Hi,
Short answers:
Yes, C9130, C9136 and see below the explanation for 8x8:8.
Most probably you don’t need one.
If you do not go for an 8x8 you do not need UPoE. PoE+ (30w) will be enough.
Cisco has some multi gig 60W UPoE (Cisco Business 350 Series Managed Switches; there might be other, but I looked only in the SMB area)
If I were you, I would go maximum for a 4x4:4 Wi-Fi 6E APs. For a dense environment with high throughput needs I would go for more 2x2:2 Wi-Fi 6E APs. For the time being you will get more total throughput for the current devices, and you will do much better when most of the devices will be wifi6E capable (the 6 Ghz channels will be a life changer in all the environments but especially in the dense ones). I think of home, office, classroom scenarios with APs with internal antennas. Stadiums and big concert halls are different stories.
Anyway, there are lots of things to consider to have the best setup for your environment, so I recommend to have a look at this page https://www.cisco.com/c/en/us/td/docs/wireless/access_point/feature-matrix/ap-feature-matrix.html?dtid=osscdc000283
Keep in mind that all APs have a different number of antenna and streams for each radio and normally they have 2 radios. One using the 2.4 band and another one using the 5Gz band. Wi-Fi 6E devices have a 3rd radio that is using the new 6Ghz band.
The Cisco new C9136 has 3 radios; a 4x4:4 on 2.4 Ghz, 8x8:8 on 5Ghz, 4x4:4 on 6Ghz
Now the explanation for my advice.
As I own and tested a Cisco 8x8:8 device (C9130axi) I will share with you my learning and real-life findings hoping that it will help you and others make the best use of your network budget and maximize the user experience as 8x8:8 are very expensive devices that not necessarily contribute to the user experience (and this is what matters to me). I will also consider that all devices (APs, PCs, mobile devices work as specified and there are no bugs. Please see the things I struggle with in the thread I opened. https://community.cisco.com/t5/wireless/catalyst-9130axi-throughput-issue/m-p/4589300#M240634 )
8x8:8 means a radio could listen (Rx) and transmit (Tx) using 8 independent streams and that is good because each stream increases the throughput. So, if I can send 100 Mbps on 1 stream, 8 streams means that I could send 800 Mbps at the same time. In theory this sounds better then 2x2:2 (200 Mbps) or 4x4:4 (400 Mbps) but in real life and most of the scenarios it is not quite like this. In most of the real-life scenarios, with the current technology, you just have 200 Mbps no matter a 2x2:2, a 4x4:4 or an 8x8:8. And depending on factors that are more important than the numbers of antenna and streams you could have much less, or you can get more from a 2x2:2 than an 8x8:8.
I will give more details below but for simplicity I will equal 1 antenna with one stream. You could have 2 antennas and 1 stream and that will increase the reliability of the Tx/Rx (less re-transmits). But for simplicity and max throughput as a scope I will ignore this capability (hoping that this is implemented properly I recommend a 4x4 AP).
Let’s start assuming a 1x1:1 TX radio (ap) and an 1x1:1 RX radio (desktop). So, 1 stream transmitted and received. How much data can be downloaded per second by the desktop Pc?
First thing that matters is the distance between the AP and the PC.
That is the most important thing in my opinion (location, location, location ). You can find this as the MCS index (for the professionals on this forum, a know this explanation is not quite technically accurate but I try to explain it for people like me). For simplicity I use only the WiFi 6 standard (5ghz ax) but the principle is the same for all the other standards.
MCS index varies from 0 to 11 for 5Ghz ax.
Second most important thing is the channel width.
5Ghz ax can operate using a 20, 40, 80, 160 Mhz. Same as streams, the channel width directly influences the throughput. If the connection allows 100 Mbps using a 20 Mhz channel, changing it to a 40 Mhz could double the throughput (200 Mbps; assuming that there is no interference on the channels)
Now to put these in our example:
1 5Ghz ax stream using a 20Mhz channel at MCS 0 – 4.3 Mbps
1 5Ghz ax stream using a 20Mhz channel at MCS 11 – 143 Mbps (I hope this is enough to see how important the proximity is)
1 5Ghz ax stream using a 160Mhz channel width at MCS 11 – 1201 Mbps (the importance to channel width maximization)
Now, on an 8x8:8 ap you could say wow I can get 8 * 1201 Mbps. Not quite as an 8x8 setup could only be used with a max 80Mhz channel width but is still impressive (4804 Mbps).
The new C9136ax cand do theoretically 10.2 Gbps (4x4 160 MHz on 6 GHz, 8x8 80 MHz on 5-GHz, and 4x4 20 MHz on 2.4-GHz)
Those speeds are theoretical and in an environment with no other interferences (like neighbor’s Aps) you could obtain 50% - 60% depending on other variable like number of devices and number of SSIDs per radio.
Still a 50% of 4804 is very good but unfortunately there are other things that we need to consider.
First the AP might have 8 antennas, but the vast majority devices used in the workplace (desktops, laptops, mobile phones, tablets) have only 2 antennas and can use maximum an 80Mhz channel width.
So, they can achieve a maximum throughput of 1200 Mbps. Even worse as most of them are still wifi 5 they cap at 866 Mbps.
So, if that desktop is a 2–3-year-old business pc most probably it could download some files at maximum 550 Mbps in an environment with no interferences and no other devices connected to the AP. In the moment you will add another 2x2:2 device that throughput will be divided between the two and each will probably reach a 250 Mbps max (if they download the files at the same time). This because the air is a shared medium and the devices wait to communicate with the AP. That 866 Mbps channel is divided between the devices that use it. If you have 10 devices, well probably each will get a 30 Mbps real throughput (or even less).
To maximize the use of more antenna there is the MU-MIMO technology.
This means that the 8x8:8 radio could communicate with 4 2x2:2 devices at the same time. I this case all 4 devices could get the theoretical 866 Mbps throughput.
The only requirement is that all those devices to have MU-MIMO capabilities. The problem is that for example no Apple Wi-Fi 6 products has it (as per their specs). This means that even if you have an AP with an 8x8:8 radio it will work similar with at 2x2:2 from the throughput perspective. So, instead of a one 8x8:8 you could do much better with 2 2x2:2.
As most of the connected devices use 2x2:2 radios until the majority implement MU-MIMO I see no point of buying APs with 8x8 radios.
I bought one because of my specific work setup (low density, high throughput) and the fact that it can be used as dual 4x4:4 in the 5Ghz band and I couldn’t run additional cables for more APs.
(I assume that not working as it supposed to is a bug not a falsely advertised capability.)
There are specific scenarios, stadiums, warehouses, concert halls, etc. when a C9130axe with specialized antenna could be a game changer but for those setups I recommend working with a consultant
Also there are other things that influence the total throughput, but I focused only on the ones related to the main questions (What does it mean by 8:8x8? Do we really need 8:8x8?)
