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SG300-28P - POE not correctly supported on all ports - possible firmware or hardware issue

Cinemaffect
Level 1
Level 1

So, I spent some time this weekend troubleshooting the issues I've had  with the new SG300-28P switch and POE to many of my devices in the  office.  As a recap, I cannot utilize all of the 24 POE ports on the switch  for POE purposes.  Really only every other port [with a few odd  combinations thrown in between]. In addition, the SG300-28P switch, on occasion, is sending POE to non-POE devices [e.g. my Ruckus Zone Director 1106].

Here are my POE devices [all 802.3 af-compliant]:

  • 3 Ruckus 7982 access points
  • 1 Pakedge access point
  • 2 home-automation controllers
  • 2 Polycom voip phones

I called Cisco support several times in regards to this problem, and they figured it was a hardware issue - a faulty switch.  So, Cisco sent me a replacement SG300-28P, which I  hooked up today.  The exact problem still occurs.  Default configuration  [fresh out of the box].  No way I can land, for example, the 3 Ruckus  7982 AP's on ports 1, 2, and 3 [or ports 1,13, and 2].  I have to put  them on ports 1, 3, and 5 in order for them to power up.  In addition, I  can't plug any other POE devices on the ports either between or below  them.   I had to skip another port bay.  This is very odd behavior!!   Two Cisco SG300-28P's in a row with the same problem.

However, I also had one of the new Cisco SG300-10P switches in my  possession for a recent project of ours.  I decided to hook up the same  POE devices to this switch.  ALL POE devices were recognized and  worked!  No need to skip a port.  And it didn't matter what device was  plugged in first or not.  I am now convinced that it is either a  hardware issue [bad power supply/transformer?] inside all of the  SG300-28P switches, or a firmware issue. 

Both of the SG300-28P switches were running firmware 1.1.2 [the  latest on Cisco's website].  So, I decided to install an older firmware  version on the SG300-28P switch that I'm returning [installed 1.1.1.8].   Here's what I found out.  I could then plug 2 POE devices [e.g. two  Ruckus AP's] in adjacent horizontal ports, but not three in a row.  In  addition, not all adjacent ports.  It's funky. For example, I could plug  an access point in ports 20 and 21, but not in 21 and 22.  No rhyme or  reason in how it worked.  And I still couldn't plug an access point in  adjacent vertical ports [e.g. ports 1 and 13].  BUT...

It's interesting that the same exact switch that would not initially  allow 2 horizontally-adjacent POE ports to be utilized WOULD allow 2  horizontally-adjacent POE ports to be utilized when running a different  firmware version.   It's also interesting to note that when plugged into  a "non-working" POE  port, the SG300-28P would actually make a small whining noise.  Very  subtle noise; I could hear it when approx. 1ft away from the switch.   The noise was not noticeable when ports were skipped [and POE actually  worked].  Therefore, I believe that Cisco has some SG300-28P firmware  bugs [at least in the last two versions of firmware] that is not truly  allowing all 24 ports to utilize POE correctly.  This problem does not  exist with the SG300-10P switch.

I'm really interested to hear what Cisco's reply and findings on this  matter would be.  And would welcome a reply from one of their senior  support team members/managers who could actually experiment with this,  too.   In addition, I'd like to know when they think a solution could be  created if it's firmware-related.  If hardware-related, I don't think  I'll be recommending any 28P switches in our projects.  Perhaps just the  regular SG300-28 with a separate SG300-10P.  It's a shame because the  SG300-28P is more of a bargain when compared to the two separate  components.

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