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Network and Classroom Management Thread, Network drop outs in Technical; Can you not just web manage into the switch and check the traffic on each port - none of then ...
  1. #16

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    Can you not just web manage into the switch and check the traffic on each port - none of then should max out? Run a wireshark on the network segment and see if anything strange is going on.

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    Even if there's a spike in power it is likely to cause some form of disruption. I would recommend securing a UPS since it compensates for spikes, outages etc - it is quite integral to keeping things going.

    If you have any old UPS units you can get them going by buying the batteries yourself and saving a few bob, otherwise a standard UPS is worth it's value in the long term. (I've even got one for my PC)

  3. #18
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    I think we had found a problem with a switch. We have quickly swapped it out and replaced it and it all seems fine so far today...

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    Quote Originally Posted by newpersn View Post
    I think we had found a problem with a switch. We have quickly swapped it out and replaced it and it all seems fine so far today...
    Oh yeah... it slipped me... my NM mentioned having a similar problem and it was one of the switches.

    Funny thing it didn't give any signs of failure but was the root cause. Replaced and problem solved. I'll ask if any symptoms for sake of curiosity.

  5. Thanks to IT_Ninja from:

    newpersn (18th June 2014)

  6. #20
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    Quote Originally Posted by IT_Ninja View Post
    Oh yeah... it slipped me... my NM mentioned having a similar problem and it was one of the switches.

    Funny thing it didn't give any signs of failure but was the root cause. Replaced and problem solved. I'll ask if any symptoms for sake of curiosity.
    We this switch does a vlan over fibre. But we did get one call this afternoon saying the phones went down but I can't trace that problem. (The guy on our reception isn't the brightness spark in the world)

  7. #21
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    Hate to bring it up....

    But its Back......

    And its seems to be constent aswell.. Just looking though logs of switches now
    Last edited by newpersn; 20th November 2014 at 03:50 PM.

  8. #22

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    Watch out for a failing Fibre Module!
    I had this recently with an Intermittent LAN drop out fortunately it was happening at the edge of the network and only affected a few devices that were not in use regularly.
    We spotted it when the Unifi Server started to report an AP disappearing regularly but the AP of course remained UP and radiating!
    Turned out to be a compatible SFP module and when removed you could smell it had burned out!

    I have also recently had an intermittent link drop elsewhere, which turned out to be the local vermin had taken a liking for a section of fibre cabling!
    Eventually the link died and in replacing the affected fibre drop discovered the well chewed section of fibre of which 2 cores were still intact.

    So it needn't be an overly complicated networking issue, sometimes the physical ones can be as hard to diagnose.

  9. #23

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    You mention in your original post this is effecting all devices on site? The main culprit here sounds like your core switch(es) are at fault if everything is losing connectivity.

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    You could setup smokeping to monitor all switches on a Linux box to monitor drops/packet loss to potentially identify the cause.

    SmokePing - About SmokePing

  11. #25
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    Quote Originally Posted by cscc View Post
    You mention in your original post this is effecting all devices on site? The main culprit here sounds like your core switch(es) are at fault if everything is losing connectivity.
    Looking the core switches. We disable the port its coming in from and it find another port to flood.


    This was taken from an middle switch

    Instance0'sportGigabitEthernet1/0/49wasnotifiedofatopologychange.
    Tones of those messages

  12. #26

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    I would also suggest that you also look into the IP V6 Multicasting issues caused by Intel NICs with bad drivers when in standby as posted in other threads.

    This the sort of thing that can as been suggested, be picked up by Wireshark and can definitely be a potential cause of such issues.

    Dependent on how you have IGMP Snooping setup will depend on how far and wide the impact of one or two bad machines can be.

  13. #27
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    Quote Originally Posted by m25man View Post
    I would also suggest that you also look into the IP V6 Multicasting issues caused by Intel NICs with bad drivers when in standby as posted in other threads.

    This the sort of thing that can as been suggested, be picked up by Wireshark and can definitely be a potential cause of such issues.

    Dependent on how you have IGMP Snooping setup will depend on how far and wide the impact of one or two bad machines can be.
    Im guessing if I update the driver and disable ipv6 might be the couse.

    is there an idiots guide for IGMP?

  14. #28

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    Here is a general overview,
    http://kb.netgear.com/app/answers/de...w-does-it-work

    Check your switch vendors guide for switch specific settings.

  15. Thanks to m25man from:

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