TR-IIS-05-004    Fulltext

Queuing Delay Propagation Model (QDPM)-based Queuing Region Determination for Available Bandwidth Estimation of Multimedia QoS

Yu-Chen Huang, Chun-Shien Lu, Hsiao-Kuang Wu


Available bandwidth is an important factor that can be used to adapt the sending rate to network conditions, so that packet loss, caused by congestion, can be significantly reduced before error control mechanisms are employed. To this end, we propose an active probing-based queuing delay propagation model (QDPM)-based scheme for available bandwidth estimation. Common assumptions, including use of the fluid traffic model and restriction to the single-hop network model, that have been made in the literature are relaxed in this study. Unlike the increasing trend of one-way delays that is widely used in probe rate model-based methods, in the proposed method, we exploit the magnitude relationship among the input gap, output gap, and queuing delay to define the types of queuing regions for each packet pair. In addition, we quantify the captured traffic ratio (CTR), which is defined as the total output gaps of joint queuing regions per total input gaps, and use it to derive the relationship between probing rate and available bandwidth. To justify the performance of our method, we further investigate how the estimation resolution and the probing noise ratio are related to the accuracy of available bandwidth estimation. Extensive simulations have been conducted and comparisons with other methods have been made to verify the effectiveness of our method for accurate and smooth estimation, no matter whether single-hop or multi-hop environments are considered.

keywords: Available bandwidth, Bottleneck, Congestion, Quality-of-Service (QoS), Queuing delay, Queuing region, TCP