CAREER: Quality of Service Engineering with Multiple Time-Scale Traffic

大量的实验研究已经证实了网络流量的多时间尺度和长程相关行为。特别是，幂律分布和类齐夫分布似乎是互联网固有的（文件大小，网络文档的流行程度，路由器的程度）。这些研究结果提出了以下问题：（i）是否可以开发有效的数学工具来建模和预测网络流量;（ii）如果适当调整，基于指数分布及其变体的经典QoS工程方法是否仍然有用。该项目旨在通过开发适用于当前和未来网络的易于处理的端到端QoS工程解决方案，为这些问题提供积极的，建设性的答案。 具体地说，本项目将致力于开发一种新的QoS方法，为多时间尺度业务量身定制，称为随机有界突发（SBB）演算。这种方法提供了强大的统计界限上的各种性能指标，如延迟，在网络的每个节点。SBB演算适用于非常一般的网络设置，并导致网络资源的高利用率。这个项目提出了解决一些基本的研究问题，对一个可能的实现SBB演算到实际的QoS架构，如，但不限于，DiffServ。这些问题涉及（i）流量特征和测量（ii）监管（iii）准入控制和QoS路由以及（iv）网络拓扑（SBB演算目前仅适用于非循环网络）。此外，这种方法的适用性，以新型的网络，如小型ad-hoc网络，将进行调查，在与诺基亚的合作努力。 接下来，本计画提出一个创新的架构，以建立模型并分析幂律分布，例如帕累托分布。所提出的框架是基于一个拟合过程，可以近似幂律分布任意密切的混合指数分布。这种建模方法为幂律分布的重要系统的设计和分析提供了新的视角。特别是，本项目提出利用这种方法，以分析和提高多服务器系统的性能，如Web服务器集群。 本计画的教育目标是发展一套丰富且具挑战性的电脑网路课程，并将服务品质工程建立为其中一个主要的学科。为此，计划建立一个新的互联网教学实验室，学生将有机会体验各种网络设备和通信技术。PI打算开发两个新的网络课程，一个本科生和一个研究生，将利用这一设施。此外，PI计划引入创新的教学方法，以提高学生的沟通技巧。

The multiple time-scale and long-range dependent behavior of network traffic have been established by numerous experimental studies. In particular, power-law and Zipf-like distributions appear to be inherent to the Internet (file size, popularity of web documents, degrees of routers). These findings are raising the questions of (i) whether effective and valid mathematical tools for modeling and predicting network traffic can be developed and (ii) whether classical QoS engineering methods, based on the exponential distribution and its variants, can still be useful, if appropriately adapted. This project aims at providing positive, constructive answers to these questions, through the development of tractable, end-to-end QoS engineering solutions, applicable to current and future networks. Specifcally, this project will focus on the development of a new QoS methodology, tailoredfor multiple time-scale traffic, termed Stochastically Bounded Burstiness (SBB) calculus. Thismethodology provides robust statistical bounds on various performance measures, such as delay, at each node of a network. The SBB calculus applies to very general network settings and leads to high utilization of network resources. This project proposes to address a number of fundamental research issues towards a possible implementation of the SBB calculus into practical QoS architectures, such as, but not limited to, DiffServ. These issues are related to (i) traffic characterization and measurements (ii) policing (iii) admission control and QoS routing and (iv) network topology (the SBB calculus currently applies only to acyclic networks). In addition, the applicability of this methodology to new types of networks, such as small ad-hoc networks, will be investigated, in a collaborative effort with Nokia. Next, this project proposes to elaborate an innovative framework for the modeling and theanalysis of power-law distributions, such as the Pareto distribution. The proposed framework isbased on a fitting procedure that can approximate a power-law distribution arbitrarily closely bya mixture of exponential distributions. This modeling approach provides novel perspectives on thedesign and analysis of important systems where power-law distributions arise. In particular, thisproject proposes to make use of this approach in order to analyze and improve the performance ofmulti-server systems, such as clusters of web servers. The educational goals of this project are to develop a rich and challenging curriculum in computer networking, and to establish QoS engineering as one of its major disciplines. For this purpose, a new Internet instruction laboratory is planned, where students will get the opportunity to experiment with various networking equipment and communication technologies. The PI intends to develop two new networking courses, one undergraduate and one graduate, that will take advantage of this facility. In addition, the PI plans to introduce innovative teaching methods in order to enhance the communication skills of the students.