wrong parameters?
Hi all,
I was trying to send traffic from client -> server using the following specification:
- constant streaming UDP traffic
- payload size 160 bytes
- sending 50 packets per seconds
- let it run for 1 hour
- format output in kbps
- display report every 1 sec interval
- iperf v 1.7, running on Windows 2000 box
- client and server is separated by T1 running PPP
On the server side, I use the following parameters:
iperf -s -u -f k -i 1
On the client side:
iperf -c server_name -u -l 160 -n 50 -t 3600 -f k -i 1
I got the following results from the server:
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[900] 0.0- 1.0 sec 127 KBytes 1043 Kbits/sec 2.438 ms 0/ 815 (0%)
[900] 1.0- 2.0 sec 128 KBytes 1052 Kbits/sec 2.444 ms 0/ 822 (0%)
[900] 2.0- 3.0 sec 128 KBytes 1052 Kbits/sec 2.353 ms 0/ 822 (0%)
My problem:
1) iperf should only send 50 packets per second, but instead it sent around 800 packets per second
2) The bandwidth should be around 77kbps. But the reported bandwidth is 1043 Kbits/sec.
My calculation is as follows:
L2 header (PPP) : 6 bytes
IP header : 20 bytes
UDP header : 8 bytes
Payload size :160 bytes
TOTAL packet size:194 bytes
50 packets per seconds * 194 bytes = 9700 bytes
To put in in kbps = 9700 bytes * 8 = 77,600 bps (77kbps)
So, I wonder whether my logic is correct? or the parameters used was wrong? or iperf is not the right tool to achieve this?
Any input will be appreciated, and thanks in advance for any help on this!
Regards,
Aldo