First, go to https. Delete the Cygwin shortcuts on the Desktop and Start Menu. In this tutorial you will learn: How to install iperf on Red Hat Enterprise Linux 8. Imitating the steps above execute iperf in the same manner, but this time we are going to give the iperf client different instructions. Bash/shell script you use to run the parallel connections. To transmit to multiple groups one can use iperf -c 239. There are hundreds of different commands available in a command line. You turn on the server with this command from the command prompt: iperf -s Yup, it's that simple. [[email protected] ~] # ifconfig - bash : ifconfig : command not found First thought may be, maybe /sbin/ isn’t in my PATH environment variable, but this isn’t the case. Iperf has a client and server functionality, and can measure the throughput between the two ends, either unidirectionally or bi-directionally. In other words, when doing an online speed test, you connect to a server on the Internet, owned by the provider of the test (like Ookla). Invoking iperf3¶. nProbe™ is available for a little fee, that’s used for running the project and funding the new developments. Parallel connections can be useful if you need to saturate Bidirectional testing. Is there any way of installing IPerf without being connected to the internet? I have an installation CD of FreeBSD version 8, would it contain the installation for IPerf. The command to run iPerf as a server is: iperf. I do not know what the bandwidth limitation is with this iPerf server. The iperf-openss7 package contains the iperf(1) program compiled to work with the OpenSS7 Linux Native Sockets version of SCTP. " Iperf was developed by NLANR/DAST as a modern alternative for measuring maximum TCP and UDP bandwidth performance. Step 2: Test The Network Speed Between Two Windows hosts. Once you have copied the binaries to the two servers, you have to first start the iPerf listener on one of the servers. net (IPv6) ping-90ms. Since I'm using this to test the speed of my home network, I need two machines up and running Linux on my LAN. The set of commands may vary dramatically between operating systems or applications. Once the package is installed, use the pfSense® webGUI to navigate to System > sudo , and define commands and who may run them. To run Iperf in server mode, I will type the command “iperf3. Everyone knows that CPU utiization in windows can be found out from Windows Task Manager. It should at least contain the specific iperf commands you run. Install iperf. If you want to try these tests for yourself you can use these commands for any public iPerf server: *Case sensitive. 7) You will get a Bandwidth and Jitter graph. codeblock} ldd /path/to/binary | grep libwrap In the following example the vsftpd program is checked for the libwrap shared library file. This command is similar to the standard iperf command. iperf is a tool for active measurements of the maximum achievable bandwidth on IP networks. Iperf is a command-line tool that allows you to test the bandwidth, any way you like. iperf was originally developed by NLANR/DAST. IPerf does not have to be installed, it runs simply in a command prompt window. The quality of a link can be tested as follows: - Latency (response time or RTT): can be measured with the Ping command. Parallel streams can help in some situations. -s, --server run in server mode -U, --single_udp run in single threaded UDP mode -D, --daemon run the server as a daemon. exe is located. iperf3 is a new implementation from scratch, with the goal of a smaller, simpler code base, and a library version of the functionality that can be used in other programs. How to measure network speed and bandwidth on iMX boards 2 minute read Introduction. The CentOS Extras repository includes a package to install EPEL, and is enabled by default. How to use iperf over mininet ? [Description] In this lab, I will show how to use iperf to do basic performance evaluation over mininet. The general idea is to run iPerf on two computers; one acts as the server, while the other takes as the client. To perform throughput surveys, click on the Adapter and Channel Config icon in the top right hand side corner and in the Devices window and select. It is capable of lightweight profiling. hdparm is a Linux command line utility that allows to set and view hardware parameters of hard disk drives. iperf was originally developed by NLANR/DAST. In this article, let us review 15 practical examples of rpm command. This is the result of a run without tcpdump. Generating Random Network Traffic with IPerf When you setup a nice bandwidth monitoring application, it is generally acceptable to just set it and forget it; the data you get is usually taken at face value. y) source files in the current directory. There's a number of online speed test websites, but they are all intended to test residential connections of less than 100Mb. It can be used to chart network throughput over time. On the end hosts ("sender" and "receiver"), install the iperf network testing tool, with the command. The iperf tool is useful for doing so. To use IPerf to test your network speed perform the following: On one end run IPerf as the server: iperf -s On the other end run IPerf as the client including the name or ip address of the iperf server. The server runs on the remote host and listens for connections from the client. This is a small "How to" for checking a service is running in the server or not. This app will not be useful unless you have a second phone or computer to use as an iPerf client/server. Iperf allows the tuning of various parameters and UDP characteristics. • Monitored traffic using network testing tool such as iperf and wireshark. exe -s from the Iperf directory. net (IPv4) ping6. The operating system does not matter, while you are using iperf. 