Slotted Optical Burst Switching (SOBS) networks

In the paper, we study Optical Burst Switching (OBS) networks. Since OBS still suffers high loss ratio due to the lack of buffer at the OBS core routers, we study methods to reduce the loss without using optical buffers. We consider time-slotted OBS called Slotted OBS (SOBS), where routers are synchronized and only send fixed length bursts at the beginning of time slots. Our simulation results show that SOBS reduces the packet loss probability significantly. Moreover, we show that SOBS can be implemented with little or no additional cost and has other advantages such as providing better support for Quality of Service (QoS).     

交换式以太网的计算机建模与仿真

文章在对以太网原理和运行机制以及交换式以太网工作原理深入研究的基础上,对交换式以太网系统进行了基于传输层的模型抽象,采用面向事件的模拟仿真建模方法定义网络实体以及相关事件,并且将仿真结果与实测数据进行了对比。     

以太网集群并行图像处理技术

基于以太网集群的并行图像处理系统具有价格低廉、性能较高、可扩展性好、应用前景广阔的优点,实用价值十分重要。针对同构以太网集群图像处理系统建立模型,并给出了在该模型下实现静态负载均衡的最短时间划分条件,最后的实验结果证明,文中的分析与实际运行情况十分吻合。     

一种基于流量映射代理的以太网流量均衡实现结构

流量均衡是提高网络性能的重要技术。随着基于以太网技术构建的网络规模不断扩大,如何实现流量均衡成为制约以太网技术发展的重要问题之一。针对该问题,论文提出了一种以太网流量均衡实现结构,该结构的核心部分是采用流量均衡选路算法的流量映射代理,它能够利用虚拟局域网技术和多生成树协议控制用户流量在网络中的分布,实现流量均衡。     

基于VLAN的以太网流量均衡选路算法

确定了衡量以太网中流量均衡效果的代价函数，在此基础上提出了一种基于虚拟局域网(VLAN)和多生成树协议(MSTP)的以太网流量均衡选路算法。通过仿真证明了该算法的有效性，并说明该算法可以适应不同的网络环境。     

Q-in-Q VLAN技术在城域以太网组网中的应用

随着以太网的应用逐渐从LAN扩展到MAN中,802．1Q逐渐表现出了组网上的不适应性。针对802·1Q在城域网组网中的不足,着重讨论了VLAN的扩展技术Qin-Q VLAN。本文从Q- in-Q的基本定义开始,讨论了不同用户数据业务承载的实现、Q-i矿Q实现城域以太网中的服务区分、用Q-in-Q组建城域网,以及在Q-in-Q的条件下以太网数据帧的处理过程。。最后,文章就Q-in-Q组网还需解决的其它问题作了简单的介绍。     

基于千兆以太网的数字视频监控系统在地铁中的应用

本文主要介绍了实现地铁视频监控的几种方式，比较了相应的几种图像压缩和传输的优缺点，提出了适合于地铁应用的以千兆以太网作为传输途径的数字视频监控系统设计方案。     

An optimization framework for the energy management of carrier ethernet networks with Multiple Spanning Trees

We propose an energy management framework to optimize the energy consumption of networks using the Multiple Spanning Tree Protocol such as Carrier Grade Ethernet networks. The objective is to minimize the energy consumption of nodes and links while considering QoS constraints. The energy management is done through the Multiple Spanning Tree Protocol (MSTP) by choosing from a given set the most appropriate Spanning Trees and the most appropriate edges to operate while respecting the traffic demands. A trade-off framework between energy consumption and network performance is proposed. Results show that it is possible to achieve a good traffic engineering while operating the network closer to the minimum energy value.     

MPLS网络流量工程的关键机制剖析

1 引言随着Internet的蓬勃发展,网络中新技术、新业务层出不穷,Internet已从单一的数据传送网逐步演化成为综合业务网。网络业务的多元化导致了对网络需求的复杂化,要求网络提供高效、可靠的服务,能够保证服务质量,这对网络流量工程技术提出了极大的挑战,人们迫切需要一种有效且切实可行的解决方案。 MPLS在无连接的网络中提供了面向连接的特性,使MPLS在实施流量工程方面有明显的优势。目前,大多数的流量工程解决方案都采用MPLS作为转发机制。许多研究人员     

以太网流量工程研究

该文在以往流量工程研究的基础上,通过对以太网技术发展和应用的现状分析,提出了以太网流量工程的定义,并对主要的以太网流量工程技术进行了系统的分析和概括,阐述了以太网流量工程的体系结构和基本方法。     

基于Ethernet的内存保护策略研究

根据嵌入式系统对内存分配可靠性要求,在研究现行PC机上通用的内存保护策略基础上,以开放源代码的嵌入式操作系统Ethernet内存管理为依托,提出了一种可行的内存保护策略。该策略可结合具体硬件的配置信息,选择相应的保护方法——上下边界标志法、锁——钥保护法和界限寄存器保护法,从而提高了嵌入式系统内存使用的可靠性。     

ATM网络拥塞预防的动态负载平衡策略

讨论了拥塞预防在ＡＴＭ网络中的必要性以及拥塞预防的关键性要素,并利用公式系统中并行计算的动态负载平衡的思想,提出了ＡＴＭ网络中负载的概念,给出了ＡＴＭ网络拥塞预防的算法。     

工业以太网实时通信中的调度表构建策略研究

介绍了一种工业以太网实时通信机制．在传输层和数据链路层增加了实时通信实体，在不改变以太网通信机制的前提下，通过调度信息的发送解决了以太网的通信冲突问题．工业以太网的实时通信调度需要与功能块调度协调一致；在对功能块调度机制进行分析的基础上，将功能块调度与实时通信调度相结合，提出了工业以太网实时通信中周期性时间调度表和非周期通信调度表的构建方法．     

