iperf

Notes on iperf

Available on rpmforge.

Basic throughput testing, TCP:

• run the server

# iperf -s

• run the client

# iperf -c 10.0.0.22
------------------------------------------------------------
Client connecting to 10.0.0.22, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[  3] local 10.0.0.251 port 46617 connected with 10.0.0.22 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.10 GBytes    944 Mbits/sec

It is popular to use iperf in udp mode to detect dropped packets. To do this:

• run the server in udp mode:

# iperf -s -u

• run the client in udp mode, rate-limited to 100 Mb/s:

# iperf -c 10.0.0.22 -u -b 100m -i 1

Beware that when using UDP, the client will send at either its local maximum rate or the defined rate -- even if the server can't deal with that volume of data, and what the server can't deal with will be reported as lost packets. This is not necessarily a problem with your network. (UDP packets get lost. That's life.)