eChirp: Measuring available bandwidth for the Internet using multiple chirp packet trains.

摘要

Measuring available bandwidth over a network path in the Internet is a challenging research problem. In this thesis we have studied this problem and developed a new technique called "eChirp". First, the effectiveness of pathChirp [1] is studied in terms of model performance of chirp packet train structure, actual bandwidth, queuing delay and excursion segmentation. Then we remodeled the chirp train structure. The eChirp can measure the available bandwidth over a network path efficiently and accurately with heavy and light load links. To measure the available bandwidth, the packet probing rate configuration used in pathChirp technique is modified by changing its chirp train structure. The modified structure uses multiple chirp trains (three trains) that provides better probing rate configuration and ultimately gives better bandwidth measurement. Per-packet available bandwidth is calculated using weighted average of per-packet bandwidth of three trains. We also determined the bounds of probing rate parameter which was questionable in pathChirp and affects the available bandwidth measurement accuracy. The eChirp technique has been experimented with numerous network path topologies with low and high link loads with CBR cross-traffic conditions using NS-2 simulated network and results are compared with most recent pathChirp technique. Simulation results show that the proposed eChirp technique is better than pathChirp scheme in terms of estimating available bandwidth.