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trunks do not distribute traffic evenly

  • 1.  trunks do not distribute traffic evenly

    Posted 02-09-2019 02:59 AM
      |   view attached

    Hello

    Environment:
    2 DCX 8510 connected using ICL ports.
    5 VF with trunks enabled and working.

     

    DCX11_SVC_IC:FID107:admin> trunkshow
    1:388->388 10:00:c4:f5:7c:aa:fb:63 27 deskew 15 MASTER
    384->384 10:00:c4:f5:7c:aa:fb:63 27 deskew 16

    2:420->420 10:00:c4:f5:7c:aa:fb:63 27 deskew 15 MASTER
    416->416 10:00:c4:f5:7c:aa:fb:63 27 deskew 15

    DCX11_SVC_IC:FID107:admin> islshow
    1:388->388 10:00:c4:f5:7c:aa:fb:63 27 DCX21_SVC_IC sp: 16.000G bw: 32.000G TRUNK QOS CR_RECOV FEC
    2:420->420 10:00:c4:f5:7c:aa:fb:63 27 DCX21_SVC_IC sp: 16.000G bw: 32.000G TRUNK QOS CR_RECOV FEC


    The thing is that Performance in interswitch connections (ILS) are evenly distributed
    but NOT among the port belonging a trunk
    This happens in every trunk of every VF ..... with trunk comprised of 2 up to 4 ports .....
    I have appended an example of that behaviour

    As far as I know trunking meaning is just to spread all traffic evenly with a better use of th vc channels ... but we got  here is just the opposite

     

    Anyone can explain me that?
    In the other hand .... the deskew value (expresed in nanosecs/10) can vary from 15 to 18 in some isls. Is that relevant??

    thanks in advance and best regards, Alberto

     


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    Attachment(s)

    docx
    TrunksPerf.docx   509K 1 version


  • 2.  Re: trunks does not distribute traffic evenly

    Posted 02-09-2019 01:57 PM

    Since 4Gb (10+ years ago) trunks do not distribute traffic evenly between the individual trunk members.


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  • 3.  Re: trunks does not distribute traffic evenly

    Posted 02-11-2019 12:27 AM
    Thanks Alexey,
    I'm getting %portused alarms and discarded frames on these ports
    If I cannot use evenly the ports in a trunk, then what is the fucntion of trunking? (besides encapsulating isls into one)

    Thanks in advance

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  • 4.  Re: trunks does not distribute traffic evenly

    Posted 02-11-2019 02:50 AM

    Trunking algorithm is proprietary. Basically, the links inside the trunk are numbered at the moment of the trunk creation, and then the load is distributed based on some rules. The less the number of a link, the more the load. %portused alarms are just alarms, and they are adjustable. Discarded frames is something very different. It might be that you have a slow drain device attached somewhere up the link. Do you see any other symptoms, e.g. CRC errors?


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  • 5.  Re: trunks does not distribute traffic evenly