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

ESnet                                             January 2015                                          IPERF(1)