Unifi system, how to get the best out of it

raz77

Well-known Member
Hi I have a USG, 3 x unifi AC lite, 1 x nano HD and 1 x outdoor mesh unit. Would like advice on how to get the best out of the system. I have the nano on VHT80 auto for 5ghz and 2.4 on HT20 auto. I have this set to band steering 5ghz.

I have all other units set to 5ghz VHT40 auto, 2.4ghz HT20 auto, the outside unit is set to 5ghz band steering while the other 3 are on balanced. To be fair since system has been installed, only thing I have changed is the band steering and on the nano changed from default VHT40 to VHT80. at the moment 30 devices are on 5ghz and 14 on 2.4ghz.
 

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raz77

Well-known Member
Hi locations are marked as red colour, this is on a outside wall, blue are inside, all are on ceiling apart from Kitchen which is on the wall. Two lites are on ground floor and second floor, first floor has nano hd, this is used allot. Kitchen has been knocked through as one whole room. The picture with the decking, the kitchen unit is up against the wall on the window above the two black doors. The outside unit is on the wall behind the decking above the black door.
 

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raz77

Well-known Member
Everything is working fine, not sure I am getting the best out of the system. My old Bt disc on the first floor used would show my iPad at 410mbs on speedtest app, I get around 270mbs. The unifi seems to be giving everything in the house a better stable connection, just not maybe the fastest.
 

raz77

Well-known Member
Now I have one cat5e cable going to a switch on the first floor, switch is 1gbs enabled, I have the ground floor, first floor and second floor AP connected to this., I have other switch’s around the house, I tend to have most things using a wired connection if I can.
 

raz77

Well-known Member
This is what the Controller is reporting
 

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mickevh

Distinguished Member
With so many AP's relatively close together, there's no chance of creating a channel plan in the 2.4GHz waveband where cells don't interfere with each other, especially if you use 40MHz "fat" channels available in the N protocol. The best you could do is one 20MHz channel and one 40MHz channel and that's its.

So on big deployments, I restrict 2.4GHz to 20MHz channels only, which means I can have (usually) 1,6,11 and see if I can arrange the hotspots to get the AP's on the same channel as far apart as possible. Even then, it might not be possible, to I use a 1,5,9,13 channel plan and even they are bumping into each other a bit.

That hits link rate on any given client using N in the 2.4Ghz waveaband (basically it's half what it could be) but with more cells and less co-channel interference you end up with higher overall throughput for the entire system as a whole. It not all about the "numbers" you see on any given client, it's about the "air time."

For example, if I've got a client that could potentially achieve 300mbps (nominal) link rate with 40MHz channels, but that client only gets to transmit a 1/10th of the time because it's having to "play nice" with so many other devices in one big "cell," it might actually get better performance with a 150mbps link rate, but it's able to transmit 50% if the time because is in a smaller cell with fewer other devices and therefore getting better air time use.

Welcome to the black art of large network planning! Deep init..? :D

In the 5GHz waveband, there's way more channels available so go for the almost the full beans. For the ultimate in AC it's 160MHz channels, though again we run into bandwidth starvation, so I've probably go for 80MHz channels in AC and definitely 40MHz for N/AC.

Also, bear in mind that an outdoor antenna has some additional restrictions on transmit power and channel usage (to avoid aircraft RADAR.) It's why a lot of kit will ask you whether an AP is for indoor or outdoor use, so it can set it up accordingly.

For relatively few AP's I'd probably try to map out my out channel plan and manually configure it rather than rely on the automation to do it. For best results, you'd want to try and avoid the neighbours if you have any which may need you to wander around with a sniffer like InSSIDer or acrylic Wi-Fi to see what they are transmitting on.
 

raz77

Well-known Member
Hi to map out channel plan, do I use the free scan in tools section of each AP, do I do this for both 5 and 2g. As most of my WiFi clients are on 5G, for the 2g, which ap would you put on 20 and which ones on 40. So you saying I am best coming off auto on all AP and manually set them? You not joking about the black art of networking 😔
 

raz77

Well-known Member
InSSIDer is allot cheaper, would I just need the free version or would I need the one with Meta geek plus?
 

