PowerConnect 5548 stack - one switch not working

Question

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

jaybietz · Answer

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

syuroff · Answer

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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