SWY's technical notes

Relevant mostly to OS X admins

PoE: sometimes yes, sometimes no.

After the deployment of my stack of 3 Dell 5548P switches recently, and the purchase of 4 Ruckus 7372 APs (and the ZoneDirector controller), I started working on deploying the Ruckus APs.  Naturally, with a back end of PoE switches, that’s the desired route to power them.  However, as I started placing them, I found that sometimes the APs would come up as expected, and in other ports they wouldn’t.

I audited the switch configuration, looking for any form of “no power for you!” defined on the trouble ports: no, power is available to all. I took 2 APs directly to the switches themselves, and plugged into ports, to bypass any potential issues with the building cabling. Here I found ports where the APs would come up, and other ports where they wouldn’t, with no visible pattern of success vs fail emerging.

In my troubleshooting research, I found a thread in a Cisco support forum documenting similar behavior, where Ruckus APs can’t always be powered via Ethernet as expected.  I asked @DellCaresPro on twitter if they were familiar with any issues between their switches and Ruckus gear, but they replied that they hadn’t documented any such issues.  Dell’s advice was to upgrade the switch firmware, which led to it’s own adventures in setting up a TFTP server, which I may document next.

This entry doesn’t contain a solution to the problem yet- I’m throwing it out there so that perhaps if someone Googles the right terms, they might learn they’re not alone.  Once I can do the firmware upgrade, I’ll see if I can get the expected behavior of plug into any port, get power.

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One response to “PoE: sometimes yes, sometimes no.

  1. Mush June 29, 2014 at 10:02 am

    Thanks for this post. A firmware upgrade seemed to help (so far).

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