I have setup like below.

   Switch1-------------------- Switch2
    |    |                      |    |
    |    |                      |    |
    |    |                      |    |
   PC1   PC2                   PC3   PC4

I have a video traffic is flowing between PC1 and PC4. I have configured PC2 as iperf server. ( iperf -s ) and PC3 as client . (iperf -c 10.10.10.2 -P 20 -t 10000) where 10.10.10.2 is PC2 IP.

now I am seeing most of the traffic in a link (switch1---switch2) is iperf. (TCP). I have observed from the logs that 1 out of 300 packet is UDP. Still I am not seeing any difference in the quality of video streaming in PC4. It looks similar compared to the case with no iperf.

I am checking QOS, I have tried many options with iperf, couldnt succeed. I want to diminish the quality of video streaming in PC4. Could you please tell me what options can be used along with iperf to do it.

Bandwidth between Switch1---switch2 is 1Gbits/sec.

Thanks in advance