02 Network performance measurement graphical tool JPerf Iperf command: I -p 5001 s s s s s s s s s s s 0. Test the VPN throughput for TCP traffic: iperf -c -P <2 x number of CPU cores> -e -m. Install Iperf and Test Network Throughput,Speed/Other Statistics September 19, 2014 Updated September 19, 2014 LINUX HOWTO , MONITORING Iperf is a network testing tool that can create TCP and UDP data connections and measure the throughput of a network that is carrying them. exit by using `ctrl + z` and kill iperf using `pkill -9 iperf`. 102, TCP port 5001 and the iperf server is listening for connection on TCP port TCP but that is it. 13mb/sec en ftp du A au site B qui est interne par un lien 10mb. iperf was originally developed by NLANR/DAST. > Download (. 2 -i1 -u -p50001, I get the following errors. This rate is very comparable to the rates we observed above in our load test using SQL Server. Tools like iperf are useful to check the performance of a network real quick, by comparing the achieved bandwidth with the expectation. 0K -f m -t 30 Server address. iperf's Transfer column is in MebiBytes: 1,048,576's of 8-bit Bytes. One of the primary tools that is used across the landscape today in determining network bandwidth and running throughput/speed tests is iPerf. Note that the IP address on the server side must be included in the command. iperf - Linux command to measure your network bandwidth - man page - September 25, 2007 IPERF(1) User Commands IPERF(1). *Iperf runs on port 5201 by default. The iperf application is not installed by default, but it is provided by most distributions' package manager. There's a number of online speed test websites, but they are all intended to test residential connections of less than 100Mb. The Iperf tool and DD net iperf command can be used for troubleshooting the following issues: Backup or restore slow using CIFS/NFS/DDBoost over IP, between media server and DD. Imitating the steps above execute Iperf in the same manner, but this time we are going to give the Iperf client different instructions. I can see that the UE has attached and it successfully receives attach complete. After the project, I figure this App may benefit other folks who are in the same situation, so I have polished the App a little and made it public here. Among its goals were a smaller, simpler code base (compared to its predecessor, iperf2) and a library version of the functionality that can be used in other programs. iperf3 -s -B 192. ‎This app is an iOS port for iperf3, which is the most commonly used network testing and performance computation tool. Any of my search term words; All of my search term words; Find results in Content titles and body; Content titles only. Jperf or Xjperf (both of them are the same thing. iperf is a tool for performing network throughput measurements. Iperf is a modern alternative for measuring TCP and UDP bandwidth performance, allowing the tuning of various parameters and characteristics. On the server side, from a command prompt window enter “start /node 2 /affinity 0xAAAA iperf -s” from the folder in which iperf resides. After the project, I figure this App may benefit other folks who are in the same situation, so I have polished the App a little and made it public here. To perform an iperf test the user must establish both a server (to discard traffic) and a client (to generate traffic). This should be the same in both client and server. On the other hand, we use iperf on UDP connection. 7 -p 8910 -T 10 -b 1 -i 5 -t 1200 The receiver - 128. Iperf is very powerful and can easily generate enough traffic. Exit focus mode This section describes Xperf command-line options and actions. Iperf is super easy to use. To configure two VMs with tap devices on non-DPDK OvS bridge (br0), refer to the instructions in the document Open vSwitch with KVM. The iPerf application contains both client and server functionality. It can be used to analyze both TCP and UDP traffic. Iperf can be used in two modes, client and server. This command is similar to the standard iperf command. On the Advanced tab, set both Recv Segment Coalescing (IPv4). Download the iperf3 binary zip, unzip to a known location and open a command prompt in the folder where iperf3. Imitating the steps above execute iperf in the same manner, but this time we are going to give the iperf client different instructions. A key point to remember when testing bandwidth with Iperf is that Iperf consumes all bandwidth available between client/server via TCP, regardless of LAN, WAN, or VPN connection. In the Network and Sharing Center of the guest operating system’s Control Panel, click the name of the network adapter. -t specifies time in seconds for the test. It is the industry standard tool for checking the interface and uplink and port speeds that IaaS providers (aka Cloud companies like IBM Softlayer, Rackspace, AWS) advertise. - On the Demo board , I run iperf -c www. 13mb/sec en ftp du A au site B qui est interne par un lien 10mb. This is done with the cd Downloads command. And those who look only to the past or the present are certain to miss the future. 