mickevh

Distinguished Member
Whilst looking for some images to illustrate channel planning, I've happened across a blog piece from Ekahau (a well respected vendor of channel planning and analysis tools) which contains some nice graphics. (And gratifyingly form my perspective, echos I've said - smug mode engaged.) You might care to have a look... Channel Planning Best Practices for Better Wi-Fi

The sort of Wi-Fi scanning tools I've mentioned don't scan "AP by AP" they "sniff" all the available radio channels and report back which SSID's they can see being advertised. (Technically, they miss an awful lot of Wi-Fi traffic and don't show any clients.) They do this by "frog hopping" through all the available radio channels, listen out for a bit for a particular type of Wi-Fi packet (called a "beacon" - AP's send them out periodically to announce their presence) then tabulate the results and confect some pretty graphs. As well as the presence of each AP, they also report the signal strength (RSSI in the jargon) that they received the beacon.

So you can wander around with a device running such a sniffer, (laptop is ideal) and see what you can see where, what channels it's using and how the RSSI varies as you move around - don't worry too much about the actually RSSI values which will bounce around a bit, look for the trend.

The freebies tools I've mentioned do both wavebands at the same time (albeit frog hopping through them as I've described) though of course, you'll need a dual-band laptop to do this (my current home lappy is 2.4GHz only, so can't see anything 5GHz as it lacks 5Ghz radios.)

There's proably some phone/tablet apps that do the same thing if you prefer those platforms, but I've never used any and again you need to ensure the phone/tablet you run them on is dual band if you want to survey both wavebands.
 
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mickevh

Distinguished Member
For basic planning, don't worry about the paid for versions - for a smallish SOHO, the freebies will give you the basics.
 

raz77

Well-known Member
Right will have to download and see what the laptop shows. This is what things are connected to at the moment.
 

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mickevh

Distinguished Member
InSSIDer et al won't show that - just the AP's.

Strictly speaking, it's the SSID's being advertised - in a AP advertising multiple SSID (corproate kit often does this, some better SOHO's might offer "normal" and "guest" SSIDs, or things like BT's FON) so an AP advertising more than one SSID will be listed twice. It's only a one-to-one correspondence between SSID and physical AP in AP's that only advertise a single SSID, but that's most SOHO kit.

What you do get is the channels they are using and the "fatness" of those channels.

They are pretty intuative tools, I doubt it'll take you long to figure out what you are looking at.
 

raz77

Well-known Member
Once I have settled on the channels, what about power settings, do I leave on auto for the ones I have selected?
 

mickevh

Distinguished Member
Leave the Tx power on auto. It'll probably transmit at max. power unless it decides it can tweak it down a bit.

With relatively few AP's and some significant amounts of structure (walls) between your AP's and clients, you probably want the max. - especially in 5GHz

Tuning down the Tx power is one of the "tricks" we (network nerds) used in environments with lots of clients and lots of AP's to try and encourage clients to roam more quickly. It's a bit of an "old school" approach these days as there's now protocols in the Wi-Fi standards that allow AP's to talk to each other about which AP can "hear" which client the best, then send a kind of "hint" to clients that they might be better off if they roamed. Likewise bandwidth steering. Taking advantage of automation like this is kind of "the point" of having an integrated fleet of managed AP's.

Not all clients are "hint compliant" and even if they are, they don't have to "take the hint" (sorry - I can never resist that pun) - it's still the case that it's the client that decides if/when to roam or jump wavebands. But going forwards, increasing numbers of clients will be "hint" compliant.
 

raz77

Well-known Member
@mickevh all working well now, this is what I have set it to

Garden: 11 2G 20mhz, 38 5G 40mhz
Kitchen: 1 2G 20mhz, 46 5G 40mhz
Ground floor: 6 2G 20mhz, 46 5G 40mhz
First floor :1 2G 20mhz, 42 5G 80mhz
Second floor : 11 2G 20mhz, 38 5G 40mhz

Garden and first floor are on 5ghz band steering while other 3 are on balanced.


