Ubuntu Manpage: iperf3 - perform network throughput tests

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 and FreeBSD only).  On both the client and server you can
              set the local affinity by using the n form of this  argument  (where  n  is  a  CPU  number).   In
              addition,  on the client side you can override the server's affinity for just that one test, using
              the n,m form of argument.  Note that when using this feature, a process will only be  bound  to  a
              single CPU (as opposed to a set containing potentialy multiple CPUs).

       -B, --bind host
              bind to a specific interface

       -V, --verbose
              give more detailed output

       -J, --json
              output in JSON format

       --logfile file
              send output to a log file.

       -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

       -I, --pidfile file
              write a file with the process ID, most useful when running 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

--sctp use SCTP rather than TCP (FreeBSD and Linux)

-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). On platforms supporting the SO_MAX_PACING_RATE socket option (currently
only Linux), fair-queueing socket-level pacing, implemented in the kernel, will be used. On other
platforms, iperf3 will implement its own rate control.

--no-fq-socket-pacing
disable the use of fair-queueing based socket-level pacing with the -b option, and rely on
iperf3's internal rate control.

-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)

--cport port
bind data streams to a specific client port (for TCP and UDP only, default is to use an ephemeral
port)

-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)

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

-N, --no-delay
set TCP/SCTP 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)

-X, --xbind name
Bind SCTP associations to a specific subset of links using sctp_bindx(3). The --B flag will be
ignored if this flag is specified. Normally SCTP will include the protocol addresses of all
active links on the local host when setting up an association. Specifying at least one --X name
will disable this behaviour. This flag must be specified for each link to be included in the
association, and is supported for both iperf servers and clients (the latter are supported by
passing the first --X argument to bind(2)). Hostnames are accepted as arguments and are resolved
using getaddrinfo(3). If the --4 or --6 flags are specified, names which do not resolve to
addresses within the specified protocol family will be ignored.

--nstreams n
Set number of SCTP streams.

-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, --congestion algo
Set the congestion control algorithm (Linux and FreeBSD only). An older --linux-congestion
synonym for this flag is accepted but is deprecated.

--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

       A   list   of   the   contributors   to   iperf3  can  be  found  within  the  documentation  located  at
       http://software.es.net/iperf/dev.html#authors.