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farisr
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Ubiquity to Mikrotik at a caravan park

Wed Feb 03, 2021 3:54 pm

I need help with setting up a Microtik-based WiFi network to replace a Ubiquiti-based one please. I hope I'm posting in the correct section of the forum?

Some years ago, I designed and set up (and still manage) a WiFi network for visitors/residents to get access to the Internet at a reasonably large caravan park (aka trailer park).

It is all currently based on Ubiquiti outdoor APs (mainly 2.4Ghz Rocket M2 radios and high gain 90 degree sector antennas), linked to a Zyxel hospitality gateway to deal with access control (via vouchers printed on dedicated ticket printers) and per-user bandwidth limiting.

The current system has been in place for-- it must be 8 years now -- and until a year or so ago had been working flawlessly. No real complaints from users. Everybody was really happy - especially the owner of the park.

But recently things have been going downhill, with users complaining about speeds, problems connecting, randomly disconnecting and various other mysterious things that I just cannot reproduce in my tests no matter how hard I try. I can't detect any obvious bottlenecks either, and the internet backhaul is nowhere near saturated. Still, something is obviously wrong, or sub-par anyway.

Obviously in recent years the way people use the Internet has changed, and the number of devices they have has multiplied. And the kit I'm using is also really quite old, and maybe just not up to what I'm expecting of it anymore. Or maybe users are expecting an experience more like they get at home, and don't understand the limitations of public WiFi? I just don't know.

Either way, the existing kit is definitely old so I figure it is time to rip out the old and start afresh - this time with MikroTik kit.
The problem is that I just don't know MikroTik kit and its limitations and advantages at all well, nor if I'm even doing things the right way by modern standards and thinking, so I'm hoping the experienced expert users on this forum will assist me.

I must add a disclaimer here. I don't consider myself a WiFi professional - although I like to think I *think* I know more than enough to at least stay out of trouble. Still, this is not my "day job" ( computer/server/technical/network sort of role). The owner of the park is fully aware of my limitations. We've worked very well together on various technical projects. Neither of us expects miracles, but both of us want a reliable, sensible solution that doesn't cost the earth and will last another 5 years or so.

I've chosen Mikrotik as an alternative to Ubiquiti on instinct alone. Sure Ubiquiti has all sorts of new kit to play with, but.....I don't know. It just doesn't seem to fit in with my way of thinking. And I'm not happy with how many times they've released really buggy firmware. Mikrotik kit seems to be more....flexible. More mature, somehow. I hope I'm right about this.

Anyway...if you've persevered with this long message so far, I'm kind of hoping you'll stick with me and maybe read the rest - please?

The caravan/trailer park isn't rectangular, but think of it as roughly 400mx300m.
It mostly consists of "static" aluminium-sided caravans (trailers) but there are also some of the mobile kind you tow behind your car.

Residents/visitors living in these caravans connect their phones/tablets/laptops/whatever directly to the WiFi network to get internet access, having paid for a voucher with a time-limited username/password managed by the Zyxel hospitality gateway.

We currently have four main "towers", roughly(ish) at the edges of the park, each with two or three 90 degree sector antennas (2.4Ghz, 19dB gain if I recall correctly) each sector powered by its own Rocket M2 (2X2) radios (APs) on a different, non-overlapping channel (although there's no RF shielding to stop one AP interfering with any of the others - they are in close proximity).

In my tests, these give great, reliable coverage everywhere required, even when the park is full of residents/visitors. There are some areas where channels from one tower overlap the same channels from another tower, but I don't think it is too much of a problem and it is in very limited areas and the extreme range of the APs.

We don't see more than 25 to 30 concurrent users on each AP (and I don't think they are capable of handling more reliably and then there's the hidden node issue anyway).
[my desire is for each radio to handle 60+ concurrent users per AP for future-proofing]

And I've not seen more than 250 concurrent users on the current system
.

To replace the Rocket M2s and 90 degree sectors, I'm thinking in terms of the mANTBox 52 15s. The idea is to have 5Ghz and 2.4Ghz available for users to connect to, increasing the number of concurrent users per AP and hopefully later reducing or eliminating 2.4Ghz channel overlap.

My only real concern is that the gain is lower than the current setup (15dB I think) at 2.4Ghz. Obviously the range at 5Ghz will be shorter than at 2.4Ghz and I'm not sure about those aluminium sides on the static caravans at 5Ghz. But without doing some actual tests with some actual kit (which I plan on doing) I won't know if this is a good decision or a bad one. Some comments on this would be appreciated.

Three of the towers are linked back to what I'll call HQ (where the Internet backhaul, switches and gateway live) via 5Ghz Point to Point links (Uniquiti RocketDish M5). These have clear line of sight but even so, the current radios are I think limited to around 100Mbit/sec duplex at best. Something at the back of my mind says maybe this isn't always enough, even though I've not seen them saturated.

I have no idea what to replace these with. The distances aren't great (between 100m and 250m) but we get a lot of rain - heavy rain - so we need the signal to survive that.

