I'm running Iperf (vers 1.7.0, 13 Mar 2003, win32).
First, for TCP, I'm varying packet lengths and noticing some irregularity. I'm monitoring the ethernet traffic with Ethereal. When I send packets of specified length, the following packet sizes are sent before an ACK from the receiver is sent back:
Length Packets Sent Total Comments
4k 1460/1460/1176 4096
2k 1460/588 2048
1k 1024/1460/588 ?? Sometimes the first 1024 is sent, sometimes just the 1460 and 588
512 512/1460/76 ?? Sometimes the first 512 is sent, sometimes just the 1460 and 76
The first two results seem correct, the latter two results seem incorrect. Note for the latter two, the specified lengths are less than the MTU.
The commands that I use are (for length 4k):
for the server iperf -s -l 4k -P 1
for the client iperf -c 192.168.200.101 -l 4k -t 10
Isn't this operating incorrectly for the smaller lengths written?
Secondly, for UDP, the first interval always (using interval '-i 1') records a huge loss datagram number--more than total sent. However, it doesn't seem to affect the final count. Is it just a bug? See sample below.
Thirdly, for UDP, there are times during the intervals (using interval '-i 1') where the lost datagram number is negative. What does that mean (i.e., at 10, 19, 20, 29, 30, 31 sec)? Was the datagram just received in the different interval than transmitted? Others show more than were sent (i.e., at 18, 28 sec). What does that mean? See sample below.
Erik Nelson
Sample:
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1460 byte datagrams
UDP buffer size: 8.00 KByte (default)
------------------------------------------------------------
[900] local 192.168.200.101 port 5001 connected with 192.168.203.101 port 1964
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[900] 0.0- 1.0 sec 64.2 KBytes 526 Kbits/sec 7.709 ms 1632658025/ 45 (3.6e+009%)
[900] 1.0- 2.0 sec 67.0 KBytes 549 Kbits/sec 8.770 ms 0/ 47 (0%)
[900] 2.0- 3.0 sec 64.2 KBytes 526 Kbits/sec 8.332 ms 0/ 45 (0%)
[900] 3.0- 4.0 sec 59.9 KBytes 491 Kbits/sec 8.825 ms 0/ 42 (0%)
[900] 4.0- 5.0 sec 61.3 KBytes 502 Kbits/sec 9.705 ms 0/ 43 (0%)
[900] 5.0- 6.0 sec 49.9 KBytes 409 Kbits/sec 11.208 ms 0/ 35 (0%)
[900] 6.0- 7.0 sec 65.6 KBytes 537 Kbits/sec 7.482 ms 0/ 46 (0%)
[900] 7.0- 8.0 sec 59.9 KBytes 491 Kbits/sec 9.932 ms 0/ 42 (0%)
[900] 8.0- 9.0 sec 65.6 KBytes 537 Kbits/sec 7.591 ms 0/ 46 (0%)
[900] 9.0-10.0 sec 62.7 KBytes 514 Kbits/sec 531.064 ms 8/ 52 (15%)
[900] 9.0-10.0 sec 18 datagrams received out-of-order
[900] 10.0-11.0 sec 64.2 KBytes 526 Kbits/sec 94.138 ms -8/ 37 (-22%)
[900] 10.0-11.0 sec 8 datagrams received out-of-order
[900] 11.0-12.0 sec 67.0 KBytes 549 Kbits/sec 11.394 ms 0/ 47 (0%)
[900] 12.0-13.0 sec 58.5 KBytes 479 Kbits/sec 10.373 ms 0/ 41 (0%)
[900] 13.0-14.0 sec 61.3 KBytes 502 Kbits/sec 8.810 ms 0/ 43 (0%)
[900] 14.0-15.0 sec 65.6 KBytes 537 Kbits/sec 8.211 ms 0/ 46 (0%)
[900] 15.0-16.0 sec 67.0 KBytes 549 Kbits/sec 7.186 ms 0/ 47 (0%)
[900] 16.0-17.0 sec 62.7 KBytes 514 Kbits/sec 8.232 ms 0/ 44 (0%)
[900] 17.0-18.0 sec 64.2 KBytes 526 Kbits/sec 10.273 ms 0/ 45 (0%)
[900] 18.0-19.0 sec 59.9 KBytes 491 Kbits/sec 652.175 ms 43/ 34 (1.3e+002%)
[900] 18.0-19.0 sec 7 datagrams received out-of-order
[900] 19.0-20.0 sec 64.2 KBytes 526 Kbits/sec 1085.958 ms -22/ 22 (-1e+002%)
[900] 19.0-20.0 sec 22 datagrams received out-of-order
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[900] 20.0-21.0 sec 61.3 KBytes 502 Kbits/sec 1113.146 ms -21/ 74 (-28%)
[900] 20.0-21.0 sec 21 datagrams received out-of-order
[900] 21.0-22.0 sec 61.3 KBytes 502 Kbits/sec 77.764 ms 0/ 43 (0%)
[900] 22.0-23.0 sec 57.0 KBytes 467 Kbits/sec 14.260 ms 0/ 40 (0%)
[900] 23.0-24.0 sec 64.2 KBytes 526 Kbits/sec 7.954 ms 0/ 45 (0%)
[900] 24.0-25.0 sec 64.2 KBytes 526 Kbits/sec 7.689 ms 0/ 45 (0%)
[900] 25.0-26.0 sec 59.9 KBytes 491 Kbits/sec 8.179 ms 0/ 42 (0%)
[900] 26.0-27.0 sec 57.0 KBytes 467 Kbits/sec 11.806 ms 0/ 40 (0%)
[900] 27.0-28.0 sec 69.9 KBytes 572 Kbits/sec 7.601 ms 0/ 49 (0%)
[900] 28.0-29.0 sec 65.6 KBytes 537 Kbits/sec 1695.866 ms 65/ 25 (2.6e+002%)
[900] 28.0-29.0 sec 20 datagrams received out-of-order
[900] 29.0-30.0 sec 62.7 KBytes 514 Kbits/sec 1770.001 ms -22/ 22 (-1e+002%)
[900] 29.0-30.0 sec 22 datagrams received out-of-order
[900] 30.0-31.0 sec 48.5 KBytes 397 Kbits/sec 1828.461 ms -17/ 17 (-1e+002%)
[900] 30.0-31.0 sec 17 datagrams received out-of-order
[900] 31.0-32.0 sec 61.3 KBytes 502 Kbits/sec 1839.008 ms -21/ 108 (-19%)
[900] 31.0-32.0 sec 21 datagrams received out-of-order
[900] 0.0-32.4 sec 1.97 MBytes 509 Kbits/sec 968.713 ms 0/ 1414 (0%)
[900] 0.0-32.4 sec 161 datagrams received out-of-order
[900] WARNING: ack of last datagram failed after 10 tries.