Practical load balancing for content requests in peer-to-peer networks

This paper studies the problem of balancing the demand for content in a peer-to-peer network across heterogeneous peer nodes that hold replicas of the content. Previous decentralized load balancing techniques in distributed systems base their decisions on periodic updates containing information about load or available capacity observed at the serving entities. We show that these techniques do not work well in the peer-to-peer context; either they do not address peer node heterogeneity, or they suffer from significant load oscillations which result in unutilized capacity. We propose a new decentralized algorithm, Max-Cap, based on the maximum inherent capacities of the replica nodes. We show that unlike previous algorithms, it is not tied to the timeliness or frequency of updates, and consequently requires significantly less update overhead. Yet, Max-Cap can handle the heterogeneity of a peer-to-peer environment without suffering from load oscillations. Mema Roussopoulos is an Assistant Professor of Computer Science on the Gordon McKay Endowment at Harvard University. Before joining Harvard, she was a Postdoctoral Fellow in the Computer Science Department at Stanford University. She received her PhD and Master’s degrees in Computer Science from Stanford, and her Bachelor’s degree in Computer Science from the University of Maryland at College Park. Her interests are in the areas of distributed systems, networking, and mobile and wireless computing. Mary Baker is a Senior Research Scientist at HP Labs. Her research interests include distributed systems, networks, mobile systems, security, and digital preservation. Before joining HP Labs she was on the faculty of the computer science department at Stanford University where she ran the MosquitoNet project. She received her PhD from the University of California at Berkeley.     

The load balancing problem in OTIS-Hypercube interconnection networks

An interconnection network architecture that promises to be an interesting option for future-generation parallel processing systems is the OTIS (Optical Transpose Interconnection System) optoelectronic architecture. Therefore, all performance improvement aspects of such a promising architecture need to be investigated; one of which is load balancing technique. This paper focuses on devising an efficient algorithm for load balancing on the promising OTIS-Hypercube interconnection networks. The proposed algorithm is called Clusters Dimension Exchange Method (CDEM). The analytical model and the experimental evaluation proved the excellence of OTIS-Hypercube compared to Hypercube in terms of various parameters, including execution time, load balancing accuracy, number of communication steps, and speed.

A new step toward load balancing based on competency rank and transitional phases in Grid networks

Grid computing is a network of software-hardware capabilities. It serves as a comprehensive and complete system for organizations by which the maximum utilization from resources is achieved. Resource distribution in a heterogeneous and unstable environment and also effective load distribution among these resources are the important and difficult problems in Grid networks. Using dynamic and static algorithms or searching tree and Branch and Bound algorithm are considered to be among the available methods to reach the load balancing in Grid networks. This paper presents a new method for dynamic load balancing. In this method, we use the subtraction of forward and backward ants as a competency rank to take the priority of the sites, and we use a control word to search the suitable resource as well. Our main purpose is to devote jobs to the existing resources based on their processing power. Simulation results show that the proposed method can reduce the total completion time and also total tardiness to get the load balancing. The cost of using resources as an effective factor in load balancing is also observed.     

以太网络并行科学计算中通信损耗的定量描述

大型科学计算中常采用并行算法［１,２］,负载平衡是并行计算中的一个很重要的方面 １３,４１。在平衡负载的过程中需要用到通信损耗来描述网络并行计算的速度。该文探讨分析了影响通信损耗的各种因素,提出了一种新的以太网环境中的通信损耗的定量描述方法;阐述了并行科学计算在进行中通信损耗的实际获得过程。实验结果表明,该通信损耗的表示形式在实际应用中是正确可靠的。     

Hash-based proximity clustering for efficient load balancing in heterogeneous DHT networks

Distributed hash table (DHT) networks based on consistent hashing functions have an inherent load uneven distribution problem. The objective of DHT load balancing is to balance the workload of the network nodes in proportion to their capacity so as to eliminate traffic bottleneck. It is challenging because of the dynamism, proximity and heterogeneity natures of DHT networks and time-varying load characteristics.     

Enforcing the timing behavior of real-time stations in legacy bus-based industrial Ethernet networks

This paper proposes a virtual token-passing mechanism, which allows the coexistence of legacy industrial Ethernet devices with enhanced (real-time) devices in the same bus network. The VTPE mechanism allows the implementation of real-time (RT) applications upon legacy bus-based industrial networks, enforcing the adequate timing behavior of the supported applications. It enables the traffic separation between legacy Ethernet stations and enhanced (RT) stations. A set of experiments has been performed, which allowed to measure the message access delay and the token rotation time. The achieved results clearly demonstrate that the VTPE architecture enables the support of RT communication upon legacy bus-based industrial Ethernet networks, even when the communication medium is shared with uncontrolled traffic sources.     

Provision of differentiated performance in Optical Burst Switching networks based on burst assembly processes

Optical Burst Switching (OBS) has been designed as a practical solution for the high-speed transport network using enabling optical technologies, which can work without optical buffering or pure optical signal processing in the intermediate nodes. As a collection of many packets, optical bursts exhibit different traffic characteristics in the bufferless optical core networks compared to the packet-level traffic in the conventional electronic switching systems. However, many OBS studies often neglect this issue by assuming the inputs to be optical bursts when analyzing the system performance. This paper demonstrates that the loss performance of optical bursts is dramatically different when considering burst assembly process at the edge nodes and the connectivity of the core nodes. We develop some analytical models which can model the loss performance more accurately than the traditional methods. Based on our observations, we propose a scheme to support differentiated loss performances for optical bursts by modifying the burst assembly parameters at the source edge nodes. Our scheme is implemented at the edge nodes and there is no specific requirement to the core nodes. Thus, our design provides good flexibility and scalability in the heterogeneous Internet.