跨越不同容量设置DWDM网络的动态IP/DWDM综合路由算法研究

IP/DWDM网络的综合路由中的一个重要的研究问题就是如何对跨越不同DWDM网络的IP路由进行综合路由,特别是当两个DWDM网络的容量设置不同时。本文着重解决的就是如何对从单波长带宽大的网络进入单波长带宽小的网络传输的IP业务的综合路由问题。根据尽量鼓励对波长链路的带宽进行完全使用,以减小波长链路带宽碎片的原则,我们提出了两种解决算法:1 n 算法和 m n算法。仿真结果对两种算法的效率和性能进行了测试。     

基于遗传算法的WDM光传送网恢复优化算法

本文针对WDM光传送网的网络恢复问题,提出了一种基于遗传算法的恢复路由优化算法.在满足多重约束的条件下,该算法可处理不同故障情况下的多种最佳恢复路由的选取问题.通过对实际网络的计算,验证了该算法具有较强的实用性.     

Secure routing in mobile wireless ad hoc networks

We discuss several well known contemporary protocols aimed at securing routing in mobile wireless ad hoc networks. We analyze each of these protocols against requirements of ad hoc routing and in some cases identify fallibilities and make recommendations to overcome these problems so as to improve the overall efficacy of these protocols in securing ad hoc routing, without adding any significant computational or communication overhead.     

高速IP路由查找中改善更新性能的方法

现有的高速IP路由查找算法更多地强调路由表的查找,却忽视了路由表的更新。而路由表的更新对整个路由查找算法的性能和实际应用有不可忽视的影响。分段式查找树(Multibittrie)查找算法作为常用的IP路由查找算法,具有算法简单、有效等特点,但是更新速率较慢。作者提出一种在分段式查找树中控制路由表更新时间的方法,此方法能够较大地改善分段式查找树的更新性能。文章对更新性能的改善作了论述。     

基于GIS的河道、蓄滞洪区洪水演进动态可视化仿真研究

结合地理信息系统(GIS)技术和三维仿真图示技术,探讨了基于GIS的河道、蓄滞洪区洪水演进可视化仿真技术原理与方法,分析了洪水演进可视化模型的建立过程,设计出河道、蓄滞洪区洪水演进系统的总体结构及开发模式,并介绍了系统具体功能的实现.本仿真模型在实例中得到了成功的应用,可为防洪减灾决策提供快捷、直观形象的信息支持.     

Shortest expected delay routing for Erlang servers

The queueing problem with Poisson arrivals and two identical parallel Erlang servers is analyzed for the case of shortest expected delay routing. This problem may be represented as a random walk on the integer grid in the first quadrant of the plane. An important aspect of the random walk is that it is possible to make large jumps in the direction of the boundaries. This feature gives rise to complicated boundary behavior. Generating function approaches to analyze this type of random walk seem to be extremely complicated and have not been successful yet. The approach presented in this paper directly solves the equilibrium equations. It is shown that the equilibrium distribution of the random walk can be written as an infinite linear combination of products. This linear combination is constructed in a compensation procedure. The starting solutions for this procedure are found by solving the shortest expected delay problem with instantaneous jockeying. The results can be used for an efficient computation of performance criteria, such as the waiting time distribution and the moments of the waiting time and the queue lengths.     

内容发布订阅中支持订阅覆盖的事件丢失检测和恢复算法研究

基于内容的“发布／订阅”系统通过考虑订阅问的覆盖关系，使得某些订阅不需要转发给所有代理，从而可以减少中间代理的路由表大小，但是由于链路失效、拓扑重配置等原因，某些订阅者可能收不到事件消息，已有事件丢失检测算法都假设每个订阅必须转发给了所有代理，无法支持订阅覆盖的路由，本文提出了一种支持订阅覆盖的概率事件丢失检测和恢复算法，并通过模拟验证了该算法的有效性．     

Design of stochastic hitless‐prediction router by using the first exceed level theory

This paper deals with an enhanced hitless‐prediction router system that has the hitless‐restart capability with forecasting. Hitless‐restart means that the router can stay on the forwarding path and the network topology remains stable. But the major difficulty of the current hitless‐restart is that the router is always active to take the action, such as non‐stop forwarding (upgrade, maintenance and capacity expansion may be included as third party activities). Stochastic hitless‐prediction model gives the decision making factors that manage a router system more efficiently. An analogue of the first exceed level theory is applied for the restriction of the number of buffer size that is the router capacity. Analytically, tractable results are obtained by using a first exceed level process that enables us to determine the decision making factors such as recycle periods of the hitless‐prediction point to prevent a router shutdown. Copyright © 2005 John Wiley & Sons, Ltd.     

A greedy switch-box router

The greedy channel router of Rivest and Fiduccia is extended into an efficient switch-box router. The algorithm is based on two simple operations called join-split-nets and jog-to-right-target derived from the channel router. Terminals are on the boundary of a rectangular region, and the router uses two orthogonal layers of wires to generate the solution. The router always succeeds in finding a solution by inserting sufficient horizontal and vertical tracks in case of insufficient routing area. The result is generated through a single column-wise scan across the routing region. The expected running time is proportional to M(N + N_net), where M, N and N_net are respectively the number of columns, rows and nets in the region. The scan direction is crucial to the algorithm and we have proposed good heuristic which is based on the augmented channel density distribution in finding it. Results from a number of examples are evaluated. The implemented router is designed for assembling custom VLSI designs, it works in parallel with other tools such as a layout editor via a simple interface. The router output is in CIF.