Wireless Networks Thread, Ruckus AP zf7982 in Technical; We have a number of these APs dotted around the school currently and all working from Mains power. From September ...
24th April 2014, 10:54 AM #1
Ruckus AP zf7982
We have a number of these APs dotted around the school currently and all working from Mains power. From September we will be having more installed in a new additional school block and plan to use these on POE via a POE capable netgear switch.
Can people let me know if they have had any issues with these APs running on POE.
24th April 2014, 11:34 AM #2
We don't use that exact model (all ours are 7363's) but they were designed to be used over PoE, so I can't imagine a problem. I'd suggest that the vast majority of these are running over PoE and your current setup is in the minority.
Just ensure your new switch has enough power for the amount of APs you are connecting - although the ruckus APs are fairly lean on power. Looking at mine now, they pull between 3.9 and 4.5 watts each.
Thanks to IrritableTech from:
mdrabble (24th April 2014)
24th April 2014, 11:40 AM #3
Make sure you have the correct PoE standard for them.
Looking at that model, it works with 802.3af and 802.3at, as its max wattage is 13W. Which means, I believe, that all Netgear's 802.3aX switches will work fine. Just best to double check.
Thanks to localzuk from:
mdrabble (24th April 2014)
24th April 2014, 11:51 AM #4
@IrritableTech what switches do you currently use with your APs?
24th April 2014, 11:52 AM #5
With the 7982 it advertises itself as a Class 4 PoE device (as do other enterprise class 3-stream APs), which is compatible with 802.3af and 802.3at switches. 802.3af switches re-classify a device with this behavior as 802.3af Class 0 (15.4W), and the vast majority of 802.3at switches classify it as 802.3at Type 1 (15.4W). This implementation is intentional as it maintains compatibility with both 802.3af and 802.3at switches, and allows the 7982 to support full 802.3at power (>15.4W with a future firmware upgrade to support LLDP, if required).
Some 802.3at switches will reserve 30W for a Class 4 device by default, and will only power as many devices as their power budget divided by 30W will allow. If a 7982 is plugged in to one of these switches which has already allocated its power budget, that 7982 may be denied power, or another device may be powered down to accommodate the new AP.
When ZoneFlex 7982 AP’s are plugged in to adjacent ports on certain PoE switch models, some AP’s fail to power up. Ruckus has investigated the issue in depth and believes this not to be a 7982 product problem, but rather a common design flaw found among several models of PoE switch.
A common design practice in multiport PoE switches is to use components which group some of the Ethernet circuitry for multiple ports together – e.g. 1 component serves 2 or 4 adjacent ports. If these components are not configured properly, they can introduce “illegal” circuit paths (DC current paths) from one port to another, which can be problematic if there is an AP on both ports since it interferes with APs’ PoE circuits. Ruckus has found this to be a common cause of ZoneFlex 7982 failures on several different PoE switches.
Some devices are more sensitive than others to this switch design. Ruckus has reproduced the problem with switches known to have this design issue with Ruckus and non-Ruckus APs. The problem has also been reproduced on both 802.3af and 802.3at switches which exhibit the issue. The problem does not exist with switches which are properly DC-isolated.
Ruckus have a list of tested switches where they have found concurrent ports to support mutliple 7982's but currently this list does not include any Netgear switches. From my experience Netgear can be a touch sneaky with mutli port PoE Power budget and the key thing to ascertain is that there is sufficient PoE budget to provide Power for the total number of AP's, then look if possible at spreading the AP's across non-concurrent ports.
If you want to drop me a PM with the Netgear models you have I can certainly have a look into it a bit further for you.
Thanks to CPLTD from:
mdrabble (24th April 2014)
24th April 2014, 11:53 AM #6
Most of our APs run from HP E2900AL's but some run from our 5412ZL as well.
Looks like there have been issues though... thanks @CPLTD
Last edited by IrritableTech; 24th April 2014 at 11:55 AM.
24th April 2014, 12:09 PM #7
@CPLTD many thank for that
Not sure on the model of Netgear switch as yet.
We are having a new 6th form block built and as part of the tender we having that model AP installed so it integrated into our existing ruckus system.
We originally asked the builders to put a single power socket next to the data sockets for the APs incase there were issues and were having second thoughts about needed power sockets.
I think we will stick with the additional power sockets just incase we do have POE issues.
Thanks for all the replies :-)
24th April 2014, 12:31 PM #8
It's something we've found with a few vendors higher spec AP's and several switch manufacturers, as you can imagine though the switch vendors tend to be loathe to concede that their internal wiring might be slightly dubious!
Other alternative is to use Single or multiport 10/100/1000 PoE injectors, not quite as "pretty" a solution within the cab but works well and removes the need for PoE capable switches, which can be useful to save some £ when you only plan on using one or two ports PoE.
29th April 2014, 02:40 PM #9
We're hoping to get some 7372's and some 7982's in the not to distant future (assuming the money appears from down the back of the sofa) and intend to run them off of Netgear GS728TP and GS516TP.
Anyone had any power issues?
29th April 2014, 03:35 PM #10
Yes, as above make sure that you have a switch that can handle the total powerload AND can do POE+ which allows for POE and a gigabit over the 4 pairs...
depending on how many APs you have I'd recommend this switch
HP 1910-8G-POE+ (180W) SWITCH | Ebuyer.com
I have the 65w version it has all the toys and has a 9th sfp port for fiber if you need it.
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