A scheme for measuring subpath available bandwidth

This paper presents a novel probing scheme which can be used for estimating the available bandwidth of subpaths, without the requirement of control over both endpoints of a network path. Instead of a probe-packet receiver, this scheme uses the ICMP capability of routers. An estimate of the available bandwidth from the endpoint to a router is obtained in much the same way as for state-of-the-art end-to-end probing methods. Taking into account ICMP packet generation limitations and delay, the estimate should be interpreted as a lower bound of the actual available bandwidth. By combining estimates for several routers along a path, it is possible to obtain lower bound estimates also for subpaths between routers. These bounds may be further sharpened if combined with an estimate from an end-to-end measurement. From the obtained subpath bounds, it may be possible to identify a portion of the end-to-end path containing the bottleneck link. It is also possible to infer lower bounds for the individual router hops. In order to demonstrate the feasibility of this ICMP-based scheme, the paper reports on a measurement study conducted over the Internet.