10 sed command examples are discussed in this post. To install the EPEL release package, run the following command:. The lsof (LiSt Open Files) command lists all open files and sockets. It is particularly useful when experiencing network speed issues, as you can use iPerf to determine which server is unable to reach maximum throughput. The iperf application is not installed by default, but it is provided by most distributions' package manager. gz [email protected] ring2014a tar xzvf ape rf-3. 4 thoughts on " Test network performance with the Iperf tool " Kathy January 5, 2012. They run either CentOS or Ubuntu Linux. It supports tuning of various parameters related to timing, protocols, and buffers. how to troubleshoot performance issues in linux. Please note that the option commands are case sensitive. An advantage of using the nmap command is that the traceroute will use a discovered open port if available to perform the traceroute. iperf's Transfer column is in MebiBytes: 1,048,576's of 8-bit Bytes. It’s open source and cross platform supports variety of operating system including Microsoft window, Linus, UNIX, Apple Etc. To stop Iperf on the server or client side enter Ctrl+C. Hit return, it will begin to listen for any connections, see below. To use iPerf, you have to use at least two servers to test the bandwidth. Run the iperf server. How to use iperf over mininet ? [Description] In this lab, I will show how to use iperf to do basic performance evaluation over mininet. The network link is delimited by two hosts running Iperf. 30", the "-c" means to set PC B as Iperf client, and the IP address behind "-c" is the IP address of the server. iperf static build arm cross compile commands I am using the latest iperf version, iperf3. And also other operating system. What is iPerf / iPerf3 ? iPerf3 is a tool for active measurements of the maximum achievable bandwidth on IP networks. Running iperf. The Priority List specifies which queue a packet will be placed in and (optionally), maximum length of different queues. Once the package is installed, use the pfSense® webGUI to navigate to System > sudo , and define commands and who may run them. I was aware that Iperf is a good enough tool to generate and measure multicast and unicast traffic but support for SSM was missing from current version. About the App. [Windows] How do I used iPerf in Windows 7? I see that iperf seems to be a linux app? Is there anything I can use to compare my home network over wireless versus over powerline? Open a command. The iperf executable is located at /usr/local/bin/iperf on every ONL host. 0K -f m -t 30 Server address. Been a fan of iperf for years, so will prob keep this current when new versions come out since doesn't seem like anyone else is posting up the windows builds, etc. En effet, ce logiciel de mesure de performance réseau, diponible sur de nombreuses plateformes (Linux, BSD, Mac, Windows), se présente sous la forme d'une ligne de commande à executer sur deux machines disposées aux extrémités du réseau à tester. Since we are using the same key for both, we have already ensured the iperf-keypair. I imagined Powershell or by extension. Some usefull shell commands. Test with download files from FTP or HTTP Testing on a Linux server Within Linux you can tell wget to store large files in "/dev/null". How do I check the speed between the two Linux servers using command line options for private. In order to acquire maximum or rather improved network performance, you need to increase the throughput as well as latency of. Of course, there are Iperf versions for UNIX, Linux, BSD, MAC OS X, and Solaris. exit by using `ctrl + z` and kill iperf using `pkill -9 iperf`. Worthy of mention is the fact that it can measure both TCP and UDP performance. Menu Iperf3 Command and Option 06 September 2015 on Linux. In the Network and Sharing Center of the guest operating system’s Control Panel, click the name of the network adapter. " This tool has to configure server side and client side to complete a test. To transmit to multiple groups one can use iperf -c 239. To start the iperf server in UDP mode, use iperf -sDu as the u specifies UDP; the startup message should indicate that the server is listening for UDP datagrams. Iperf reports bandwidth, delay jitter, datagram loss. " Iperf was developed by NLANR/DAST as a modern alternative for measuring maximum TCP and UDP bandwidth performance. We have several methods to install Iperf on Linux including compiling from source code or install using my favorite Linux tool, yum. It has many of the same features, although it does not yet do multicast. Get the tcp ones working right, and I'd ignore the UDP results. net -i2 -t 20 Client connecting to IPerf. 