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 Home » Freeware Downloads » Network Monitoring and Hacks » IPerf2 v2.1.9   
File - Download IPerf2 v2.1.9

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IPerf2 v2.1.9

A tool that measures network performance of TCP/UDP including latency

A network traffic tool for measuring TCP and UDP performance with metrics around both throughput and latency. The goals include maintaining an active iperf code base across a broad set of platforms and operating systems. This is a multi-threaded design which scales with the number of CPUs or cores within a system.

See the manual page for more features and usage.

  • Fix portability, compile and tested with Linux, Win10, Win7, WinXP, MacOS, Android and some set-top box OSs.
  • Require -u for UDP (-b no longer defaults to UDP)
  • Improved performance
  • Enhanced reporting with -e
  • Support smaller report intervals (100 us or greater, configure --enable-fastsampling for high precision interval time output)
  • Support SO_RCVTIMEOUT for server reports regardless of no packets
  • Support SO_SNDTIMEO on send so socket write won't block beyond -t or -i
  • Support SO_TIMESTAMP for kernel level packet timestamping
  • Support end/end latency in mean/min/max/stdev format (UDP) (-e required) (assumes client and server clocks synched, e.g by Precision Time Protocol to an OCXO oscillator per Spectracom)
  • Fixes to bind so OS can auto assign source port
  • Add local port to bind support (-B option) using colon as separator (v4) or brackets (v6) e.g. iperf -c -B (v4) or for v6, iperf -V -c 2001:e30:1401:2:d46e:b891:3082:b939 -B [2001:e30:1401:2:d46e:b891:3082:b940]:6001
  • Support TCP rate limited streams (via the -b) using simplified token bucket
  • Support packets per second (UDP) via pps as units, (e.g. -b 1000pps)
  • Display PPS in both client and server reports (UDP) (-e required)
  • Support realtime scheduler as a command line option (--realtime or -z, assumes proper user privileges)
  • Improve client tx code path so actual tx offered rate will converge to the -b value
  • Improve accuracy of microsecond delay calls (in platform independent manner) (Use of Kalman filter to predict delay errors and adjust delays per predicted error)
  • Display target loop time in initial client header (UDP)
  • Fix final latency report sent from server to client (UDP)
  • Include standard deviation in latency output
  • Suppress unrealistic latency output using (-/-/-/-)
  • Use clock_gettime() in critical sections, if available, replacing gettimeofday() calls
  • TCP write and error counts (TCP retries and CWND for linux) (-e required)
  • TCP read count, TCP read histogram (8 bins) (-e required)
  • TCP RTT and CWND values in client reports (-e required, Linux only, RTT units microseconds)
  • Added support for -t on the Server (Listener) so servers/listener can be set to timeout and exit
  • Add ipv6 link local support (e.g. iperf -c fe80::d03a:d127:75d2:4112%eno1)
  • Default ipv6 UDP payload to 1450 bytes per one ethernet frame per payload
  • -V on server will accept both IPv4 and IPv6 traffic flows
  • Isochronous traffic support (via --isochronous) and frame bursts with variable bit rate (vbr) traffic and frame ids
  • Multicast SSM support for both v4 and v6 using -H or -ssm-host, e.g. iperf -s -B ff1e::1 -u -V -H fc00::4
  • Latency histograms for both packets and frames (e.g. --udp-histogram=10u,200000, 0.03, 99.97)
  • Ethernet frame length checks with --l2checks on the client (UDP only and requires systems that support AF_PACKET)
  • Server (read) -b support for TCP (via token bucket)
  • UDP write counters and write error counters (requires -e)
  • Python asyncio code to manage multiple iperf sessions (found in the flows directory)
  • Support for timed transmit starts per --txstart-time <unix.epoch time>
  • Support for client incrementing the destination ip with -P via --incr-dstip
  • Support for varying the offered load using a log normal distribution around a mean and standard deviation (per -b <mean>,<stdev>),
  • Honor -T (ttl) for both unicast and multicast
  • Added network power to TCP client and UDP server enhanced output (netpower = throughput / RTT or throughput / end2end delay on server)
  • Add TCP connect time to connected to message
  • Add support for SO_MAX_PACING_RATE socket option using --fq-rate <value>
  • Add configure support for --enable-fastsampling, allowing 100 microsecond report intervals
  • Add support for --trip-time on client, requires -e on both client and server and synchronized clocks
  • UDP uses 64 bit sequence numbers (though still interoperates with 2.0.5 which uses 32b seq no.)

2.1.9 (as of March 14th, 2023)
fixed traffic setitimer to use uintmax_t vs int, supporting large values
--bounceback officially supported (including Windows) for repsonsiveness test scenarios
deprecated --bounceback-congest introduced in 2.1.8, replaced by --working-loads
--working-loads support generalized; works with --bounceback, --connect-only &amp; --burst-period
default TCP_NOTSENT_LOWAT with the --working-loads concurrent traffic
add support for GMT time formatting via --utc option
--trip-times will auto set TCP_NOTSENT_LOWAT
CSV output fixes for reverse
CSV output regressions fixed per sum outputs using negative transfer ids
CSV output support with --enhanced
Fix to isoch wait_tick with Windows
fix support for --txstart-time with --bounceback
Add support for summing histograms in histogram sum outputs
Multiple sum report fixes per threading &amp; needing mutex protections
Jitter packet IPG calcluations ignore inter frame gaps
Isoch jitter output to use running value vs sampled value
Add support for --jitter-histograms
man page content updates
output isoch scheduling errors at end of isoch run
PRIdMAX fix for ARM systems
better work around in isochronous with Windows per early return of WaitForSingleObject()
fix SO_BINDTODEVICE regression
fix v6 source port parsing with -B and brackets
fix malloc error with --hideips
fixes for rate limited TCP with --trip-times
add support for TCL_NOTSENT_LOWAT with rate limited TCP
permit key now supports -P using listen() with a backlog, no longer single thread limited
fixes for zero valued permit-key
fixes for multiple permit-key regressions
fix token bucket delay with TCP await write
fix isMulticast test for ipv4 - previous logic indicate true for 240.x.x.x which is not multicast
fix regression on jitter calc - starts on second transit time
add cmsg for loop with UDP rx timestamp, cmsg processing best to use loop w/test
use stdout and exit(0) for -h and -v (vs stderr and exit(1))
add python facetime scripts
Fix single thread compile breakage
fix windows cross compile
multiple spelling error fixes in comments and man page

This download is for the Windows version. If you need the Linux version, download here.

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Downloads Views Developer Last Update Version Size Type Rank
1,598 2,781 Robert McMahon <img src=""border="0"> Jan 24, 2024 - 13:36 2.1.9 1.65MB EXE 5/5, out of 11 Votes.
File Tags
v2.1.9  IPerf2  
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