sudo apt-get install iperf
$ sudo yum install epel-release
$ sudo yum update
$ sudo yum install iperf
$ iperf -s -f m // server mode, bandwidth unit : MB
$ iperf -s -p 1234 // server mode, using port 1234
$ iperf -c ipadress -p 1234 -f M // client mode, send test packet, unit MB/s, using port 1234