一种基于应用需求的网络路径可用带宽测量策略

报文对间隔及报文单向延迟的变化可以反映报文发送速率与可用带宽的大小关系,根据这个规律本文提出了一种基于应用需求的网络路径可用带宽测量策略COPP.COPP发送多组发送速率不断增大的报文对序列,并从每组序列中求出所有成为转换点的报文对,然后根据这些报文对所受干扰的不同程度赋以它们不同的权重,从而得到路径可用带宽.COPP可根据具体应用不同的带宽需求动态决定测量范围,仿真实验研究了测量中探测报文大小的选择,并通过与Pathload等其它带宽测量方法的比较验证了COPP具有低开销、高精度、平稳性好且对网络状态变化敏感等优点.

Towards Estimating Available Bandwidth on Network Paths with Application Requirements

This paper proposes COPP, i. e. chirp of packet pairs, a novel active method to yield available bandwidth along network paths. The probes in COPP are composed of several chirps of packet pairs,e, g. several trains of packet pairs where the interval between the first and the second packet within packet pair is gradually decreased. For each chirp of packet pairs traversed the measured path, we find out all turning points in the chirp, and then give them distinct weight in the final available bandwidth calculation according to the degree of experienced distortion. The turning point is such a packet pair that is disturbed more obviously by cross traffic in contrast to its neighbor pairs. Two rules are developed to detemine whether a packet pair is a turning point or not. Additionally, COPP can determine its estimate bound dynamically by exploiting the bandwidth requirements of concrete applications if known. We also inspect the selection of the probe packet size in COPP through simulations. Finally, comparisons between COPP and other measurement tools such as Pathload and Spruce show that COPP is an agile and stable technique and can provide relatively higher accurate results with fewer overheads.