Traffic Control for Networks with Aggregate Quality-of-Service

随着互联网不断扩展到新的应用领域，对提供不同程度的服务质量(Qos)的区分服务的需求也在不断增长。直到最近，互联网中的服务区分方法一直集中在为单独的业务流提供服务质量保证。这种按流量计算的模式尚未被广泛接受，这在很大程度上是因为需要在网络中维护大量状态信息。因此，网络社区目前正在重新定义互联网的服务质量的概念，从而产生了一种新的服务模型，其中对适当的流而不是对单个流进行保证。例如，由IETF中的区分服务(DiffServ)工作组定义的聚合服务质量的概念与传统的网络概念非常不同，并且需要用于流量控制和供应的新算法。这项研究的目的是深入了解业务聚合的服务质量的本质和交付方式，以下称为聚合服务质量。聚合服务质量服务模型的一个主要特征是不需要用户指定流量的组成或目的地。这极大地增加了网络资源配置的复杂性，并表明必须开发新的反馈密集型流量控制算法，以减轻网络负载的不确定性。目前，很少或根本没有理论来指导这类算法的发展。建议的研究将通过开发分析工具来纠正这种情况，使下一代互联网的聚合服务质量成为可能。该建议的三个主要研究部分涉及分析技术的开发和计算模拟实验1。该项目建议开发一种新的流动流网络优化模型，该模型将有助于(A)快速分析聚合的Qos网络和(B)基于关于网络流量模式的反馈来改进路由。使用一种新的所谓有效包络的构造，该项目将开发一种计算具有聚合服务质量的网络中的统计多路复用增益的方法。统计多路复用增益的知识对于确定网络中可以支持的具有聚合QOS的业务量是必不可少的。该项目将建立一个数据包级模拟环境，该环境将能够为聚合的Qos网络开发和测试各种流量控制算法。这项研究将有助于确定比较流量控制算法支持聚合服务质量的效果的指标。我们工作的一个重要部分是确定基于反馈的流量控制可以在多大程度上缓解供应问题。通过提供聚合服务质量的理论参考框架，为容量供应和准入控制提供工具和技术，拟议的研究将补充目前正在进行的互联网区分服务的标准化工作。

As the Internet continues to expand into new application domains, there is a growing demand for differentiated services that provide varying degrees of Quality of Service (QoS). Until recently, the approach for service differentiation in the Internet has focused on providing QoS guarantees to individual traffic flows. This per-flow model has not been widely embraced, largely due to the vast amount of state information that needs to be maintained in the network. As a consequence, the network community is currently redefining the notion of QoS for the Internet, leading to a new service model where guarantees are made to appropriate flows, rather than to individual flows.The notions of aggregate QoS which are being defined, e.g., by the Differentiated Services (DiffServ) working group in the IETF, are very different from traditional networking concepts and require novel algorithms for traffic control and provisioning. The objective of the proposed research is to give fundamental insights into the nature and delivery of QoS to traffic aggregates, henceforth called aggregate QoS.A central feature of service models for aggregate QoS is that there is no requirement for users to specify the composition or the destination of traffic. This significantly complicates the provisioning of network resources and suggests that new, feedback-intensive traffic control algorithms must be developed to mitigate uncertainty about network loading. At present there is little or no theory available to guide the development of such algorithms. The proposed research will remedy this situation by developing analytical tools that will make aggregate QoS possible for the next-generation Internet.The three main research components of this proposal involve development of analysis techniques and computational simulation experimentation.1. The projectl proposes to develop a novel fluid-flow, network-optimization model that will facilitate (a) rapid analysis of aggregate QoS networks and (b) improved routing, based on feedback about network traffic patterns.2. Using a new construct of so-called effective envelopes, the project will develop a method for computing the statistical multiplexing gain in a network with aggregate QoS. Knowledge of the statistical multiplexing gain is essential for determining the amount of traffic with aggregate QoS that can be supported in a network.3. The project will build a packet-level simulation environment, which will enable the development and testing of a wide variety of traffic control algorithms for aggregate QoS networks. This research will help to identify metrics for comparing the effect of traffic control algorithms to support aggregate QoS. An important part of our work is to determine the extent to which feedback-base traffic control can alleviate the provisioning problem.By providing a theoretical reference frame for aggregate QoS, which provides tools and techniques for capacity provisioning and admission control, the proposed research will complement the currently ongoing standardization efforts for differentiated services on the Internet.