Iperf Guide

Iperf  is a tool to measure network performance. It measures maximum TCP bandwidth and bandwidth performance in UDP test. In this post you will find the main Iperf optins and some exampe. You can perform test between two host (pc or server) one wil be “server” side of the test and the other will be “client” side.


Common parameters:

test UDP (optional, if not indicated TCP test will be performed)
-s server side
-c client side, it is followed by server ip address
test bandwidth (only with -u option, for UDP test, defaul is 1Megabit). TCP test will measure maximum TCP bandwidth
-p test port
-t  duration in seconds
time interval between two “live” output during test
tcp windows size, “Sets the socket buffer sizes to the specified value. For TCP, this sets the TCP window size. For UDP it is just the buffer which datagrams are received in, and so limits the largest receivable datagram size.” (from official documentation)
-P number of connection, to be set in server side. After this number of test the connection will be drop (for instance with -P 1 after the first test the connection will be closed)
Bind. On client side it is the ip address of outbound interface, On server side it is the ip address of inbound interface. Useful in case of equipments with multiple interfaces.
for DSCP tag only on client size. Specify the TOS value in hex. (example:  http://www.tucny.com/Home/dscp-tos)

IPERF example

We want to perform a test between MyTerminal and one server called PigServer:

Port: 5501
Duration: 5 minutes (300 sec)
Band: 2M


In this case we don’t need to specify the bandwidth, it will be calculated by the test.  Tests have to be started always on server side.



This is the OUTPUT of the test (measured bandwidth is 2.13 Mbits/sec):


There is not connection between client and server during UDP, (so do not surpise if client send flow to server even if server doesn’t receive anything)



Output (you can see bandwidth, jitter and Packet Loss):

itg and iperf

measure network performance with itg and iperf

It could be intresting: D-ITG and iperf and itg difference

Usefull Links:

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