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SG200-50 Do I have a loop? I think I have tried everything.


I have 4 of these switches and all lights are blinking extremely fast and in sync, even on the server nic cards. I do not have access to SSH nor the Console (UGH!). I have unplugged all 4 at the same time and plugged just one back in and it did the same thing. So I uplugged it again and plugged one other in, trying to isolate a physical loop. In doing this troubleshooting, I found that each switch does the same thing whether any other switch is plugged in. This does not make sense to me. How could each one do it if no other switches are plugged in. I ran wireshark and I do see some a couple TCP Spurious Transmissions and TCP Dup ACK. There is some broadcasts but does not look out of the ordinary as I do have a WINS server and couple xp embedded boxes that have to stay. So I do not really see a broadcast or multicast storm. I have gone around the building and did find a couple 4 port switches plugged in but verified they were not causing the loop. 


I have looked in settings of the switch and my new dell laptop and our hp conference room laptop show up in the LLDP table with a TTL of around 3400, while all the uplink ports are around 90. 


The only other item that is plugged into a switch is a cisco wireless controller for our two APs, which are cisco as well.


That is all i can think of to do. Anyone have any ideas??


Thank you in Advance!!!!

6 Replies 6

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what is the Logs in the switch shows ( any obnormal ?)


what happends if you remove all the device from switch ( i know in live environment not possible, but for long solution business should give down time to resolve the issue) ?


what is the firmware running, is this new deployment, or running one having issue..when was the issue started ?


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Firmware Version:
  Firmware MD5 Checksum: 
PID VID: Boot Version:
  Boot MD5 Checksum: 
  Language Version:
  Language MD5 Checksum:N/A


Logs are normal as far as I can tell, below is a clip:

21474834282011-Nov-24 14:25:20Warning%STP-W-PORTSTATUS: gi31: STP status Forwarding      
21474834292011-Nov-24 14:25:16Informational%LINK-I-Up:  gi31      
21474834302011-Nov-24 14:23:47Warning%LINK-W-Down:  gi31      
21474834312011-Nov-24 10:15:01Warning%STP-W-PORTSTATUS: gi5: STP status Forwarding, aggregated (1)      
21474834322011-Nov-24 10:14:56Informational%LINK-I-Up:  gi5, aggregated (1)      
21474834332011-Nov-24 10:14:53Warning%LINK-W-Down:  gi5, aggregated (1)      
21474834342011-Nov-24 10:12:03Warning%STP-W-PORTSTATUS: gi5: STP status Forwarding      
21474834352011-Nov-24 10:11:58Informational%LINK-I-Up:  gi5      
21474834362011-Nov-24 10:11:53Warning

%LINK-W-Down:  gi5      


I have not removed the devices from the switch except for one. I am planning on doing that this weekend. It is not a new deployment. I inherited this network approximately 2 months ago and I noticed it on my first day.


Also everything is configured with defaults. No VLANs, nothing....



Do you need any asistance or is this fixed ?


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