iPerf Network Bandwidth Tool

iPerf is a widely used open-source tool for active network bandwidth measurements, allowing users to measure maximum achievable TCP and UDP throughput between two endpoints. Originally developed by the National Laboratory for Applied Network Research (NLANR) and currently maintained as iPerf3 by ESnet at Lawrence Berkeley National Laboratory, iPerf has become the standard tool for network performance testing worldwide. Key features: TCP and UDP testing (measure TCP throughput with configurable window sizes, MSS, and congestion control algorithms including BBR, Cubic, and Reno, plus UDP testing with configurable bandwidth, packet size, and jitter measurement). Client-server model (run iperf3 server on one end and client on the other, with the server accepting multiple connections and the client initiating tests with configurable duration, interval, and parallel streams). Bidirectional testing (reverse mode for testing download direction, bidirectional mode for simultaneous upload and download measurement). JSON output (structured JSON output for integration with monitoring scripts and dashboards). Multiple streams (parallel data streams for saturating high-bandwidth links, configurable with the -P flag). IPv4 and IPv6 (full support for both IPv4 and IPv6 networking). Custom window sizes (configurable TCP window size for testing different network conditions and identifying optimal buffer sizes). Real-time interval reporting (periodic throughput, jitter, and loss statistics at configurable intervals during test). Bandwidth limiting (target bandwidth specification for UDP tests to measure packet loss under specific rates). Zero-copy mode (sendfile system call for reduced CPU usage on high-bandwidth links). Sctp support (SCTP protocol testing in addition to TCP and UDP). Linux, macOS, Windows, and BSD support with pre-compiled binaries. Omniiperf fork with enhanced analytics for high-performance computing networks.