'QOS Enhancement with Partial State'

在设计网络内提供服务保障的机制方面已做了大量工作。这些方案大致可以分为两类，一类是需要为每个流维护状态的方案，另一类是不需要为网络中的每个流维护状态的方案。集成服务体系结构、差异化服务体系结构和差异化服务体系结构是此类方法的主要示例。这两种方法都有其优点和支持者。该建议旨在研究介于两个极端之间的方法，其中网络交换机可能能够为固定数量的流（可能少于它所服务的流的数量）保持状态。这个建议着眼于有限数量的州可以提供的服务。该提案计划追求研究提供具有有限状态的QOS的新方法的总体方向。我们最初的工作确定了以下指导原则：*所提供的服务需要是灵活的，也就是说，应该能够处理任何数量的状态（相对于流的数量）。*所提供的服务需要是可伸缩的，即增加状态的数量应该提高QOS。*所提供的服务需要是附加的，即随着更多的网络组件使用它，QOS应该得到改善。该提案计划调查能够提供以下QOS的机制：*识别和限制非响应流的资源消耗。*提供公平分享频宽。*为不同的流量提供带宽分配。作为第一步，我们建议在路由器上除了队列和缓冲区管理技术外，还采用采样和缓存技术来增强QoS。所建议的机制使用缓存来处理有限数量的状态，并使用采样来选择维护各个状态的流。我们的初步结果表明，采样和缓存可以有效地用于包含非响应流和公平共享带宽。该提案计划研究在当前定义的架构（如IntServ和DiffServ）中使用部分状态的有效性和可行性。该提案还计划研究部分状态是否可以用于提供延迟和抖动服务。除了研究机制外，该提案还计划对部分状态的有用性进行跟踪驱动和统计分析。可用的网络跟踪将用于研究状态对网络元素上要完成的工作量的影响，以及这种机制对QOS的影响。我们还计划用很好理解的网络流量模型来分析部分状态，看看我们是否可以对部分状态的影响做出定性的结论。

Considerable work has been done in devising mechanisms for providing service guarantees within a network. These schemes can be broadly classified into two categories, schemes that require maintaining state for each flow and schemes that do not require maintaining state for each flow withing the network. Integrated services architecture and differentiated services architecture and differentiated services architecture are prime examples of such approaches. Both the approaches have their advantages and proponents. This proposal aims to investigate approaches that fall in between two extremes, where a network switch may be able to maintain state for a fixed number of flows (possibly less than the number of flows it serves). This proposal looks at the services that can be provided by a limited amount of state. The proposal plans to pursue the general direction of investigating new approaches for providing QOS with a limited amount of state. Our initial work has identified the following guiding principles:*The provided service needs to be flexible i.e., should be able to work with any amount of state (relative to the number of flows). *The provided service needs to be scalable i.e., increased amount of state should improve QOS.*The provided service needs to be additive i.e., as more network components employ it, QOS should be improved.The proposal plans to investigate mechanisms that can provide the following QOS:*Identify and limit the resource consumptions of non-responsive flows.*Provide fair sharing of bandwidth.*Provide bandwidth allocations to different flows. As a first step, we propose to employ Sampling and Caching in addition to queue and buffer management techniques at a router to enhance the QoS. The proposed mechanism uses caching to deal with the limited amount of state and uses sampling to select flows for which individual state is maintained. Our preliminary results show that sampling and caching can be effectively used for containing non-responsive flows and fair sharing of bandwidth. The proposal plancs to study the effectiveness and feasibility of employing partial state in currently defined architectures such as IntServ and DiffServ. The proposal also plans to study if partial state can be used to provide delay and jitter service. Besides studying mechanisms, the proposal also plans to do both trace-driven and statistical analysis of usefulness of partial state. Available network traces will be used to study the impact of state on the amount of work to be done at a network element and the QOS impact of such mechanisms. We also plan to analyze partial state with well understood models of network traffic to see if we can make qualitative conclusions about the impact of partial state.