2 -u -b 60M -k 20K Results. The user can run the iPerf application using the command prompt on a computer and the customized iPerf implementation on the wireless board to measure the throughput performance. Hping3 is another computer networking tool that you will use. txt & It is therefore possible to insert another command by injecting it in the "perf_measure_server_ip" parameter and. The client can then connect using the following command. These commands define a window size that is large enough to indicate whether the network is a potential cause of latency issues. Iperf can measure the throughput of a network, Iperf operates in a client and server mode. To run the commands as administrator, right-click on the shortcut and choose Run as administrator. 00 KByte (default. iperf can do multiple parallel streams as HP suggested, but it's the -P option. Network tuning and assessment with iperf test. Can someone tell me how to setup iperf on pfsense so i can test throughput to my clients antennas? I want the iperf server to be pfsense, and want to test thoughput to the clients antennas IP address. Good! The test using iperf running and connect perfect. This can be a bit tricky as Ubuntu seems to have version 2 of iperf in their default repository list. If it fails again, kill iperf using the above command and repeat step 1 again. If the latter form is used, the last hostname specified becomes. Right-click on Command Prompt and click Run as administrator. sudo apt-get install nsnake. Collect the following values from the output: VPN TCP iperf (fw1 to fw2) VPN TCP iperf (fw2 to fw1). 20 Awesome Nmap Command Examples Posted on Tuesday December 27th, 2016 Tuesday March 21st, 2017 by admin In this tutorial you’ll fined 20 basic examples of Nmap command usage. Plus, it also allows you to tune various parameters related to Timing, Buffers, and Protocols (TCP, UDP, SCTP, etc. Clear Output on each Iperf Run Ll JPerf 2. Using a completely different set of computers I was getting very similar results with them connected via a Gigabit link. Goal of the Webinar Demonstrate and educate how to test bandwidth performance with iPerf. The application is a frontend for Iperf, a popular command-line utility for bandwidth measurements. 10 in my cluster). Aptitude is an Ncurses and command-line based front-end to numerous Apt libraries, which are also used by Apt, the default Debian package manager. I tried couple of sites but couldnt understand how to use it. Test run: sudo lsof -i TCP. To transmit to multiple groups one can use iperf -c 239. Past the first CLI argument, node names are automatically replaced with corresponding IP addrs. You can use the -T option with iperf3 to add a string to the start of each line of iperf, though unfortunately, if that string contains a command (such as date) it will only use the date when the command was initially run. Whoever is seeing “Connection refused” on their screen needs to tell the other person to take a look at their port-forwarding and computer-firewall configuration. 3- LAN client / Server. perf is powerful: it can instrument CPU performance counters, tracepoints, kprobes, and uprobes (dynamic tracing). The presentation changes directories as Downloads bash shown. You have all of the basics now to begin testing the connections between different devices. The umount command is used to manually unmount filesystems on Linux and other Unix-like operating systems. [Windows] How do I used iPerf in Windows 7? I see that iperf seems to be a linux app? Is there anything I can use to compare my home network over wireless versus over powerline? Open a command. It should at least contain the specific iperf commands you run. iperf -c 192. Iperf is a tool that is used through command line to generate computer network traffic that resembles regular usage of a computer network. I use it on a daily basis and I believe it'll help expedite your network troubleshooting skills. To do this I will run the following command:. These commands define a window size that is large enough to indicate whether the network is a potential cause of latency issues. Iperf Commands for Network Troubleshooting Iperf is a network performance utility that can generate both TCP Parallel TCP connections. Typically, one acts as server and the other as client, where. Menu Iperf3 Command and Option 06 September 2015 on Linux. IPERF is a professional bandwidth test tool for qualifying performance of corporate networks and the Internet. Iperf is a utility for measuring maximum TCP and UDP bandwidth performance. The set of commands may vary dramatically between operating systems or applications. iperf: service: stop Other ¶ Method Module Controller Command Parameters iperf: instance: query. something like iperf -s -u -B 239. ini: Command file used by XMD to download the webserver file system and start execution of the lwIP raw mode software applications. We have several methods to install Iperf on Linux including compiling from