Locating the tightest link of a network path

The tightest link of a network path is the link where the end-to-end available bandwidth is limited. We propose a new probe technique, called Dual Rate Periodic Streams (DRPS), for finding the location of the tightest link. A DRPS probe is a periodic stream with two rates. Initially, it goes through the path at a comparatively high rate. When arrived at a particular link, the probe shifts its rate to a lower level and keeps the rate. If proper rates are set to the probe, we can control whether the probe is congested or not by adjusting the shift time. When the point of rate shift is in front of the tightest link, the probe can go through the path without congestion, otherwise congestion occurs. Thus, we can find the location of the tightest link by congestion detection at the receiver.