Thanks for all your help.
 

mickevh

Distinguished Member
That's about what I'd do. Though you've got two ground floor AP's on the same 5GHz channel (46) you might want to tweak that a bit. Unless the Unifi "only" giving you a choice of two 40Ghz channels. (A lot of low end SOHO cannot use the "DFS" 5Ghz channels.)

I'd perhaps go for 80MHz channels on the the other AP's - it's only AC devices that are capable of using it presently and even then they only "bond" the multiple 20Mhz channels together to form the 80MHz channel when they have a packet that's big enough that is needs it. If sending something "small" enough to fit into a 20MHz, then they just use it 20Mhz (likewise 40Mhz.) Ditto N and 40Mhz.

It's "expensive" in terms of air time use to "clear out" (silence) multiple 20Mhz channels to bind them up into fatter channels, so a lot of kit only bothers when it's worth the effort - ie they have big enough packets to send to make it worthwhile.

So, if your kit will let you, in the 2GHz band I'd force everything to 20MHz only, but in 5GHz let it "auto" select the channel width, but base the tuning plan on the "nominal" 40Mhz channels you've selected.

Live with it for a few weeks and see how you get on. If it's all good, then leave it be, if you find problems, then perhaps consider a change. It can drive you bonkers trying to get a Wi-Fi deployment "just so" and the whole thing is something of a moveable feast in any case. For example, you may think you've chosen the best channel plan to avoid the neighbours (tick, gold star) but after a week the neighbours change channels (because their kit auto-tunes) and ruins your carefully confected plan. You could change in repsonse, only to rinse and repeat a few weeks later - you can end up chasing your tail forever.

I live in flats and now that everyone has Wi-Fi, the bleed through from the neighbours is horrendous and I long since gave up optimising it only to watch it fall apart a few days later. I tend to be a bit "zen" about nowadays - I picked a channel plan and just leave it alone now. It's working well enough for my needs 95% of the time.
 
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raz77

Well-known Member
So should I change the 5ghz to auto on the 40mhz?, nano on first floor is on 80mhz as its 4x4 where as lites are only 2x2 on the 5g. I tried one of the lites on 80mhz on the second floor and was getting issues. I see channels labelled DFS, just did not use them. On the 40hz I have channels 36, 40, 44, 48, 52-136 DFS.
 

mickevh

Distinguished Member
If you've got DFS channels available then go for them - it gives you much more bandwidth (channel numbers) to play with.

The "deal" with DFS is that there are some other "applications" that also use the same radio frequencies and have to be given priority. Typically this is weather RADAR for aircraft, coast guard stations and so forth. What's supposed to happen is that if any of these "other" applications are detected nearby, the AP's are supposed to the shut down the channel they are using and change to a different one. (Hence cheap SOHO often omits DFS channels because of the extra "processing" required to cope with it.) One of my big deployments was under the approaches into Heathrow and on the days they were on Easterly Ops and we were being overflown by low altitude aircraft all day, our AP's would be whinging like mad!

But if you're not near an airport, then there's no reason to shy away from the DFS channels (unless you've got clients that cannot tune them) - especially for indoor use. It's certainly worth a try as it'll cost nothing to give a test for a few weeks.

The "fatness" of the channels is not related to the number of antenna your kit has - the antenna count affects something else called the number of "spacial streams" that can be used. Basically, in N & AC with multiple antenna different data gets transmitted out of each antenna which increases the throughput. So the "speed" you observe for any given packet (actually, it's better to think of it in terms of the numbers of bits transmitted per unit of time) is the product of the number of special streams that can be maintained between station (basically the antenna count) and the channel fatness. Then add in the FEC overheards, modulation scheme and so on.

So it's fine to use fat channel however many antenna you have. Doubling the channel width (roughly) doubles the speed, doubling the antenna count (#spacial streams) (roughly) doubles it again.

Wiki's articles on 802.11N and 802.11AC used to have some tables laying out modulation scheme, channel width, spacial stream count and the link rate ("speed") that the various permutations would deliver.
 
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mickevh

Distinguished Member
Not many client devices have 4 antenna, so you're unlikely to see the "better than gigabit" link rates that 4x4 MIMO in AC can theoretically run at.

