The bandwidth argument (-w 350m) passed to iperf means that the effective transmission rate as measured by the application should be 350 Mbps which excludes the bytes in any encapsulation headers. In our case, there is an additional 28 bytes (20-byte IP header and 8-byte UDP header) that accounts for an additional 2% in the packet length.

iperf3 is a tool for measuring the achievable TCP, UDP, and SCTP throughput along a path between two hosts. It allows the tuning of various parameters such as socket buffer sizes and maximum attempted throughput. It reports (among other things) bandwidth, delay jitter, and datagram loss. iperf was originally developed by NLANR/DAST. iperf3 is a new implementation developed from scratch at the Iperf :: Anaconda Cloud conda install linux-64 v3.8.1; osx-64 v3.8.1; To install this package with conda run one of the following: conda install -c conda-forge iperf conda install -c conda Iperf version 1.7.0 - University of Arizona node2> iperf -s -w 130k ----- Server listening on TCP port 5001 TCP window size: 130 KByte ----- [ 4] local port 5001 connected with port 2530 [ ID] Interval Transfer Bandwidth [ 4] 0.0-10.1 sec 19.7 MBytes 15.7 Mbits/sec node1> iperf -c node2 -w 130k ----- Client connecting to node2, TCP port 5001 TCP window size: 129 KByte (WARNING: requested 130 KByte

It uses port 5001 by default, and the bandwidth it displays is from the client to the server. Each test runs for 10 seconds by default, but virtually every setting is adjustable. Once installed, simply bring up the command line on both of the hosts and run these commands. On the server side:

Iperf provides a tool to measure IP bandwidth using UDP or TCP. It allows for tuning various parameters, and reports bandwidth, delay jitter, and packet loss. It supports IPv6 and multicast. perf is a tool to measure maximum TCP bandwidth, allowing the tuning of various parameters and UDP characteristics. Network Throughput Testing with iPerf – geekdecoder Jan 09, 2019 linux - iperf - what is the meaning of bandwidth? - Stack

Iperf provides a tool to measure IP bandwidth using UDP or TCP. It allows for tuning various parameters, and reports bandwidth, delay jitter, and packet loss. It supports IPv6 and multicast. perf is a tool to measure maximum TCP bandwidth, allowing the tuning of various parameters and UDP characteristics.

# iperf -u -c server -b 1000M ----- Client connecting to 1.1.1.1, UDP port 5001 Sending 1470 byte datagrams UDP buffer size: 124 KByte (default) ----- [ 3] local 1.1.1.2 port 58097 connected with 1.1.1.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 1.10 GBytes 948 Mbits/sec [ 3] Sent 806540 datagrams [ 3] Server Report: [ ID