IMR-Pathload: Robust Available Bandwidth Estimation Under End-Host Interrupt Delay

Many paths in PlanetLab cannot be measured by Pathload. One of the main reasons for this is timing irregularities caused by interrupt moderation of network hardware, which delays generation of interrupts for a certain period of time to reduce per-packet CPU overhead. Motivated by this problem, we study Pathload in detail under various end-host interrupt delays and find that its trend detection mechanism becomes susceptible to non-negligible interrupt delays, making it unable to measure network paths under such conditions. To overcome this, we propose a new method called IMR-Pathload (Interrupt Moderation Resilient Pathload), which incorporates robust trend detection algorithms based on signal de-noising techniques and reliably estimates available bandwidth of network paths under a wide range of interrupt delays. Through experiments in Emulab and Internet, we find that IMR-Pathload substantially improves Pathload’s measurement reliability and produces accurate bandwidth estimates under a variety of real-life conditions.