IPerf is a command line program for measuring the performance of networks. JPerf is developed in a Java graphical user interface for IPerf. This guide describes the measurement of the bandwidth of networks by JPerf 2.0.2.
The Java application JPerf runs on Windows, Linux and Apple Mac OS X. For a measurement there are always two networked stations required. As long as both stations are to build an IP connection between the leaves, the type of network is irrelevant. The measurement may be in the local area network (LAN) and over the Internet (ADSL, VDSL, Cable Internet and UMTS) and is also carried out wireless internet access.
JPerf does not for the measurements on the hard disk. The performance of the disk is thus not one in the measurements. In practice, the copying of files over the network that is always slower than the JPerf identified with values.
The free program can be downloaded at Google Code.
Installation
Since JPerf a Java interface for IPerf, it always requires IPerf and a JRE.
Windows
On Windows no installation of JPerf is necessary. After unpacking the ZIP files can be launched directly jperf.bat. IPerf.exe The required is included in the ZIP file.
Linux
JPerf on Linux is also not required the installations. IPerf must be built from source using “configure; make; install” to be installed.
Apple Mac OS
The Apple also extends from the unpacking of the zip files. Only the file with the command “chmod u + x jperf.sh” executable needs to be done jperf.sh.
Additionally to JPerf must be still installed IPerf. In order to be able to compile IPerf on the Mac, the Apple developer tools must be installed. From the terminal can IPerf with the commands “. /configure; make; make install” to be translated and installed.
Measurement with JPerf
For all measurements a server and at least a Client are needed in each case. Over to start select and operate the server with “Choose IPerf the mode” the option server the switching surface “run IPerf!”. This starts IPerf in server mode with default parameters. The server is now taking connections on TCP port 5001 forward. If this port is blocked by a firewall, for example, you can customize the port number accordingly.
JPerf server on Windows 7
On a second machine, we start a JPerf client. In the “Server address” must be the IP address of the server JPerf be entered. All other parameters can remain unchanged for a first test. Starting the test with “Run IPerf!”.
JPerf in client mode under Windows 7
For the duration of the measurement (10 seconds) clients are now transferred to the data from the server. It takes the measurements therefore always a kind place to upload. The test data are rejected by the server. The achieved bandwidth is graphically illustrated in the diagram. Under the chart is the text output of the readings.
JPerf options
The measurements can be controlled by a variety of options with. With the default values is often the maximum bandwidth of a connection does not reach.
Application Layer options
In the LAN usually ranges from a measurement over 10 seconds. For longer measurements here, the length of transmission can be set. This can for example, measurements in the wireless mobile client with a useful one.
Application Layer Options from JPerf
For current networks, the display of values (output format) will be placed on MBits. The interval for the display of intermediate (Report Interval) can be increased according to measurements at long.
Transport Layer Options
In the Transport Layer Options, the settings for the protocols TCP, and UDP can be changed. JPerf set settings in the appropriate parameters at the IPerf.
With Buffer Length can be set from IPerf used cache. Sometimes this larger values lead to better measurements.
The TCP window size indicates how much data transmitter may send without an acknowledgment (ACK) to obtain from the recipient. It is, therefore, the data “in flight” (the road) can be to a TCP connection to fully, the TCP window size to be greater than the product of bandwidth and duration (Bandwidth Delay Product) of the line. Fast WAN connections can be at quite a few megabytes in the line be on the move and must be the TCP window size to be adjusted in accordance JPerf.
A change in the maximum segment size MSS is usually not necessary. Just bring a disabling the Nagle algorithm and TCP No Delay no significant change in the readings.
Settings for TCP and UDP
Measuring the transmission rate with the connectionless UDP must be elected at the desired bandwidth for client. The client then creates a UDP stream at the set speed. The JPerf displayed in MB / sec, however, are Mbit / s. In the output of IPerf below the graph display is incorrect.
When measuring with UDP is still the bandwidth of the jitter (the variance of the term) and the packet loss shown in addition. The power of a UDP connection is crucial for the transmission of VoIP.