SG200-8 port 1 disabled

[SimonAshwo]

I have an SG-200-8 which connects to a stacked pair of SG500-28P switches. It is powered by PoE from the SG500. From the SG500 the port appears Up, but at the the SG200 it is disabled and nothing I do re-enables it. I know the cable is good because I had a previous netgear switch hanging off it and working, also the power gets through.

I can only connect to the switch if I disable wifi and plugin a manually configured PC - DHCP doesn't get through to it from the SG500 end.

I have tried a second SG200 same problem. Have disabled RSTP/ STP thinking it might to relate to the fact that a PC connected to the switch also had a wifi connection to the same LAN, but. Don't know where to go next. looks like a bug?

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[Tom Watts]

Hi Simon, the port may be suspended on the Sg500. Can you check the  port management -> port setting , choose the port, edit it and see if there is the option to reactivate the suspended port? (from cli it is set interface active x/x/x)

-Tom
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[SimonAshwo]

Hi Tom

Sorry to be slow. The problem is this. When connected using PoE to one of my stacked Cisco SG500-28 it simply will not establish a net connection on port 1, the PoE port. It boots but the SG200 only illuminates system not the port 1 light, and diagnostics on the SG500 say the link is down. It seems to work via the second SG500-28, and also if I plug it into power.... But I was hoping to use it via PoE!

The problem isn't excessive draw from PoE only devices draw on this all Cisco wireless adaptors with a draw of 5000.

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[Tom Watts]

Hi Simon, quite honestly this is not supported and should not be practiced. In the most technical point of view, it is actually a software exploit to try to use in this manner. The switch is a PSE (power sourcing equipment) not a PD (powered device). It is meant to supply power to a device, not receive power to operate.

The exploit I mentioned is because these units are designed to work with legacy POE standards. The switches should always be powered by AC connection. It is an exploitation in software because it is a false signature detection in an effort to power a PSE which is being sensed as a PD.

I would encourage you to use the AC power and avoid this practice as configuration scenarios and the unexpected behavior cannot be supported.

-Tom
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[kmccourt]

The SG200-08 is a PD device and supports being powered over port 1.

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[Tom Watts]

Hi Km, do you have Cisco documentation showing the 8 port model is a PD and not a PSE? Please share.

-Tom
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[kmccourt]

Apart from having several in my office working in such a manner, please see this post from early last year where I raised this question:

https://supportforums.cisco.com/message/3525165

Note that the SG200-08 has the PD option whereas the SG200-08P does not but has 4 PoE ports.