high percentage of the nodes can receive the message from the source node via the shortest paths, (3) for those nonshortest transmission paths, the deviations are small, and (4) a high percentage of the broadcasting trees are of minimum height.     

An Adaptive Routing Algorithm for WK-Recursive Topologies

This paper presents an easy and straightforward routing algorithm for WK-recursive topologies. The algorithm, based on adaptive routing, takes advantage of the geometric properties of such topologies. Once a source node S and destination node D have been determined for a message communication, they characterize, at some level l, two virtual nodes and that respectively contain S but not D and D but not S. Such virtual nodes characterize other (where is the node degree for a fixed topology) virtual nodes of the same level that contain neither S nor D. Consequently, it is possible to locate triangles whose vertices are these virtual nodes with property to share the same path, called the self-routing path, directly connecting to . When the self-routing path is unavailable to transmit a message from S to D because of deadlock, fault, and congestion conditions, the routing strategy can follow what we call the triangle rule to deliver it. The proposed communication scheme has the advantage that 1) it is the same for all three conditions; 2) each node of a WK-recursive network, to transmit messages, does not require any information about their presence or location. Furthermore, this routing algorithm is able to tolerate up to faulty links. Received: July 19, 1998; revised May 17, 1999     

Hamiltonicity of the WK-recursive network with and without faulty nodes

Recently, the WK-recursive network has received much attention due to its many favorable properties such as a high degree of scalability. By K(d,t), we denote the WK-recursive network of level t, each of whose basic modules is a d-node complete graph, where d>1 and t/spl ges/1. In this paper, we first show that K(d,t) is Hamiltonian-connected, where d/spl ges/4. A network is Hamiltonian-connected if it contains a Hamiltonian path between every two distinct nodes. In other words, a Hamiltonian-connected network can embed the longest linear array between any two distinct nodes with dilation, congestion, load, and expansion all equal to one. Then, we construct fault-free Hamiltonian cycles in K(d,t) with at most d-3 faulty nodes, where d/spl ges/4. Since the connectivity of K(d,t) is d-1, the result is optimal.     

一种基于最短路径介数的重要节点发现算法

网络中重要节点的发现是研究网络特性的重要方面之一,在复杂网络、系统科学、社会网分析和互联网搜索等领域中具有广泛的应用价值。为提高全网范围内重要节点发现的效率和有效性,提出了一种基于最短路径介数及节点中心接近度的重要节点发现算法,通过最短路径介数的方法确定全网内的重要节点,利用中心接近度分析重要节点的重要性。测试结果表明,与同类的系统比较起来,该方法具有比较好的性能。     

A regular scalable fault tolerant interconnection network for distributed processing

Bounded degree networks like deBruijn graphs or wrapped butterfly networks are very important from VLSI implementation point of view as well as for applications where the computing nodes in the interconnection networks can have only a fixed number of I/O ports. One basic drawback of these networks is that they cannot provide a desired level of fault tolerance because of the bounded degree of the nodes. On the other hand, networks like hypercube (where degree of a node grows with the size of a network) can provide the desired fault tolerance but the design of a node becomes problematic for large networks. In their attempt to combine the best of the both worlds, authors in [IEEE Transactions on Parallel and Distributed Systems 4(9) (1993) 962] proposed hyper-deBruijn (HD) networks that have many additional features of logarithmic diameter, partitionability, embedding, etc. But, HD networks are not regular, are not optimally fault tolerant and the optimal routing is relatively complex. Our purpose in the present paper is to extend the concepts used in the above-mentioned reference to propose a new family of scalable network graphs that retain all the good features of HD networks and at the same time are regular and maximally fault tolerant; the optimal point to point routing algorithm is significantly simpler than that of the HD networks. We have developed some new interesting results on wrapped butterfly networks in the process.     

网络容错路由算法概率分析的一种新的方法

该文提出了一种新的概率分析方法来研究在给定结点错误概率的情况下超立方体网络强容错路由算法的容错性的概率。针对文中提出的基于新的局部连通性网络容错模型的高效的强容错路由算法犤1犦,该文首次严格证明了一个具有1024个结点的10维超立方体网络能够容许多达4.7%的错误结点而具有99%的概率确保找到正确结点组成的路径,而如果结点的错误概率不超过0.1%,则所有实际规模的超立方体网络能够具有99.9%的概率确保找到正确结点组成的路径。该算法的时间性能是最优的,且该算法构造的路径的长度不超过源结点和目的结点之间海明距离的两倍加上一个很小的常数。     

A framework for end-to-end deterministic-delay service provisioning in multiservice packet networks

