中文摘要：

可用带宽与紧链路是两个重要的QoS指标，在拥塞控制、流媒体应用、QoS验证、服务器选择等领域具有重要意义。文章详细描述了Pathtrait，一种可以准确测量可用带宽和定位紧链路的方法。Pathtrait基于一种全新的探针结构，以捕获探针队列在路径某跳的输入速率和输出速率，由此定位紧链路、估算紧链路处的链路可用带宽。该文在NS2仿真环境中验证了Pathtrait的准确性。

英文摘要：

Available bandwidth and tight link are two important QoS metrics and plays a fundamental role in congestion control,streaming applications,QoS verification and server selection.In this paper,we fully describe Pathtrait,a methdology which is based on an original probing structure to capture the input rate and output rate of a single probing train at certain link among the estimated network path,through which to infer the tight link and estimate the available bandwidth of the tight link.Pathtrait is validated in NS2 simulation,which proves pathtrait to be accurate.