Summary of Capacity Estimation Tools Sample Clauses

Summary of Capacity Estimation Tools. ‌ CapProbe CapProbe is one of the most recent Capacity Estimation Tools. It sends a number of pairs and computes the capacity from the pair that has minimum delay sum: if d1i and d2i are the delays experienced by the two packets of pair i, CapProbe computes the capacity from the pair where d1i + d2i is minimum. The assumption here is that if a pair is affected by cross-traffic, then the delay of one of the two packets will increase, otherwise it will remain at a minimum value. Additionally, in order to avoid situations in which min d1 + d2 > min d1 + min d2 , CapProbe performs a sanity by checking that each of the two packets has experienced the minimum delay possible. This means that several PPs are sent and only the pair with the lowest delay is considered for the capacity estimate, as the others have probably been distorted by cross-traffic. Note that as the load increases and the network tends to saturation, the probability to have pairs free from cross-traffic tends to zero, i.e. the path is not measurable any more. Pathrate The pathrate methodology requires the cooperation of both the source and the sink, i.e., it is a two end-point methodology. Phase I: Packet pair probing: In this phase pathrate uses a large number of packet pair experiments. Using dispersion, each experiment gives an estimate of the capacity. The most frequent values, denoted modes, are returned. The goal is to uncover all the local modes of the bandwidth dis- tribution, expecting that one of them is the actual capacity. 2000 packet pair experiments using a packet size of L = 800 bytes are used in this pathneck, the authors seem to ignore the ADR despite the fact that the technique used is based on trains of packets. phase. The user has to specify the histogram bin width ω, which is also the resolution of the final capacity estimate. If, for example, the resolu- tion is ω=2 Mbps, pathrate will produce a final estimate that has a 2 Mbps accuracy. The sequence of local modes, in increasing order, is denoted