NAME

       iperf3 - perform network throughput tests

SYNOPSIS

       iperf3 -s [ options ]
       iperf3 -c server [ options ]

DESCRIPTION

       iperf3  is  a tool for performing network throughput measurements.  It can test either TCP
       or UDP throughput.  To perform an iperf3 test the user must establish both a server and  a
       client.

GENERAL OPTIONS

       -p, --port n
              set server port to listen on/connect to to n (default 5201)

       -f, --format
              [kmKM]   format to report: Kbits, Mbits, KBytes, MBytes

       -i, --interval n
              pause n seconds between periodic bandwidth reports; default is 1, use 0 to disable

       -F, --file name
              client-side:  read  from the file and write to the network, instead of using random
              data; server-side: read from the network and write to the file, instead of throwing
              the data away

       -A, --affinity n/n,m
              Set  the CPU affinity, if possible (linux only).  On both the client and server you
              can set the local affinity; in addition, on the client side you  can  override  the
              server's affinity for just that one test, using the n,m form.

       -V, --verbose
              give more detailed output

       -J, --json
              output in JSON format

       -d, --debug
              emit debugging output.  Primarily (perhaps exclusively) of use to developers.

       -v, --version
              show version information and quit

       -h, --help
              show a help synopsis

SERVER SPECIFIC OPTIONS

       -s, --server
              run in server mode

       -D, --daemon
              run the server in background as a daemon

       -1, --one-off
              handle one client connection, then exit.

CLIENT SPECIFIC OPTIONS

       -c, --client host
              run in client mode, connecting to the specified server

       -u, --udp
              use UDP rather than TCP

       -b, --bandwidth n[KM]
              set target bandwidth to n bits/sec (default 1 Mbit/sec for UDP, unlimited for TCP).
              If there are multiple streams (-P flag), the bandwidth limit is applied  separately
              to  each  stream.   You can also add a '/' and a number to the bandwidth specifier.
              This is called "burst mode".  It will send the  given  number  of  packets  without
              pausing,  even  if that temporarily exceeds the specified bandwidth limit.  Setting
              the target bandwidth to 0 will disable bandwidth limits  (particularly  useful  for
              UDP tests).

       -t, --time n
              time in seconds to transmit for (default 10 secs)

       -n, --bytes n[KM]
              number of bytes to transmit (instead of -t)

       -k, --blockcount n[KM]
              number of blocks (packets) to transmit (instead of -t or -n)

       -l, --length n[KM]
              length of buffer to read or write (default 128 KB for TCP, 8KB for UDP)

       -P, --parallel n
              number of parallel client streams to run

       -R, --reverse
              run in reverse mode (server sends, client receives)

       -w, --window n[KM]
              window  size  /  socket  buffer size (this gets sent to the server and used on that
              side too)

       -B, --bind n[KM]
              bind to a specific interface or multicast address

       -M, --set-mss n
              set TCP maximum segment size (MTU - 40 bytes)

       -N, --no-delay
              set TCP no delay, disabling Nagle's Algorithm

       -4, --version4
              only use IPv4

       -6, --version6
              only use IPv6

       -S, --tos n
              set the IP 'type of service'

       -L, --flowlabel n
              set the IPv6 flow label (currently only supported on Linux)

       -Z, --zerocopy
              Use a "zero copy" method of sending data, such as sendfile(2), instead of the usual
              write(2).

       -O, --omit n
              Omit the first n seconds of the test, to skip past the TCP slow-start period.

       -T, --title str
              Prefix every output line with this string.

       -C, --linux-congestion algo
              Set the congestion control algorithm (linux only).

       --get-server-output
              Get  the output from the server.  The output format is determined by the server (in
              particular, if the server was invoked with the --json flag, the output will  be  in
              JSON  format, otherwise it will be in human-readable format).  If the client is run
              with --json, the server output is included  in  a  JSON  object;  otherwise  it  is
              appended at the bottom of the human-readable output.

AUTHORS

       Iperf was originally written by Mark Gates and Alex Warshavsky.  Man page and maintence by
       Jon Dugan <jdugan at  x1024  dot  net>.   Other  contributions  from  Ajay  Tirumala,  Jim
       Ferguson,  Feng  Qin,  Kevin  Gibbs,  John  Estabrook  <jestabro at ncsa.uiuc.edu>, Andrew
       Gallatin <gallatin at gmail.com>, Stephen Hemminger <shemminger at linux-foundation.org>

SEE ALSO

       libiperf(3), http://software.es.net/iperf