Mixing 802.11n with 802.11ac APs

[patoberli]

Hello

I'm very soon starting to install new 802.11ac (3702) APs into my network. This is a building with a lot of rooms, separated with thin metal+plaster walls and sometimes with cement walls. The current setup is to have in around every second room a 3502 802.11n AP.

The future design will probably require an AP in every room (up to 50 clients per room of which up to 30 should do VMware VDI, while other users will watch videos in the internet and transfer files from/to the central storage and internet) because of bandwidth requirements. A test with a 3502 in the other room with some students had shown a not high enough data rate with a low enough network latency.

What would you suggest now, should I put all the 802.11ac AP to one side of the building while I have all 802.11n AP on the other side? I currently fear that the clients might attach to the 802.11ac one (which might be in the next room) with a lower data rate instead of the in-room one with a higher data rate.

Do you have any experience with the?

The budget currently does not allow a complete replacement (also the 3502 are sufficient when in the same room as the clients).

Oh and I also already have a fairly "hot" 2.4 GHz band. I decided to start with 40 MHz 802.11ac channels. 80 MHz would leave me with only 4 channels, some of which are in the DFS band, which is here sadly in use by some radar devices from time to time.

[Leo Laohoo]

What is your uplink speed from your access switches?

[patoberli]

Uplink speed from switches is 1 Gbit/s to the distribution layer, which is 10 Gbit/s. Switch uplink load is currently very small.

[George Stefanick]

Here is what I would do ...

1) Figure out the math .. How many clients and average bandwidth need. Consider client make up 11an and 11ac. This will drive how many APs you need. 

2) I would suggest moving to a 5 GHz only network and not allow clients to switch to 2.4 Ghz.

3) I would stick with 40 Mhz channels. 

4) Stick to UNII1 and UNII2 channels.

5) I find in density indoor deployments sometimes putting APs in odd places like under desks provider better coverage for smaller cells. 

I would do a mock up and test before you invest .. 

Just my 2 cents ..

[patoberli]

I would love to do number 2), but sadly those are client owned devices and my Wifi has the requirement to be as compatible as possible. I could disable 802.11b and some of the lower 802.11a/g speeds, but that's around the best I can currently do.

The current distribution of the clients is around 55% 5 GHz and 45% 2.4 GHz. I don't really see that I can disable 2.4 GHz in the near future (read the next 2 years).

1) that is very changing. We have many "universal" classrooms and I have no influence about which class will use it. Some need high bandwidth, others need close to none.

3) I'm doing this, I haven't planned to utilize 80 MHz.

4) Sticking to those channels, U-NII3 isn't available yet for Europe. Sadly I have quite a few 'Radar' events on my current 3502 APs and thus have manually selected the channel on those.

5) Can't do. Cables are at the wall and that's where I can put the AP. Roof is in most cases also not possible.