iperf is a command line tool for performing real-time network throughput measurements. It is a powerful tool for testing the maximum achievable bandwidth in an IP network.

Initial Setup
Server
First, connect to the router which you will use as the server
-s
run in server mode
-p
port to listen n (default 5001)
-f
traffic format to report
K
KBytes M
Mbytes G
Gbytesiperf -s -p 5111 -f K ------------------------------------------------------------ Server listening on TCP port 5111 TCP window size: 85.3 KByte (default) ------------------------------------------------------------
Client
Next, connect to the router/computer which you will use as the client.
-c
connect to the specified server
-p
port to connect to n (default 5001)
-f
traffic format to report
K
KBytes M
Mbytesiperf -c 172.30.6.110 -p 5111 -f K ------------------------------------------------------------ Client connecting to 172.30.6.110, TCP port 5111 TCP window size: 85.0 KByte (default) ------------------------------------------------------------ [ 3] local 192.168.199.138 port 51840 connected with 172.30.6.110 port 5111 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.1 sec 5248 KBytes 519 KBytes/sec
Reverse Mode
iperf -c 172.30.6.110 -p 5111 -f K -R ------------------------------------------------------------ Client connecting to 172.30.6.110, TCP port 5111 TCP window size: 85.0 KByte (default) ------------------------------------------------------------ [ 3] local 192.168.199.138 port 51842 connected with 172.30.6.110 port 5111 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.3 sec 6144 KBytes 598 KBytes/sec
UDP protocol
Server
iperf -s -p 5111 -f K -u ------------------------------------------------------------ Server listening on UDP port 5111 Receiving 1470 byte datagrams UDP buffer size: 41.1 KByte (default) ------------------------------------------------------------ [ 3] local 172.30.6.1 port 5111 connected with 172.30.6.101 port 36141 ------------------------------------------------------------
Client
iperf -c 172.30.6.1 -p 5111 -f K -f -u ------------------------------------------------------------ Client connecting to 172.30.6.110, TCP port 5111 TCP window size: 85.0 KByte (default) ------------------------------------------------------------ [ 3] local 192.168.199.138 port 51842 connected with 172.30.6.110 port 5111 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.3 sec 6144 KBytes 598 KBytes/sec
Server Results
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 3] local 172.30.6.1 port 5111 connected with 172.30.6.101 port 34011 [ 3] 0.0- 9.9 sec 1282 KBytes 130 KBytes/sec 8.960 ms 2147481861/2147482754 (1e+02%)