Does Forti AP U431F Support 4x4 MU-MIMO

[LiaoChiaNan]

HI~ According to https://www.fortinet.com/content/dam/fortinet/assets/data-sheets/fortiap-u-series.pdf  FortiAP U431F FAP-U431F Indoor Wireless Universal AP - Tri radio (2x 802.11 a/b/g/n/ac/ax, 4x4 MIMO and 1x 802.11 a/b/g/n/ac Wave 2, 2x2 MU-MIMO)

Does that means FAP-U431F only support 2x2 MU-MIMO at Radio3 ? Radio 1 and Radio 2 only support SU-MIMO ? Thank you~

[Toshi_Esumi]

My understanding based on the  spec sheet is the same for your first question. But I don't understand your second question. MU-MIMO or SU-MIMO is generaly only on AP side. Clients wouldn't be affected by that. Or are you asking if it supports clients with 802.11n capability? Then of course yes. That's why "n" is listed in.

[LiaoChiaNan]

Hi  Toshi Esumi :

Refer to the spec

FortiAP U431F FAP-U431F Indoor Wireless Universal AP - Tri radio (2x 802.11 a/b/g/n/ac/ax, 4x4 MIMO and 1x 802.11 a/b/g/n/ac Wave 2, 2x2 MU-MIMO)

FAP-U431F has 3 radio.

radio1 and radio2

2x 802.11 a/b/g/n/ac/ax, 4x4 MIMO

radio3

1x 802.11 a/b/g/n/ac Wave 2, 2x2 MU-MIMO 

What i want to ask is :

radio1 and radio2

2x 802.11 a/b/g/n/ac/ax, 4x4 MIMO  

that means 4x4 MU-MIMO or 4x4 SU-MIMO ?

thank you~

[Toshi_Esumi]

The 802.11ax standard includes two-way or downlink+uplink MU-MIMO while 802.11ac does only downlink MU-MIMO. SU-MIMO is before Wave2, or 802.11n (Wi-Fi 4) and before. 

[LiaoChiaNan]

Thank you  Toshi Esumi ,

so , when i config   radio1 and radio2   as 802.11ax mode support both download/upload 4x4 MU-MIMO  and  802.11ac mode support download 4x4 MU-MIMO ,depends on client device,

is that right?

Another question about the  Release Notes.

FAP-U431F and FAP-U433F are compatible with IEEE 802.3af PoE input.

[ul]With a single 802.3af PoE on either the LAN1 or LAN2 port, FAP-U431F and FAP-U433F limit the 1st and 2nd radios to operate on 2 spatial streams only, and disable the 3rd radio.With dual 802.3af PoEs on both LAN1 and LAN2 ports, FAP-U431F and FAP-U433F support the same full set of functionalities as powered by IEEE 802.3at PoE.[/ul]

That  means with a single 802.3af poe , U431f can use only 2x2 mimo not 4x4 mimo?

Thank you.

[Toshi_Esumi]

MU-MIMO itself is mostly for AP side that handles multiple client devices (transmit and receive) at the same time. Of course, the client device needs to support ac or ax though. I'm thinking buying a new laptop that supports ax, which might be less expensive than getting a smartphone that supports ax before getting an AP supporting ax.

[LiaoChiaNan]

 In my view, MU-MIMO  needs both AP side and client side support.  Reference  page 7 of 17

More than one MU-MIMO client is necessary. At least two clients must support MU-MIMO and have the ability. to report CSI to allow grouping them together for spatial diversity. A network with only one MU-MIMO client does not benefit from using an MU-MIMO AP. For example ,my laptop gets Intel AC8260 Chipset build in, of course my laptop support 802.11ac.

But  Intel AC8260 Chipset  does not support MU-MIMO.

I think that means even using an MU-MIMO AP, the MU-MIMO function does not  work.

I also have many usb wifi adapters  support 802.11ac  2x2 MU-MIMO for my desktop computer user. 

EW-7822ULC 

That's why i want to figure out FAP-U431F's radio1 and radio2 supports 802.11ac 4x4 MU-MIMO or not .

Thank you.

[James_G]

LiaoChiaNan wrote:

Another question about the  Release Notes.

FAP-U431F and FAP-U433F are compatible with IEEE 802.3af PoE input.

With a single 802.3af PoE on either the LAN1 or LAN2 port, FAP-U431F and FAP-U433F limit the 1st and 2nd radios to operate on 2 spatial streams only, and disable the 3rd radio.With dual 802.3af PoEs on both LAN1 and LAN2 ports, FAP-U431F and FAP-U433F support the same full set of functionalities as powered by IEEE 802.3at PoE.

That  means with a single 802.3af poe , U431f can use only 2x2 mimo not 4x4 mimo?

Thank you.

I think if you are planning to roll these out, a POE+ (802.3at) switch should be considered a pre-req. Then, not a problem.

[LiaoChiaNan]

Hi James_G

Recently i have 45 U431F to install.

If i need all these 45 U431F full function at POE+ (802.3at),

that means i need 45 * 30W = 1350W.

Unfortunately most of my POE switch doesn't have enough POE budget.

Like FORTISWITCH 124E-POE, the poe budget is 185W.

And the other poe devices like ip-phone,ip-cam also need poe.

That's  indeed a problem.

[James_G]

POE+ injector if nothing else works

PS - just talking delivery of some Netgear switches with 700W POE+ budget across 48 ports, that budget on the fortiswitch seems a little limiting :(