End to End Modeling, Analysis and Parallel Simulation of Integrated Network Architectures

研究的重点是宽带综合业务数字网（B-ISDN）体系结构的端到端建模、分析和并行仿真。 ATM（异步传输模式）是B- ISDN体系结构的复用和交换技术. 端到端模型预测性能指标，如延迟和吞吐量，以设计一个准确的接纳控制协议的ATM网络是不能令人满意的。 它们要么在计算上太昂贵（因此不可能在真实的时间内在线执行），要么太简单和不准确。在没有令人望而却步的复杂性的情况下，精确度有相当大的改进余地。 而且，在大多数分析结果中，“质量服务”（QoS）的概念被淡化为仅仅是信元丢失概率。 因此，结果，例如，在呼叫接纳和呼叫管制中，主要通过它们关于信元丢失概率的有效性来判断。 采取额外措施（例如， 延迟和延迟抖动界限）将进一步限制可能的容许业务混合的集合，结果，经常使用的线性呼叫容许方法（以及相关的等效带宽定义）变得不充分。 因此，可能非常需要其他呼叫准入技术。 呼叫接纳算法的有效性可以调查，同时利用端到端模型的结果。 需要利用ATM网络所能提供的特殊控制特性，例如在中间节点中为连接分配缓冲器，或者在连接的寿命期间重新协商业务描述符或QoS。 本计画以Pade近似为基础，分析ATM网路端到端模型。此外，一个快速的并行仿真方法被用作一种补充技术。 注意，这些方法也可以用作 通用性能评估工具，并可应用于更大的建模问题集。

The research focuses on an important, so-far, unresolved issue of end-to-end modeling, analysis, and parallel simulation of Broadband Integrated Service Digital Network (B-ISDN) architectures. ATM (Asynchronous Transfer Mode) is the multiplexing and switching techniques for the B- ISDN architecture. The end-to-end models to predict performance measures such as delay and throughput in order to design an accurate admission control protocol for ATM networks are unsatisfactory. They are either computationally too expensive (And thus impossible to perform on-line in real- time) or too simplistic and inaccurate. There is considerable room for improvement in accuracy, without prohibitive complexity. Also the concept of `Quality Service` (QoS) has been trivialized in most analytical results to be just the cell loss probability. Consequently, results, e.g., in call admission and call policing, are primarily judged by their effectiveness concerning cell loss probability. The introduction of additional measures (e.g., delay and delay jitter bounds) will further restrict the set of possible admissible traffic mixtures, and as a result, the often-used linear call admission method (and the related equivalent bandwidth definition) becomes insufficient. Hence, other call admission techniques may very well be needed. The effectiveness of the call admission algorithms can be investigated while utilizing results from end-to-end models. There is a need to exploit the special control features that can be provided by an ATM network, such as the allocation of buffers to connections in intermediate nodes, or the re- negotiation of the traffic descriptor or of the QoS during the lifetime of a connection. In this project an analytical method based on Pade Approximation is used to analyze the end-to-end model for ATM networks. Also a fast parallel simulation approach is used as a complementary technique. Note that the methods can also be used as general purpose performance evaluation tools and can be applied to a larger set of modeling problems.