ExtremeSwitching (EXOS)

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Tips to find root cause of problem

  • 1.  Tips to find root cause of problem

    Posted 04-04-2018 18:26
    latency of some computer in one specific vlan, Not all of the computers are affected, but it is increasing... checking traffic on ports, no messages on Core. If I move the pc to a different vlan the problem is solved for that computer, but still happening on the vlan. Please help


  • 2.  RE: Tips to find root cause of problem

    Posted 04-04-2018 19:35
    Have you checked for:
    - port error counters
    - client side error counters
    - counters in general

    What does a tcpdump from a client show?
    How are you measuring the latency and how much of a change are you measuring?


  • 3.  RE: Tips to find root cause of problem

    Posted 04-04-2018 19:57
    Yes... I check.. but nothing.. on the counters all normal, but a did a sh fdb port on all the ports in the affected vlan... and found a switch connected, as soon I disable the port the other pc's normalize... now we need to check if it is the switch or a pc connected to it generating the traffic...

    Thanks



  • 4.  RE: Tips to find root cause of problem

    Posted 04-04-2018 20:27
    🙂 I suspect your network was looped with that other switch and you were encountering a broadcast storm. This would be apparent in a tcpdump from the client; you'll see the same broadcast packet appear in the dump multiple times. Have you enabled erp on the switch? I think it's erp; erp will automatically shutdown ports when it detects a loop.


  • 5.  RE: Tips to find root cause of problem

    Posted 04-04-2018 20:27