In this paper we present impacts of the Ethernet capture effect on bandwidth measurements. We show that the unfairness caused by the Ethernet capture effect can have a severe impact on the ability to estimate available bandwidth. We define two metrics, surplus bandwidth and fair share bandwidth, that are protocol and application independent available bandwidth metrics. We propose a measurement method, the TOPP method, that measures link load with low risk of triggering an Ethernet capture effect. From TOPP measurements, we can estimate available bandwidth.