PoE Switches

bodhiguy · Sun Jan 15, 2006 1:58 am

Forum. I'm wondering if anyone is using PoE switches for powering RB 532s? I noticed the IEEE language states no more than 12.5 watts of draw and if my calculations are correct, we need 15.8 watts to power the RB 532 ?

Thanx in advance for any advice.

BrianHiggins · Mon Jan 16, 2006 6:15 am

I've tried a few, unsuccesfully.

neither the Netgear FS116P or the FS726TP PoE switchs will work with the RB532. I don't know why, netgear told me that they would ship me a "free" FSM7326P to try, but I would have to purchase it if the switch powered worked and my devices (the MSRP is $1750) so I declined the offer.

has anyone else had any luck with powering the RB532's with a PoE switch? I want to clean up my wireing at the base of my towers and get rid of all those PoE injectors...

bodhiguy · Mon Jan 16, 2006 7:44 pm

Does anyone know what the power draw is on the 532 boards via the PoE port? We know the PoE injectors are 48 volt, but does this mean that we must use 48volt PoEs, if not, we may be able to get a switch that will put out enough power to light up these boards and clean things up at our main tower and microPoP locations.

Thanx all.

Wyoming · Wed Jan 18, 2006 2:37 am

There are jumpers on the RB that allow you to select what voltage of POE you use. JP3 & 4 allow you to select between different voltages.

From the Documentation
IEEE802.3af Power over Ethernet: 12V or 48V DC
Power jack/header 6..24V or 25..56V DC jumper selectable

There is some fine print on the edge of the RB that tells you what position of the jumpers is what voltage.

wildbill442 · Wed Jan 18, 2006 5:30 pm

The PoE injectors that ship with the RB500's output 48VDC @ 0.35amps, which would require 16.8 Watts..

So is there a PoE switch that can output ~17 watts per port?

aviper · Wed Jan 18, 2006 8:57 pm

According to the standard 802.3af the maximal power that can be transmitted over the Ethernet is 15,4W.

Soo sooner or later we will see such devices

.

arve · Thu Jan 19, 2006 6:01 pm

Have any of you seen PoE switches with support for battery power supply?

BrianHiggins · Sun Jan 22, 2006 1:05 am

does anyone know of ANY PoE switches that work with the routerboard's?

jp · Mon Jan 23, 2006 2:31 am

These are my power consumption measurements.

rb532+cm9+sr5
cm9 on, sr5 on
12vdc
.32 amp cm9 bandwidth test 37mbps
.24-.29 amp cp9 regular ping
.22-.29 amp cm9 all idle
.22 sr5 disabled

Based on this, it looks like a MT RB532 would not use much more than 4 watts of actual power.

stephenpatrick · Mon Jan 23, 2006 10:59 am

AFAIK

POE switches put the power on the data pairs
POE injectors put the power on the spare pairs (midspan)

Have not tested RB's with POE switches, can anyone confirm whether they can run with power on the data pairs?

Regards

CableFree Solutions

andreacoppini · Tue Jan 31, 2006 3:38 pm

AFAIK

POE switches put the power on the data pairs
POE injectors put the power on the spare pairs (midspan)

AFAIK, the 802.3af standard provides for both power-on-data-pair AND power-on-spare-pair, so a true 802.3af powering device (wether a switch or a mid-span injector) should be able to support both.

Again AFAIK, MikroTik RB's only support the power-on-spare-pair type.

freebird · Tue Jan 31, 2006 10:54 pm

There have been a thread in the routerboard forum:

http://forum.routerboard.com/viewtopic. ... hlight=poe

It seems that the RB532 are not 802.3af conform. They seem to only support powering on the spare-pair (4-5(+) and 7-8(-)) ...
There are several devices on the market that pretend to support 802.3af and many of them only support one of the three methods.

Up to now we only found Lancom Accesspoints that support all three powering methods,

Spare-Pair
Phantom/Data-Pair Straight cable
Phantom/Data-Pair Cross-over cable

Hope every vendor would state which methods the device supports.

I hope Mikrotik will clear this up and remove the "802.3af compatible" feature, or support it fully standard conform.

seandsl
--

Wed Feb 01, 2006 10:30 am

We do not support power over datalines. New products will. We will add this note to our specs.

_andy_ · Thu Jun 01, 2006 12:31 pm

Hello,

Hi try to connect rb522 to a PoE switch shuch as Netgear 108PEU and not work. If conmute the data cables 1&2 to 4&5 and 3&6 to 7&8 the device is power up and work. The power comsuption is under 15,5w.

Hi try too whith a linksys srw224p and not work.

Thu Jun 01, 2006 12:32 pm

read the post above yours

jo2jo · Thu Jun 01, 2006 1:27 pm

i see this topic is pretty much closed but i wanted to add this;

my dell 3424p poe swtich will provide upto 15.7watts per port...its a great sw, but as described does not power RB's or WRAP boards....since i have 15 wrap AP's at this install this was a problem. so Pacific wireless makes these POE splitters that work great....gives u data on cat5 and a seperate 12v @ 1A dc plug! i'll test it on a RB tomorrow but i can say that it powers my WRAP boards great! and each of them draw 5-8watts as told by the switch.

EACH of these wrap's is running 2 400mw Radio's so i think the 15 watt RB + Radio usage projections are off....

overall you CANT beat the poe switch setup on AP's....i can reboot each AP via the switch....AND i have this 1 SW plugged into a UPS and get around 2 hours backup time!!! on 15 APs with activity! pretty cool.

joe