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.