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tech012013
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Dell DGS-1248T and other switches having random ports showing "unidentified network"? Brown outs..

I have a series of switches installed, with fiber interconnects.

At the top most switch is this switch: HP V1810-48G (a layer 2 switch that doesnt support spanning tree although the spec seemed to say it did, but does support storm control)..

Then a newer Dlink/Dell DGS-1248T also a layer2 switch (supports spanning tree)

Then there are about 4 other DGS-12848T's which are pretty old, dating back to 2005-2008. The lowest of these from top to bottom on the rack all goto servers, though there are a few servers on the topmost one.

Randomly over the last year or so I have had ports that wont get an ip address despite lighting up on the other end of the switch. On the windows side, they show "unidentified network".. if i move the port to another one of the switches it works.

For awhile I had assumed it was just the "bad/older" switches with issues.. but recently almost half of all ports went dead on one switch, this time the newer HP switch.. I lost DHCP, many servers went to unidentified network as well as workstations.

So i'm at a loss as to whats going on here. I'm not sure if maybe this is spanning tree related, or lack of spanning tree ability on the HP at least.

My plan was to add another switch and try to isolate these one by one.. in this case adding a layer3 switch like the Cisco SG 300-52

Seems often, ill have one port working fine on the SAME switch, then a few down from that port on same switch will be ones that report unidentified network etc..

We run a domain, the windows 2012 domain controller runs DHCP, DNS.. the servers and hardware are all static ip's (even some of the physical hardware with static ip addresses seemed to be affected as well)..

We have about 40 workstations, three hyperv servers and many VMs.. the workstations are dynamic.

But again, for some reason this "glitch" affects even static ip machines/hardware.. i guess it wasnt just DHCP.. For machines where i can view the network status this is where i see "unidentified network".. so the top HP (newest switch) seemed to have the most affected. Moving a plug from there to a lower tier one fixed the issue for now.


Going from top down 

POE switches for our IP Phones (4 of them)
Then the workstation / server switches

HP
Dlink
Dlink
Dlink
Dlink

All interconnected with fiber connects.

I dont think i have spanning tree enabled on any of the dlinks (which do support it).. technically the HP should too, but i cant find the area in the web configuration to set it, never could.


Any thoughts as to what could be going on or how to troubleshoot this?

Thanks in advance

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