The problem of providing end-to-end delay guarantees for deterministic-delay services in multiservice packet networks is addressed through a combination of dynamic resource reservation and routing. Our model is based on using rate-controlled earliest-deadline-first (RC-EDF) for providing hard bounds on end-to-end delays. With RC-EDF, a certain delay bound has to be allocated for a connection at each node in the selected path. The most commonly used resource reservation policy is uniform allocation which is based on dividing the end-to-end delay bound equally among the nodes in the selected path. This simple allocation policy could lead to nonuniform resource loading and subsequently lead to high blocking rates. Moreover, the most commonly used routing method is shortest-path first routing which is known to lead to network hotspots. We propose a set of dynamic nonuniform resource reservation policies and dynamic routing methods. One of the routing methods is the well-known widest-shortest path method and the other is a dynamic routing method that adaptively adjusts link costs and uses a similar algorithm to shortest-path routing (e.g., Dijkstra's algorithm). We show that for both uniform and nonuniform traffic loading of some example network topologies that the combination of the proposed resource reservation policies and dynamic routing can lead to significant reduction in the connection blocking ratio in all loading conditions except for excessively high loads.     

Stability–throughput tradeoff and routing in multi-hop wireless ad hoc networks

We study the throughput of multi-hop routes and stability of forwarding queues in a wireless ad-hoc network with random access channel. We focus on a wireless network with static nodes, such as community wireless networks. Our main result is characterization of stability condition and the end-to-end throughput using the balance rate. We also investigate the impact of routing on end-to-end throughput and stability of intermediate nodes. We show that (i) as long as the intermediate queues in the network are stable, the end-to-end throughput of a connection does not depend on the load on the intermediate nodes, (ii) we show that if the weight of a link originating from a node is set to the number of neighbors of this node, then shortest-path routing maximizes the minimum probability of end-to-end packet delivery in a network of weighted fair queues. Numerical results are given and support the results of the analysis. Finally, we perform extensive simulation and verify that the analytical results closely match the results obtained from simulations.     

无线传感器网络一种不相交路径路由算法

无线传感器网络经常被用来采集物理数据,监测环境变化.由于低功耗无线通信不确定性、链路质量不稳定性以及节点失效等问题,传感器网络很容易导致路由数据包丢失.为了提高网络路由的可靠性,人们提出多路径路由算法.多路径路由中源节点到目的节点的多条路径可能含有公共节点,或者公共边,如果公共节点或者公共链路失效,则这个数据包也丢失,因此又有人提出不相交多路径路由算法.不相交多路径路由算法又分为链路不相交多路径路由算法和节点不相交多路径路由算法.提出了一种不相交路径路由算法,可以将感知节点采集到的数据通过不相交路径传送到汇聚节点,提高路由的可靠性.而且,这个算法还可以很方便地应用到多Sink节点的网络当中.该路由算法用到的路由表大小为|K|,其中|K|表示路径数.算法的运行时间复杂度是O(|L|),其中|L|表示网络中的边数.     

Topological Properties of WK-Recursive Networks

The WK-recursive networks, which have been proposed by Vecchia and Sanges, offer high degree of regularity, scalability, and symmetry. They have also the properties of expansibility and equal degree. Many algorithmic results have been obtained for the WK-recursive networks, and a VLSI implementation of a 16-node WK-recursive network has been realized. In this paper, we investigate some topological properties of the WK-recursive networks, including container, wide diameter, and fault diameter.     

Incremental design of scalable interconnection networks using basic building blocks

In this paper, we present an incremental design of scalable interconnection networks in multicomputer systems using basic building blocks. Both network topologies and routing algorithms are considered. We use wormhole-routed small-scale 2D meshes as basic building blocks. The minimum requirement to expand these networks is a single building block. This implies that the network does not have to maintain the regular 2D mesh topology. Some new topologies are introduced: incomplete meshes based on those adaptive routing algorithms designed from the turn model and extended incomplete meshes based on XY routing. We show that the original routing algorithm can be adopted to send a message between any source and destination without using store-and-forward and causing deadlock. The way that the network is constructed incrementally requires no or a very small amount of rewiring and keeps high bisection density and short diameter of the network. The design methods can be used to economically and incrementally build expandable and scalable parallel computers.     

An optimal fault-tolerant routing algorithm for weighted bidirectional double-loop networks

Double-loop networks are widely used in computer networks. In this paper, we present an optimal message routing algorithm and an optimal fault-tolerant message routing algorithm for weighted bidirectional double-loop networks. The algorithms presented are novel, and they do not use routing tables. After a precalculation of O(log N) steps to determine network parameters, the algorithms can route messages using constant time at each node along the route. The algorithm presented can route messages in the presence of up to three faulty nodes or links. The fault-tolerant routing algorithm guarantees an optimal route in the presence of one node failure.     