source code or install using my favorite Linux tool, yum. Using putty. We will actually be using iperf3 for this tutorial. Iperf example commands. NOTE: By default, anything that does not match a priority-list is sent to Normal queue. Hi all! I was trying to install iperf, but yum claims there's no such program in the repo. It isn't working. Apache performance tuning for. Whether or not you use any form of hybrid cloud, I think it's important to at least know what's available, and how it's being used. It should at least contain the specific iperf commands you run. -t specifies time in seconds for the test. This is a good way to measure raw throughput on the storage system. While building the iperf command, a specific payload can be sent to the main. See also https://github. These commands may be used to configure, to troubleshoot your network or to obtain some more information all via the terminal in Linux. Iperf reports bandwidth, delay jitter, datagram loss. Exit focus mode This section describes Xperf command-line options and actions. However when I try to start iperf on either side by executing the command iperf -c 172. txt This command sets the client to reach out to the specified IP address for a test of 3 minutes (180 seconds). , length of time to transmit (with -t), number of parallel connections (with -P), and other parameters if you specify any. pem file has the correct permissions and can skip that step and immediate connect to the instance (be sure to update the following command with the proper hostname for this instance): ssh -i "iperf-keypair. This app is simple command line interface which requires us to input iPerf commands in order to execute the test. Of course, there are Iperf versions for UNIX, Linux, BSD, MAC OS X, and Solaris. exe -u -c " command on the client side. To do this I will run the following command:. On the TX side run “start /Node 2 /Affinity 0xAAAA iperf -c -P 8 -t -w1M *We will be running the commands vice versa so make sure to take note of the results. The TCP window size can affect the results of an IPERF test and mislead a user on a network's performance capabilities. 7) You will get a Bandwidth and Jitter graph. The adb command facilitates a variety of device actions, such as installing and debugging apps, and it provides access to a Unix shell that you can use to run a variety of commands on a device. Interestingly, tcdump causes a significant slowdown, which you can see for yourself. Similar Software for Mac. By default it will send a very small amount of data. A filesystem in this context is a hierarchy of directories that is located on a single partition (logically independent section of a hard disk drive) or other device, such as a CDROM, DVD, floppy disk or USB key drive, and has a single filesystem type (i. $ sudo apt install iperf -y. Use arrow keys to move the snake and feed it. For each test it reports the measured throughput / bitrate, loss, and other parameters. Everybody probably heard of this little and great command line utility that is used to test the reachability of a host on an Internet Protocol (IP) network. Jperf can be associated with Iperf to provide a graphical frontend written in Java. Note: If you get ‘#’ after typing adb shell, you are already get root access on the phone, no need to type su. To install the iperf tool, you first need to install the EPEL repository. Iperf is a very useful utility for network troubleshooting. This also includes the header files and. There are roughly 8. Before running a test you will need to make of the hosts the iperf server. Up to 25 Mbps Iperf Throughput @ 8 MHz channel (-78 dBm) Up to 2 Mbps IPerf Throughput @ 4 MHz channel (-102 dBm) Extremely small foot print and very lightweight Serial Communication Port Dual 10/100 Ethernet Ports (LAN/WAN) Supports Point -toPoint and Point Multipoint Networks Master, Remote, Relay Operating Modes. By default, Windows will decrease the TTL by 128 and Ubuntu Linux by 192. The command to run iPerf as a server is: iperf. It comes in handy for network performance tuning operations. It is particularly useful when experiencing network speed issues, as you can use iPerf to determine which server is unable to reach maximum throughput. ‎This app is an iOS port for iperf3, which is the most commonly used network testing and performance computation tool. iperf - Linux command to measure your network bandwidth - man page - September 25, 2007 IPERF(1) User Commands IPERF(1). iperf命令 是一个网络性能测试工具。iperf可以测试TCP和UDP带宽质量。iperf可以测量最大TCP带宽,具有多种参数和UDP特性。iperf可以报告带宽,延迟抖动和数据包丢失。利用iperf这一特性,可以用来测试一些网络设备如路由器,防火墙,交换机等的性能。. 