How is bandwidth calculated?
From a quick test run on a linux box, using 1.7:
[terje --at-- tzu terje]$ iperf -c 172.25.25.100 -u -t 5 -f b -b 5000k
------------------------------------------------------------
Client connecting to 172.25.25.100, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size: 65535 Byte (default)
------------------------------------------------------------
[ 5] local 172.25.25.106 port 32781 connected with 172.25.25.100 port 5001
[ ID] Interval Transfer Bandwidth
[ 5] 0.0- 5.0 sec 3128160 Bytes 5001318 bits/sec
[ 5] Server Report:
[ 5] 0.0- 5.0 sec 3107580 Bytes 4954921 bits/sec 3.454 ms 14/ 2128 (0.66%)
[ 5] Sent 2128 datagrams
Looking at the figures, the client reports having transmitted
3128160 bytes. Apparently this is payload only, without 28 bytes
of UDP header. 3128160*8/5 = 5005056, which is close but not quite
correct. Is this due to timing issues?
However, on the wire data is transmitted with the headers, so it
should really be 2128 packets * 1498 bytes = 3187744, which becomes
3187744*8/5 = 5100390 bits/sec. Should there be an option to print the
data including headers? This concerns me, since I'm using iperf to test
network hardware.
--
Terje Krogdahl
"If it's a question of the network going down, we get helicopters, air
support, tanks - whatever we need," - Lieutenant Colonel Mims, Iraq