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jaybietz

3 Posts

19366

July 10th, 2015 11:00

PowerConnect 5548 stack - one switch not working

I have a stack of 5 5548 switches using HDMI cables with a cable from # 5 to #1 to complete the loop.

All switches have the firmware 4.1.0.16

I discovered using LanSpeed Test on a PC - that Switch #3 causes dramatic differences in upload vs download thruput. ie Writing a 20M file to a server is 16 Mbps and reading the
20M file is 354 Mbps...

When the same testing software was run on the same computer to the same network share - but on switches 1 2 4 5 - these results are for a 20 Mbps file write 324 Mbps and read
360Mpbs.

I would like to keep using this switch but it is out of warrenty and support.

Question: I see that the HDMI left LED on all switches are solid green. The right LED are flickering on switch 1 2 & 5 but on 3 and 4 only 1 of the 2 HDMI ports have the right
LED flickering. Should all the HDMI right LEDs' be flashing? What is the Normal HDMI LED condition with this wiring configuration?

Switch three is setup more or less just like the other switches - looking at the log files nothing caught my eye = error rates were very low to non existent.

Resetting the #3 switch via the web app - last night made the thruput results even worse then before the reset.

I've moved all the active ports from #3 switch to the other switches and retesting on #3 switch - same slow thruput and the other switches have the same good thruput so I don't
think the issue was caused by an network device.

Ideas?

TIA

Anonymous

5 Practitioner

 • 

274.2K Posts

July 10th, 2015 14:00

the left light is the speed/link light and a solid green light indicates that the link to another switch has been made. The right light is the ACT light. When it is flashing green it indicates that the port is transmitting/receiving. When it is off it means the port is not transmitting/receiving.

Do you have another cable you can use in place of the cable that shows no ACT lights? Or perhaps swap the cable with another cable in the stack. This would let you see if the no ACT light follows the cable or stays with the switch. This would be a good first troubleshooting step that would not have much impact on the stack.

Once the swap is done note any LED changes and speed changes, if any.

jaybietz

3 Posts

July 12th, 2015 14:00

Daniel-C

Thanks for the reply.  

I changed the wire from #2 to #3 and now the speed is back... All HDMI wires are from Dell.

I also notice that with the cable from the #5 unit to #1 unit in place - one of the links does NOT show the activity lights on either end - I'm thinking this is normal but can't find supporting online documentation either way.

Thanks for the assistance. I actually think the switch is working as expected...

Jay

Anonymous

5 Practitioner

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274.2K Posts

July 14th, 2015 06:00

Glad to hear it! Thanks for the update.

syuroff

1 Rookie

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21 Posts

March 19th, 2019 11:00

Sorry for bumping a very old thread, but I'm here because I'm fighting the same problem. I wanted to throw in that expected behavior is for the ACT light to blink on all active links, indicating both backplanes are being used actively. When one doesn't, something is wrong. I think jaybietz might have relocated a problem. I too have a stack where 2-3 link is not used unless 1-2 or 3-4 links are disturbed (then the 2-3 ACT DOES light), and see the same problem with asymmetric speeds. All I can add is that replacing the 2-3 HDMI with a Dell part didn't fix the stack, nor did a replacement switch adopted into the stack and provisioned first in replacement for unit #2, then for 3.

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