4 thoughts on " Test network performance with the Iperf tool " Kathy January 5, 2012. Most times the stations refuse to do a speed test to the access point but the access point can do a speed test to. Change to this directory and one can run iperf. Figure 12 – Find a File 8. Commit Score: This score is calculated by counting number of weeks with non-zero commits in the last 1 year period. In order to run iperf you must have a server running on the machine which you iperf to. On the client side, simply use the command as shown in the image below to run Iperf in client mode. To install the iperf tool, you first need to install the EPEL repository. We will begin by setting up two new EC2 instances using the Amazon Linux AMI from the EC2 Management Console on AWS. One side needs to be set up as the iperf server to accept connections. You need to setup IPerf on both ends to perform testing. A filesystem in this context is a hierarchy of directories that is located on a single partition (logically independent section of a hard disk drive) or other device, such as a CDROM, DVD, floppy disk or USB key drive, and has a single filesystem type (i. For details, please use iperf -help to check. Been a fan of iperf for years, so will prob keep this current when new versions come out since doesn't seem like anyone else is posting up the windows builds, etc. Running Example Project with IAR The iot_sdk_demo project, along with other example projects, communicates the output through mbed Serial Port. Iperf is a command-line tool that allows you to test the bandwidth, any way you like. 13a so it's a good time to add the multiple group join if it's useful. In the command prompt on the client side, run this command: iperf -c 10. It is also included in the Linux kernel, under tools/perf, and is frequently updated and enhanced. I have this setup on a server called DC1 and a windows 10 computer called PC1. Iperf is an easy-to-use free command line tool that allows you to measure your. If not specified. tgz (NetBSD 8. And Type "iperf -c 192. SSH Speed Test command - posted in Barracuda NextGen and CloudGen Firewall F-Series: I was working with support and the technician got into SSH and ran a command line script (I think it was a script) to test bandwidth. The iperf application is not installed by default, but it is provided by most distributions' package manager. Menu Iperf3 Command and Option 06 September 2015 on Linux. 3) Execute the command " iperf. run_iperf_ser. Install iperf. 1 -P 99 --incr-dstip I've been doing a bit of fix ups in iperf 2. The following example shows the configuration of peak traffic shaping. This way files are downloaded into the RAM and not into the hard drive. gz The presentation opens the command prompt as shown. For each test it reports the measured throughput / bitrate, loss, and other parameters. One of the first things that you might notice when logging into a new CentOS 7 minimal installation is there is no ifconfig command. Jperf or Xjperf (both of them are the same thing. Menu Iperf3 Command and Option 06 September 2015 on Linux. The source - 128. Hit return, it will begin to listen for any connections, see below. Good! The test using iperf running and connect perfect. Iperf is a commonly used network testing tool that can create Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) data streams and measure the throughput of a network that is carrying them. The adb command facilitates a variety of device actions, such as installing and debugging apps, and it provides access to a Unix shell that you can use to run a variety of commands on a device. On its own, the sleep command isn't very useful, but as part of a script, it can be used in many different ways. trying to get iperf to run on solaris 9. 5+dfsg1-2_amd64 NAME iperf - perform network throughput tests SYNOPSIS iperf-s [options] iperf-c server [options] iperf-u-s [options] iperf-u-c server [options] DESCRIPTION iperf is a tool for performing network throughput measurements. My server has an intel X540-AT2 network card with 2 10G interfaces. Measuring Network Bandwidth using Iperf and Docker. 10, run the following command in server side. 2 -i1 -u -p50001, I get the following errors. Here is how the command line output looks for the two versions and for UDP and TCP tests, at their basic forms without any advanced options. If the connection is successful, the iperf log should be able to be seen in the linux machine terminal. iPerf on the command line iPerf for bandwidth monitoring. 4 thoughts on " Test network performance with the Iperf tool " Kathy January 5, 2012. After running this you will get an ouput that looks something like this:. iPerf is a widely used tool for network performance measurement and tuning. Once you are used to htop, you’ll never go back to top again. These commands define a window size that is large enough to indicate whether the network is a potential cause of latency issues. Because of its long history and many iterations, I have always found it a little confusing to get started with. Suppose you have edited your httpd. gz The presentation opens the command prompt as shown. The presentation changes directories as Downloads bash shown. I have setup total four servers in cloud based data center. July 7, 2019 at 6:06 pm. In other words, when doing an online speed test, you connect to a server on the Internet, owned by the provider of the test (like Ookla). The set of commands may vary dramatically between operating systems or applications. The default TCP window size being 85,3 kB (and even 20 kB on the client side that is sending the data), there is a side effect of TCP ruled by this formula : TCP Bandwidth (bps) = TCP Window (B) * 8 / RTT (s).