Designing networks with compact routing tables

Classes of network topologies are identified in which shortest-path information can be succinctly stored at the nodes, if they are assigned suitable names. The naming allows each edge at a node to be labeled with zero or more intervals of integers, representing all nodes reachable by a shortest path via that edge. Starting with the class of outerplanar networks, a natural hierarchy of networks is established, based on the number of intervals required. The outerplanar networks are shown to be precisely the networks requiring just one interval per edge. An optimal algorithm is given for determining the labels for edges in outerplanar networks.     

基于超节点的结构化P2P路由算法的研究

在对经典的结构化P2P路由算法研究的基础上,提出了BSNCCC(Based Super Node Cube Connect Cycle)路由算法。该算法节点维护的信息为O(1),查询步长为O(d)(节点个数N=d*2d),在充分考虑节点性能差异性的基础上,将性能好的节点作为路由过程中的主节点。模拟试验结果表明,在动态变化的P2P网络中,BSNCCC路由算法的效率优于Cycloid等算法。     

改进的无线传感器网络非均匀分簇路由算法

针对无线传感器网络中不均匀分簇引起能量空洞的问题,提出了改进的无线传感器网络非均匀分簇路由算法。该算法先根据节点剩余能量、节点到基站的距离、节点“度”和节点到簇头的距离等因素选举簇头;没有成为簇头的节点选择加入到距离最近的簇头所在的簇中,从而将整个网络划分为大小不等的簇;然后簇头再根据簇头剩余能量、簇头到基站的距离构造基于最小生成树的最优传输路径;通过簇内节点单跳、树内簇头多跳通信的方式将数据最终传输到基站。仿真结果表明,该路由算法能有效节约能量和均衡节点能耗,从而延长网络的生命周期。     

Efficient routing and sorting schemes for de Bruijn networks

We consider the problems of routing and sorting on a de Bruijn network. First, we show that any deterministic oblivious routing scheme for permutation routing on a d-ary de Bruijn network with N=dⁿ nodes, in the worst case, will take Ω(√N) steps under the single-port model. This improves the existing lower bounds provided d is not a constant. We also show that the lower bound is indeed a tight one. Second, we present a deterministic nonoblivious permutation routing algorithm which runs in O(d.n²) time on a d-ary de Bruijn network with N=dⁿ nodes. This algorithm is currently the fastest known nonoblivious deterministic routing algorithm for de Bruijn networks of arbitrary degree. Finally, we present an efficient general sorting algorithm for the de Bruijn networks of arbitrary degree. This algorithm is the best sorting algorithm known so far. It runs in O((log d).d.n²) time for directed de Bruijn network with dⁿ nodes, degree d, and diameter n. As a corollary, we show that on a binary de Bruijn network of Nnodes, our sorting scheme requires at most 2 log² Nsteps     

管道泄漏监测传感器网络的路由路径算法研究

分析管道流量泄漏监测的传感器网络特点,对传感器节点数据流量进行建模分析,如何保障在线监测网络设施的可用性,而链路通信质量随时空变化很大,并且有5%到15%的非对称链路存在。链路层服务不但可以发现邻居传感器节点,测量和预测邻居节点间的链路通信质量,而且还能提供链路数据转发机制减轻单向链路对其他协议的影响。为了提高路由路径的可靠性和减少能量损耗,利用链路层服务和分布式算法,为每个传感器节点建立到汇聚节点的最可靠路由路径,理论分析该算法的性能,在模拟器TOSSIM上进行仿真,实验结果表明基于链路层服务的最可靠路由路径建立算法,可充分利用单向链路建立更可靠的路由路径,有多于17%的节点建立更可靠的路由路径,路由路径的可靠性提高2%到51%。     

无线传感器网络异构驱动路由算法

融合表驱动路由和按需驱动路由的优点提出一种异构驱动的无线传感器网络路由算法,以实现无线传感器网络监测数据的高效汇集。算法将无线传感器网络的原有单一汇聚节点(Sink节点)扩充为一组无环连通点集,称为虚拟槽节点以覆盖全网。感知节点采用按需驱动路由策略将监测数据在短距离内传递给虚拟槽节点,随后数据在虚拟槽节点内部依照表驱动路由实现高速汇集。通过理论计算确定最优虚拟槽节点选取方式,并提出两跳邻居算法实现路由。经仿真实验,算法可保证网络内任意节点两跳可达虚拟槽节点,并通过分析仿真数据论证算法的有效性。