孫雅麗2006-07-262018-06-292006-07-262018-06-292000http://ntur.lib.ntu.edu.tw//handle/246246/18814隨著網際網路的盛行，許多網路應用 程式相繼出現，這些應用需要得到一定程 度的傳輸服務品質保證，才能讓使用者感 受到其實用性，但目前的網際網路只提供 盡力服務，並不能給予這些應用程式有效 的支援。目前已經發展出一些即時媒體應 用能夠視封包遭遇到的延遲動態調整資 料的傳送，他們並不需要絕對可靠的封包 延遲上限，但必須盡可能避免封包在傳輸 過程中被丟棄，本研究即針對這類應用程 式提供『無壅塞服務』，我們將其定義為 『保證聚合資料流的最大封包遺失率為 ε』，希望將來可以應用於IETF 整合服務 架構下的負載控制服務。本研究首先對台 大校園骨幹網路做實際流量的量測及趨 勢分析，以瞭解網路資料流的特性。結果 顯示網路負載具有近似常態分配的特 性，可進一步用於網路流量的預測以及網 路資源的規劃與控制。此外，我們針對『無 壅塞服務』的提供，提出一個動態頻寬與 緩衝區分配的方法。實驗結果顯示避免頻 寬使用率太高及動態分配頻寬可以有效 抑制壅塞的發生。當網路流量的自我相似 性不是很顯著時，配置適量的緩衝區更有助於封包遺失率的降低。High quality, absolute guaranteed service may not be required by all applications. Many real-time applications, such as nv, ivs and vic, recently developed for packet-switched networks are capable of adapting their transmission to actual packet delays. They can as well tolerate occasional delay bound violations in the presence of transient network congestion. For this type of applications, an absolutely reliable bound on packet delivery times is not required. Moreover, many non-real-time applications such as on-line transaction processing and distributed simulation would desire a congestion-free packet delivery service from the network. This new type of service is called “Congestion-Free Service” with the guarantee of a maximum packet loss rate. This work considers resource allocation in the support of “Congestion-Free Service” in Broadband Internet. First, we studied traffic characterization under different measurement models via analyzing traffic traces collected from National Taiwan University campus network. The results show that traffic load can be approximated by the Normal distribution. In the second part of the work, we proposed a dynamic bandwidth and queue management scheme to support “Congestion-Free Service.” Simulation results show that in order to maintain a maximum packet loss rate, it is important that the system avoids operating at heavy loads, i.e. high link utilization. In a link sharing system, dynamic bandwidth allocation based on input loads can effectively avoid congestion. Furthermore, when combined with active queue management, it can further accommodate transient traffic bursts for non-self-similar traffic.application/pdf61148 bytesapplication/pdfzh-TW國立臺灣大學資訊管理學系暨研究所無壅塞封包遺失率流量量測量測窗頻寬分配緩衝區管理congestion-freepacket loss ratetraffic measurementmeasurement windowbandwidth allocationbuffer managementotherhttp://ntur.lib.ntu.edu.tw/bitstream/246246/18814/1/892219E002002.pdf