CAREER: Performance Evaluation of Gigabit Ethernet Networks, A Systems and Experimental Approach

很明显，ATM和以太网都将构成“未来的网络”。以太网正在从半双工CSMA/CD快速过渡到全双工交换操作。虽然目前ATM网络的许多研究都与这两种类型的网络有关，但在以太网领域仍然存在许多亟待解决的问题。这些问题包括：1。未来千兆应用的流量特性还没有被预测出来。目前的流量模型可能不适用于千兆应用。因此，需要更好地了解来自预期千兆应用程序的流量，以便能够预测网络性能。2. 对于高速网络，内存速度限制输出缓冲和共享内存交换机架构到低端口密度。由于这个原因，调度算法实现高吞吐量的输入缓冲仅ATM交换机已成为最近的研究课题。然而，目前还没有在输入缓冲交换机和全双工中继器中容纳可变长度数据包和服务质量（QoS）的调度算法或交换机体系结构。3. 虽然交换操作可能在未来的网络中占主导地位，但千兆半双工CSMA/CD以太网的低效率仍然存在，需要解决。这个为期四年的职业生涯项目的目标就是解决这些问题。现有的交通模型很大程度上是基于交通轨迹的时间序列分析，导致对观察到的交通特征的原因的理解有限。通过测量应用程序和协议实现来研究预期的千兆应用程序的用户行为、源数据对象以及应用程序和协议行为，将获得新的知识。将所得到的流量模型作为将要开发的性能模型的输入，用于高度可扩展的、只提供输入缓冲的交换机的方法将得到改进，从而为突发的、尽力而为的数据流量和保证服务流量流提供高吞吐量和高效支持。假设通过在每个输入端口使用流量整形，可以使调度算法变得简单和可扩展。本文将研究分组爆破与间隔、优先级排队和选择性PAUSE流控制的适用性。为了在具有高数据速率的大跨度半双工千兆以太网上支持CSMA/CD，必须有效地将当前最小64字节的数据包大小增加到512字节，以允许正确的碰撞检测。IEEE 802.3千兆以太网标准使用分组爆破来传输小数据包。将研究一种更有效和可互操作的操作方法，允许后期碰撞，可以检测并正确处理。将采用系统和实验的方法来解决这些问题。将建立一个千兆以太网连接个人电脑和服务器的实验室。该实验室将用于直接实验，作为并行执行模拟模型的设施，并用于研究生和本科生的相关教育活动。将开发一种用于并行独立复制模拟模型的工具，并使之普遍可用。更重要的是，流量建模的新思想，支持QoS的可变长度数据包的交换机调度的新知识，以及在大跨度半双工以太网中使用CSMA/CD的新方法将在适当的会议和期刊上以及向标准机构提出。为了征求输入并产生外部参与，将建立一个带有公告板的WWW网站，供学术界和工业界的研究人员和开发人员分享软件工具、新想法和发现。此外，还将举办一个讲习班。因此，新的想法将被播种到研究界。教育计划南佛罗里达大学工程学院目前有一个新的信息系统本科学位。信息系统的研究生课程正在考虑中。该职业计划将为信息系统学位课程提供强大的网络和性能建模重点。将开发新的课程和课程，并将研究成果带入课堂。重点将放在实验和实践项目上，学生将在团队中工作，利用前沿知识解决现实世界中的问题。作为这个项目的结果而开发的教育材料将被用作对ACM和IEEE-CS正在进行的开发信息系统课程指南的贡献。为了鼓励本科生攻读工程专业的研究生教育，本职业计划的部分内容已明确确定为本科生的研究参与。

It is evident that both ATM and Ethernet networks will comprise the "network of the future". Ethernetnetworks are rapidly transitioning from half-duplex CSMA/CD to full-duplex switched operation. While much of the current research in ATM networks is relevant to both types of networks, there are significant remaining problems in the area of Ethernet networks that urgently need to be addressed. These problems include: 1. The traffic characteristics of future gigabit applications have not yet been predicted. Current trafficmodels may not be applicable for gigabit applications. Therefore, better knowledge of traffic fromexpected gigabit applications is needed to be able to predict network performance. 2. For high-speed networks, memory speed limits output buffered and shared memory switch architectures to low port densities. For this reason, scheduling algorithms which achieve high throughputs for input buffered only ATM switches have been the subject of recent research. Yet, there do not exist scheduling algorithms or switch architectures which accommodate variable length packets and Quality of Service (QoS) in input buffered only switches and full-duplex repeaters. 3. While switched operation will likely be predominant in future networks, inefficiencies in gigabit half-duplex CSMA/CD Ethernet still remain and need to be addressed. The objective of this four year CAREER program is to address these problems. Existing traffic models arelargely based on time series analysis of traffic traces resulting in a limited understanding of the causes of observed traffic characteristics. New knowledge will be gained by instrumenting application and protocol implementations to study the user behavior, source data objects, and application and protocol behaviors of expected gigabit applications. Using the resulting traffic models as input to performance models that will be developed, methods for highly scalable, input buffered only switches to provide high throughput and efficient support for bursty, best-effort data traffic and guaranteed-service traffic streams will be advanced. The hypothesis is that by using traffic shaping at each input port, the scheduling algorithm can be made simple and scalable. The applicability of packet bursting and spacing, priority queueing, and selective PAUSE flow control will be studied. To support CSMA/CD on large span, half-duplex Gigabit Ethernet networks with high-data rates, the current minimum 64-byte packet size must effectively be increased to 512 bytes to allow for correct collision detection. The IEEE 802.3 Gigabit Ethernet standard uses packet bursting to transmit small packets. A more efficient and interoperable method of operation whereby late collisions are permitted, can be detected, and handled correctly will be studied. A systems and experimental approach will be used to tackle the problems. A laboratory of Gigabit Ethernetattached personal computers and servers will be built. This laboratory will be used for direct perimentation, as a facility for parallel execution of simulation models, and for related educational activities at both the graduate and undergraduate levels. A tool for parallel independent replications of simulation models will be developed and made generally available. Much more significantly, new ideas in traffic modeling, new knowledge in switch scheduling for variable length packets with support for QoS, and new methods for using CSMA/CD in large span, half-duplex Ethernet networks will be presented in appropriate conferences and journals, and to standards bodies. To solicit input and generate external participation, a WWW site with a bulletin board will be established for researchers and developers from academia and industry to share software tools, new ideas, and findings. In addition, a workshop will be held. New ideas will thus be seeded into the research community. Education PlanThe College of Engineering at the University of South Florida currently has a new undergraduate degree trackin Information Systems . A graduate track in Information Systems is under consideration. This CAREER program will advance a strong networking and performance modeling focus for this Information Systems degree track. New courses and curricula will be developed and research results will be brought into the classroom. The emphasis will be on experimental and hands-on projects where students will work in teams to solve real world problems using cutting-edge knowledge. The educational materials developed as a result of this project will be used as a contribution to ongoing ACM and IEEE-CS efforts to develop curriculum guidelines for Information Systems programs. To encourage undergraduate students to pursue graduate education in engineering, portions of this CAREER program have been explicitly identified for undergraduate student research involvement.