SummaryThe benefits of the peer-to-peer paradigm have been proven through various applications besides file sharing. The requirements for the design of peer-to-peer overlay networks vary according to its purpose. In order to compare existing overlay networks and determine their suitability for specific purposes, requirements are defined with abstract quality attributes. Once the benchmarking set (quality attribute, metrics, and scenarios) is identified, experiments should be applied under the same circumstances on each overlay in order to obtain comparable results. This paper presents PeerfactSim.KOM, a simulator providing a benchmarking platform for peer-to-peer systems, especially for overlay networks. It supports defined benchmarking sets for all kinds of peer-to-peer overlays through an implemented catalogue of metrics and a simple but comprehensive scenario specification. Various peer distributions and churn rates are given which also supports geographical-location dependence. The platform is extensible due to its modular design and can scale up to around 10