All of the above assumes we stick with large, powerful, sensitive radios and antennas on the outskirts-ish of the park. I don't want ugly towers in the middle of it, that's for sure.
But a lot of the kit distributors I've spoken to have been suggesting a total re-think, and to use a network of smaller, less conspicuous APs dotted around the park, with maybe 5Ghz WiFi backhaul to the bigger APs on the outskirts (because we can't arrange physical ethernet cables to any new APs - we'd have to dig up half the park to do that and it just isn't possible).

This lots of smaller APs option seems sensible, but ideally I don't want a bunch of poles with APs all over the place (there are no tall light poles to attach to - lighting is provided by low level knee-height things). Also, if we use the kind of kit they suggest (Mesh-capable outdoor units with users connecting at 2.4Ghz and 5Ghz backhaul to the existing towers) then there could be serious 2.4Ghz channel overlap unless you spent forever adjusting power output and dealing with the resulting notspots.

Arrgh! I find it so frustrating. I just don't know what to do here. Instinct says avoid lots of small APs and stick with the big towers on the outskirts (but with 5Ghz and 2.4Ghz available for users to connect to), maybe add a couple of smaller APs somewhere to maybe improve things. But maybe my instinct and thinking is old fashioned? Comments please?

And then I need to replace the Zyxel hospitality gateway with something else. Zyxel stopped supporting the model we use some years ago. What made it attractive in the first place is that you can attach dedicated voucher ticket printers to the network. Using printed access vouchers is important to the customer. The owner isn't keen on self-serve access (e.g. online signup and payment), although that may change. So they currently want to be able to sell physical tickets with a time-limited username/password combo (e.g. 24 hrs access, 7 days, 1 month). I know RouterOS with some additional stuff can do this, but I'm not sure of anything beyond that. Pre-printed tickets would be perfectly acceptable instead of printing on-demand - I know that using this method would be a lot easier than trying to find a system that can print on demand.

And also I need to be able to manage all the APs remotely, ideally via a single management application.

Wow. Long message. Sorry. Lots of info, but maybe still lacking very much detail.

Still, I'm hoping the message isn't too long and it won't put people off responding.

Your expert and experienced comments would be very much appreciated, even if you tell me I'm nuts and I'm doing everything incorrectly.
 
gotsprings
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Re: Ubiquity to Mikrotik at a caravan park

Sat Feb 06, 2021 5:54 pm

RVs have metal skins... Penetration each way is the first issue you have to chase.

So more APs, turned down, with smaller channel widths.
"It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so."
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bpwl
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Re: Ubiquity to Mikrotik at a caravan park

Sun Feb 07, 2021 2:06 am

Just some general thoughts. Good description of the existing installation, and some constraints for the new installation.
However the service you want to deliver needs more details.
What should the users be able of doing, and how many simultaneously? (video watching, uploading tiktok, gaming, simple web surfing, ...)
and on what kind of device smartphone/wearables/tablets/laptop.
I understand they want to be able to use it inside as well. A challenge with only outside AP coverage.
What is the overall internet uplink speed ?
What is outside (or even in) this camping area on wifi material. Wifi can interfere over more than 500 meters. Neighbors can take a large chunk of the total wifi airtime.
But even these days mifi units (mobile hotspots) are brought in. A smartphone with hotspot enabled is an AP competing for airtime.

Your current model is one of coverage, this was very common 10 to even 5 years ago. Today you also need to look at capacity. Sharing a limited bandwidth with so many users can give a very low per device throughput.

There is no silver bullet solution. But after replacing an almost dead wifi environment based on 4 strong outdoor AP, and all airtime wasted by the beacons from 24 neighbor AP, I know somewhat the challenge, and have followed other attempts to solve/tune it.
viewtopic.php?f=7&t=164236

Just to help your thinking ....
- airtime is precious. You want everyone to have a fast wifi connection. Not only to please them, but to limit their use of airtime. One slow user will slow down everyone on that channel.
- on 2.4 GHz you have only 3 nonoverlapping channels. 1-6-11 (some go for 1-5-9-13 outside FCC regulation). The wifi signal causing airtime-wait goes much further than the usable range. 8 times (-88 dBm) wider than the usable (-70 dBm) signal. So if the AP is usable for 50 meter the co-channel interference goes 400 meter. If you lower the power to reduce that, you also lower the interface rate for the users, and that increases the airtime. Solving the interference problem with TX power of the AP is not do-able with 2.4 GHz. The interference (wait) is not only in the spot where you can use both signals, it's all over the place. (The 4 corner AP, but also neighbors, mifi hotspot, repeaters, ... all 8 times their usable range)
- aluminum is an ideal shield for wifi RF signals. The signal reduction will be significant inside, and even bigger for 5 GHz.
- More AP do not increase the available airtime. But they can reduce the airtime needed to transmit a certain volume, because of the higher rate
- little small AP will have a more balanced antenna-gain compared to the client device. A client device will have difficulty in receiving a 14dBi antenna-gain AP limited by EIRP regulations. The AP will receive the client well due to the 14 dBi antenna gain amplification. That AP will receive and wait for any wifi activity in its channel over a very long distance
- number of outdoor 5 GHz channels greatly depends on the region you are in. Not all client devices can use those channels.

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