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  • 1.  EX 4200 10G interface speed issue

    Posted 03-06-2019 16:09

    I am running Iperf between 2 servers conneted to EX 4200 via 10G DAC and i am only able to receive speed of upto 4.0Gbps any reason why i am not able to achive near desired speeds? 

    Here's the iperf test result

     

    Server listening on 5201
    -----------------------------------------------------------
    Accepted connection from 10.1.22.22, port 49768
    [ 5] local 10.1.22.21 port 5201 connected to 10.1.22.22 port 49769
    [ ID] Interval Transfer Bandwidth
    [ 5] 0.00-1.00 sec 456 MBytes 3.83 Gbits/sec
    [ 5] 1.00-2.00 sec 459 MBytes 3.85 Gbits/sec
    [ 5] 2.00-3.00 sec 461 MBytes 3.87 Gbits/sec
    [ 5] 3.00-4.00 sec 465 MBytes 3.90 Gbits/sec
    [ 5] 4.00-5.00 sec 462 MBytes 3.87 Gbits/sec
    [ 5] 5.00-6.00 sec 460 MBytes 3.86 Gbits/sec
    [ 5] 6.00-7.00 sec 461 MBytes 3.86 Gbits/sec
    [ 5] 6.00-7.00 sec 461 MBytes 3.86 Gbits/sec
    - - - - - - - - - - - - - - - - - - - - - - - - -
    [ ID] Interval Transfer Bandwidth
    [ 5] 0.00-7.00 sec 0.00 Bytes 0.00 bits/sec sender
    [ 5] 0.00-7.00 sec 3.32 GBytes 4.08 Gbits/sec receiver



  • 2.  RE: EX 4200 10G interface speed issue
    Best Answer

    Posted 03-06-2019 16:36

    I think issue not in ex4200, 
    you should tune some parameters on servers, like tcp window size, tcp window scaling , tcp bif size.

    Also increasing mtu to 9k  on servers and ex4200 also can help you. 

     

    P.S. iperf has some performance issue when run on single process, check cpu at both servers , it is possible that iperf use single core at 100% ...  Try to run multiply iperf instances on both servers,

     



  • 3.  RE: EX 4200 10G interface speed issue

    Posted 03-07-2019 08:47

    Changing the MTU to Jumbo Frames gave the desired result



  • 4.  RE: EX 4200 10G interface speed issue

     
    Posted 03-06-2019 20:13

    Hi nanu4u21,

     

    From the same iperf client you can run multiple parallel streams that gives better results if you're trying to exhaust the link.  For instance, choose more streams (with -P option) and use a higher window size (with -w option).

     

    Example:
    iperf -c 172.16.1.5 -p 9005 -t 60 -P 5 -w 2000

    Note that the default window size is in Bytes, but we can specify K and M for Kilobytes and Megabytes, respectively.

     

    Hope this helps.

     

    Regards,
    -r.

    --------------------------------------------------

    If this solves your problem, please mark this post as "Accepted Solution."
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