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 188.8.131.52]. 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.