臺灣博碩士論文加值系統

　　在非同步傳輸模式的綱路上必須支援具有不同服務品質保證的服務，所以需要封包排程的方法，以增加綱路資源的使用效率並且保證服務品質的要求。先來先服務的方法是最簡單且最容易用硬體實做的。但是因為它缺少優先權的處理和緩衝區使用效率不好，所以它不適合支援服務品質保證的服務。在這篇論文中，我們提出一個修改先來先服務並且保證服務品質的方法。它繼承先來先服務簡單的特性，而且使用有適應性的緩衝區以保證封包遺失率的要求。因此我們的方法具有簡單的特性，並且能處理不同優先權的服務。在效能評估上，我們的方法的確比以往的研究佳。

　　Multiple services with heterogeneous Quality Of Services (QoS) requirements are supported in ATM networks. The cell scheduling discipline is needed to utilize the network resources efficiently and guarantee the QoS requirements. FCFS is the simplest and easiest scheme for hardware implemeyntation. However, because of its lack of support of prioritizing scheme and inefficiency of buffer usage, it is not suitable to support QoS -guarantee servics .Therefore, a modified FCFS scheme with QoSguarantee is proposed in this paper. Inheriting the simplicity of FCFS, we modify the FIFO by adding adaptive queues for priority handing to satisfy the diverse QoS requirements. The buffer sizes of the adaptive queues could be decided by the traffic load and cell delay constraint to grarantee the cell loss rate. As a result, the proposed modified FIFO scheme is simple in hardware implementation, while it has the ability to handle multiple QoS priorities. The performance evaluation shows that the accessible offered load in our proposed scheme is better than the others proposed before.