More usefully your 4x4 antenna array might be capable of "beam-forming" (which uses phase difference to "steer" the radiation pattern a bit and give better signal at any give location,) and/or it might be capable of "MU-MIMO" which basically means the AP can transmit to multiple clients simultaneously (if the clients are physically far enough apart.) To know whether your kit does any of this, and whether you have clients that can utilise such techniques, you'd need to dig into the details of the specifications.
 

raz77

Well-known Member
If I switch over to DFS channels, do is stick to 40mhz or 80 MHz. Do I also just choice a different DFS channel for each AP or are there any channels that overlap to stay away from in the DFS range. All my AP are inside apart from the one in the garden, that’s probably best staying on a channel between 38-46.
 

mickevh

Distinguished Member
I'd still give VHT80 a go - about the only time I'd think about disabling it is if I knew I didn't have any AC clients that can use it (so no point) or I couldn't use the DFS channels because my kit didn't support them (ie I'm bandwidth constrained.)

You can usually pick your channel plan for DFS channels just the same as the non-DFS ones (at least, in the kit I've used) - just don't be surprised if you check back one day and find they have have magically changed. DFS is just like that - even when you opt for a "fixed" channel plan, it can change when you're not looking.

The Ekahau article I linked a few posts back has quite a nice graphic illustrating how the channels overlap - it's about the 4th graphic down.

I'd try the outdoor antenna on one of the non-DFS channels so if I am unlucky enough to get clobbered by DFS it won't be affected, the indoor antenna are "shielded" somewhat by the shell of the building.
 

raz77

Well-known Member
If I choose a DFS channel, if a device is not ac compliant but can still use 5g, will it still connect. Just changed second floor to 80ghz and DFS 60, will change kitchen and ground floor to DFS 100 and 80hz and kitchen to 80hz and DFS 52
 

mickevh

Distinguished Member
I don't know the nomenclature of Unifi - but you're aiming for a sort of "80/Auto" - ie it's nominally an 80MHz channel, but it'll automatically use 20/40/80 as appropriate to the client and/or the data capacity requirements.

The Wi-FI protocols (A/B/G/N/AC) are all designed to be backwards compatible. Usually you find multiple protocols delivered over the same radio channel.

Which protocols are supported in which waveband is specified in the standards. B/G are 2.4Ghz only. A/AC are 5Ghz only. N can be provided in either waveband, but it's not mandatory to offer it on/either both. These day though, most modern kit does.

In better kit, you get to pick and choose which protocol is enabled for each waveband, subject to the rules of which protocols can operating in which waveband.

B is ancient history these days, so I wouldn't bother using it at all unless you have something that can only talk "B." These days one could probably say the same for A/G. If all you clients are N and/or AC capable, then just enable those protocols.

So, for example, let's assume for the purposes of debate your client base are all N and/or AC capable.

In 2.4GHz, turn on N, turn off B/G, fix the channel width at 20MHz, deploy the tuning plan as you designed it (seems OK to me) and you're probably done. If you've got some old "2.4Ghz only" clients that cannot talk "N" at 2.4Ghz but are G capable, you might consider enabling G.

Similarly, in 5GHz, turn on N & AC, turn off A, try out 80Mhz/auto, deploy your channel plan and see how you get on. Again, if you have some 5Ghz client that cannot "talk" N or AC and only do A, you might turn A back on. But at time of posting it's highly unlikely you've got any "A" only 5Ghz clients.

When a client binds to AP (called "Associate" in Wi-Fi speak) part of the negotiation that takes place is that client and AP agree what "protocol" they are going to talk to each other and part of the protocol specification is things like the channel width. Thusly, if an N client Associates with an AP offering N/AC in 5Ghz, the AP "knows" that the N client cannot "talk" AC c/w it's 80Mhz channels, so it will restrict itself to 20/40MHz channels for the N client using the N protocol, because the AP knows what N protocol mandates. It'll only ever use 80MHz channels for AC clients, and even then, not all of them support it.
 
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raz77

Well-known Member
All my Logitech security cameras don’t seem to to like 80mz, I have set the three lite units, ground, kitchen and second floor to all 80 and auto.
 

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