Tips to find root cause of problem

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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
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Karina Del Moral

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Posted 3 months ago

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Robert Cummins

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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? 
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Karina Del Moral

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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
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Robert Cummins

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:-)  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.  
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Dorian Perry, Employee

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