谈无路由器的园区网技术

本文首先了简述了Ｉｎｔｅｒｎｅｔ园区子网互联的一般方法，然后以以太网上ＵＮＩＸ主机互联问题为例，讨论了几种不使用物理路由器在园区网内互联ＩＰ子网的特殊技术，在本文末尾讨论的“快速虚路由法”为用户提供了一种简单，实用的Ｉｎｔｅｒｎｅｔ子网互联的选择方案。     

EPON系统中多播技术实现方案

首先分析了EPON下行各种通信模型的特点以及多播给系统带来的好处,然后提出了几种多播过滤方案,最后详细介绍了一套基于OAM帧的多播实现方案。     

Design and Analysis of an Efficient Communication Strategy for Hierarchical and Highly Changing Ad-hoc Mobile Networks

In this work we introduce two practical and interesting models of ad-hoc mobile networks: (a) hierarchical ad-hoc networks, comprised of dense subnetworks of mobile users interconnected by a very fast yet limited backbone infrastructure, (b) highly changing ad-hoc networks, where the deployment area changes in a highly dynamic way and is unknown to the protocol. In such networks, we study the problem of basic communication, i.e., sending messages from a sender node to a receiver node. For highly changing networks, we investigate an efficient communication protocol exploiting the coordinated motion of a small part of an ad-hoc mobile network (the runners support) to achieve fast communication. This protocol instead of using a fixed sized support for the whole duration of the protocol, employs a support of some initial (small) size which adapts (given some time which can be made fast enough) to the actual levels of traffic and the (unknown and possibly rapidly changing) network area, by changing its size in order to converge to an optimal size, thus satisfying certain Quality of Service criteria. Using random walks theory, we show that such an adaptive approach is, for this class of ad-hoc mobile networks, significantly more efficient than a simple non-adaptive implementation of the basic runners support idea, introduced in [9,10]. For hierarchical ad-hoc networks, we establish communication by using a runners support in each lower level of the hierarchy (i.e., in each dense subnetwork), while the fast backbone provides interconnections at the upper level (i.e., between the various subnetworks). We analyze the time efficiency of this hierarchical approach. This analysis indicates that the hierarchical implementation of the support approach significantly outperforms a simple implementation of it in hierarchical ad-hoc networks. Finally, we discuss a possible combination of the two approaches above (the hierarchical and the adaptive ones) that can be useful in ad-hoc networks that are both hierarchical and highly changing. Indeed, in such cases the hierarchical nature of these networks further supports the possibility of adaptation.     

Validating and Scaling the MicroGrid: A Scientific Instrument for Grid Dynamics

Large-scale Grids that aggregate and share resources over wide-area networks present major challenges in understanding dynamic application and resource behavior for performance, stability, and reliability. Accurate study of the dynamic behavior of applications, middleware, resources, and networks depends on coordinated and accurate modeling of all four of these elements simultaneously. We have designed and implemented a tool called the MicroGrid which enables accurate and comprehensive study of the dynamic interaction of applications, middleware, resource, and networks. The MicroGrid creates a virtual Grid environment – accurately modeling networks, resources, the information services (resource and network metadata) transparently. Thus, the MicroGrid enables users, Grid researchers, or Grid operators to study arbitrary collections of resources and networks. The MicroGrid includes the MaSSF online network simulator which provides packet-level accurate, but scalable network modeling. We present experimental results with applications which validate the implementation of the MicroGrid, showing that it not only runs real Grid applications and middleware, but that it accurately models both their and underlying resource and network behavior. We also study a range of techniques for scaling a critical part of the online network simulator to the simulation of large networks. These techniques employ a sophisticated graph partitioner, and a range of edge and node weighting schemes exploiting a range of static network and dynamic application information. The best of these, profile-driven placement, scales well to online simulation of large networks of 6,000 nodes using 24 simulation engine nodes.     

SSTT: Efficient local search for GSI global routing

In this paper, a novel global routing algorithm is presented for congestion opti-mization based on efficient local search, named SSTT (search space traversing technology). This method manages to traverse the whole search space. A hybrid optimization strategy is adopted,consisting of three optimization sub-strategies: stochastic optimization, deterministic optimiza-tion and local enumeration optimization, to dynamically reconstruct the problem structure. Thus,“transition” can be made from a local minimum point to reach other parts of the search space,traverse the whole search space, and obtain the global (approximate) optimal routing solution.Since any arbitrary initial routing solution can be used as the start point of the search, the initial-ization in SSTT algorithm is greatly simplified. SSTT algorithm has been tested on both MCNC benchmark circuits and industrial circuits, and the experimental results were compared with those of typical existing algorithms. The experimental results show that SSTT algorithm can obtain the global (approximate) optimal routing solution easily and quickly. Moreover, it can meet the needs of practical applications. The SSTT global routing algorithm gives a general-purpose routing solution.     

Say it Like You Mean it: Priming for Structure in Caller Responses to a Spoken Dialog System

In this paper we report results of a study undertaken to evaluate the initial prompts of open prompt style call-routing applications. Specifically, we examined how placement and phrasing of examples in the initial query affected caller responses and routing success. We looked at the comparative effectiveness of placing examples before and after the initial query and of phrasing these examples such that they promoted either a succinct structure in the form of a keyword or phrase, or a more complex but natural structure in the form of a question or statement. Findings indicate that examples encouraging a more natural structure, when presented prior to the initial query, result in significantly improved routing performance. We discuss this result in the context of using initial prompts to prime for desired structure in caller responses.     

Performance measures of an ant based decentralised routing scheme for circuit switching communication networks

 Swarm intelligence is a new challenging branch of artificial life which takes advantage of the collective behaviour of animals with limited intellectual faculties (insects, flocking birds, schools of fish) to solve algorithmically complex problems. Recently a new routing method based on the way that ants are communicating with each other has been applied to solve routing problems in telecommunication networks. This paper examines the behavior of an ant based decentralised router using an adequate set of commonly acceptable and some newly introduced metrics.     

基于IP组播的多媒体远程监控系统WebEye的设计与实现

随着Internet/Intranet网络技术与多媒体技术的发展,多媒体远程监控系统呈现出数字化、智能化等新特点。在此介绍了基于IP组播的多媒体远程监控系统WebEye的设计思想、系统构成以及部分实现技术。利用IP组播技术,监控的视音频、现场告警与控制信号可在不增加带宽的情形下传至网络所及的每一个感兴趣的监控节点,使得监控信息可以从监控中心释放出来。该系统具有良好的可扩展性和实用性。     

Mobility Management for Hierarchical Wireless Networks

In this paper, we consider the mobility management in large, hierarchically organized multihop wireless networks. The examples of such networks range from battlefield networks, emergency disaster relief and law enforcement etc. We present a novel network addressing architecture to accommodate mobility using a Home Agent concept akin to mobile IP. We distinguish between the physical routing hierarchy (dictated by geographical relationships between nodes) and logical hierarchy of subnets in which the members move as a group (e.g., company, brigade, battalion in the battlefield). The performance of the mobility management scheme is investigated through simulation.     

基于遗传算法求解全光网路由和波长分配问题

在Max-RWA模型的基础上提出了扩展的Max-RWA模型,引入了限定范围的波长转换器,并在简单考虑信号传输性能的基础上改进了优化目标,新的优化目标要求网络建立的连接数最大并使用尽可能少的波长转换器．数值结果和理论上界的对比表明文中遗传算法是稳定有效的．