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Link Reset issues

  • 1.  Link Reset issues

    Posted 04-05-2017 11:45 AM

    Hello everyone!

    I have a Brocade 300 and it's logging alerts such as Link Reset on Port S0,P0(23) vc_no=0 crd(s)lost=1 auto trigger 

    The portstatsshow 0 shows me:

    tim_txcrd_z 1704079 Time TX Credit Zero (2.5Us ticks)
    tim_txcrd_z_vc 0- 3:    255 0    1703824    0
    tim_txcrd_z_vc 4- 7: 0    0    0    0
    tim_txcrd_z_vc 8-11: 0    0    0    0
    tim_txcrd_z_vc 12-15: 0    0    0    0


    Last night we have a lot of ENC_IN and ENC_OUT errors and performance issues in the environment. These errors were cleared and so far so good. Bottleneckmon was enabled as well and no issues detected.


    Can anyone tell me what this Link Reset on Port... means, please? What should I do to prevent this kind of error?


    Thank you!







  • 2.  Re: Link Reset issues

    Posted 04-05-2017 12:31 PM



    Link Reset on Port means that the port did not receive a R_RDY from the attached device within 2 seconds (E_D_TOV).

    If you are seeing enc_outs and enc_ins on that port that means you have physical layer issues (SFP,cable,patch,etc..) on that port leading to credit loss which forces the switch to issue Link Reset for Credit Recovery.




  • 3.  Re: Link Reset issues

    Posted 04-05-2017 01:12 PM

    Thank you Thomas!
    Also, with the Link Reset error, I can see the following event:

    S0,P0(23): Required buffer unavailable for the port. req_buf:206 port_buf:106 unused_buf:452 est_buf:106.

    I understand that the number of buffers is insufficient. Am I right? Is recommend rasing this number?


  • 4.  Re: Link Reset issues

    Posted 04-06-2017 12:17 AM

    Hi Werneck,


    Adding more buffers will not help for these situations and is not necessary. I see there are a lot of Credits assigned to this port, looks to be a long distance ISL?


    It is possible that you are using all of the Credits on that ASIC that might explain the message. You can check with portbuffershow for available Credits/ASIC.




  • 5.  Re: Link Reset issues

    Posted 11-17-2018 02:39 AM

    recently we have this issue and we just changed the SFP now its working perfectly.


    if in case still the issue is not solved you need to check cable and patch.