At a Loss: Non-stop issues with small business network

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Thumpasaur

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A friend forwarded me to a small local business that needed help with their wireless network and PoS printers. I've almost lost count of how many times I've either got called back in late at night or frustrated text messages of their system not working as intended. I should also add that I have an intermediate level of knowledge about networking, but am by no means an expert; my primary focus is hardware repair.

Anyway, so this is the setup. They have two iPads with the PoS software that connect to an Apple Airport that acts as the "POS" wireless connection - which also controls one USB TM-T88V PoS printer. There are two debit terminals that connect via a wired connection. The second TM-T88V PoS printer has a NIC and is connected via ethernet cable. On top of which, they wanted a guest network setup.

Here's what the network looks like:

Router: D-Link DIR-850L

WiFi Networks
1. "<restaurant name> Admin"
2. "<restaurant name> POS"
3. "<restaurant name> Guest"

Static IPs
192.168.0.1 - Default Gateway
192.168.0.2 - Debit Terminal #1
192.168.0.3 - Debit Terminal #2
192.168.0.4 - Apple Airport -> 2x iPads + 1x USB PoS printer ("<restaurant name> POS")
192.168.0.5 - PoS Printer
192.168.0.6 - iPad to control music

Then I have a DHCP server setup with the range of IPs 192.168.0.10 to 192.168.0.200 for guest devices.

I should add that I wanted to get rid of the Apple Airport by trying to connect the USB printer into the router directly, but sadly it didn't work.

When I go in before the place opens, everything on the network works fine. The debit terminals accept transactions, the POS iPads print receipts no problem, and their iPads for music plays music from youtube without issue. However, later in the evening when guests connect, things go south and I get text messages.

Any ideas?
 
Solution
jsmithepa
QOS not an easy subject for the beginner. Let try the following see if it helps:

In its most simplest form I call QOS Priority Queuing.

Is like having multiple check out lanes, you (1)filter the traffic, and assign type of traffic into lanes, the filters can be simple or complex depending on router's implementation, then (2)the router will process each queue with speed depending on their priority, so low priority queues are serviced with slowest frequency.

So QOS doesn't stop anything, it allows everybody to have a chance, while making high priority traffic types (1st class lines?) to go through faster than the coach people.

In your environment, I would certainly disallow, or severely slow down video streaming. To disable traffic...
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audie-tron25

audie-tron25

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Mar 23, 2015
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Sounds like it could be anything. Just want to clarify, the Airport is running the POS Wifi and the printer but no other wired connections? Is the TP-Link hosting the "Admin" and "Guest" Wifi networks as well as the debit terminals?

It's possible they're running into a limit on the max number of wireless users on the D-Link (recommends a max of 16) and depending on the device (haven't used one of those before), it may affect the Airport. I would ask them to disable the "Guest" network for a day and see whether that solves any issues. I have encountered a few WiFi routers (usually cheaper models from ISP's) which do get a bit upset when >16 devices are connected.

I'm hesitant to say the Airport is faulty because if it shouldn't affect the rest of the network unless it's been configured incorrectly. The only thing here is to make sure it is in AP Mode (not sure what the setting is for the Airport in particular). I'm sure it's correct but just something to check anyway. Easiest way here is to check the IP addresses being given to devices on the Guest or Admin networks to see if they are being given IP addresses in the DHCP range you've set (X.X.X.11 or higher).

It's kind of hard to say but is it possible that a user on the "Guest" network is abusing the network? Downloading lots of things or streaming video in high resolutions etc. What is the rough connection speed of the business (eg <10Mb/s etc)? Also is it ADSL or Cable?

Is there any other details that they can give you about their issues:
- Is it just the devices connected to the "POS" network having issues?
- What about the "Guest" network?
- Are the (wired) debit terminals affected?
- What issues are they having in particular (WiFi dropouts, connections failing/spotty, slow loading etc)?

Sounds like you might be in a bit of a pickle. Hope these ideas help though :)
 
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Thumpasaur

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Thanks for the input! I'm going to try running the router with the Guest network disabled for tomorrow to see how things go. I think jsmithepa is right on all points. So I'll have to recommend upgrading a more robust router in the end.

EDIT: The previous setup was a wired VPN router with the Apple Airport connected to it that provided the guest network and wireless connectivity for the POS iPads. My question: is using the airport as a guest network and PoS connectivity safe? The airport was assigning 10.0.0.x IPs. If it is, I could go back to that setup, ya?
 
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failboat

failboat

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ubiquiti has great equipment.

there is no difference between 192.168. and 10. ips they are both private.

using some limiters at least will ensure the business network has bandwidth.
with an edge or unifi router and 1 or 2 unifi aps you can set up the VLANs.
for the guest VLAN you can do client isolation, which gives them internet only access.
all VLANs can be configured so that they can't connect to each other.
they sell a cloud key so you can remote access the network. You will have to port forward for this and pay for cloud management. this is optional, but unifi must be configured from unifi controller on windows or another client with the app installed. the controller configs all unifi equipment. the edge line is different and not in the unifi controller.
 
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Thumpasaur

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Thanks for the info! For now, I've setup the QoS engine and wanted to be sure if it's setup correctly via the image below. Before setting it up, I used speedtest.net and the package the client has is 20/10 Mbps; is this too slow to sustain a guest network and should I recommend a faster package? Also, are the speeds I set in the QoS too low and could they cause the internet to cut out on devices? Lastly, after setting up the QoS Engine, I did another speedtest.net test on my phone - while connected to the wireless network - and it still read 20 Mbps, not 1 Mbps as seen below. Does speedtest.net bypass the QoS engine?
G6IJ2dd.png
 
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failboat

failboat

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qdisc based qos is bandwidth conserving. meaning it shares the total bandwidth. limiters are not. they cap speeds.

to test the qdisc you need to use bandwidth from different priorities.

I'd suggest keeping it simple. Try testing only with local ips.
Put the guest range on low and put the business on high.

If that's a true fair queue, it's already servicing flows in round robin. meaning that flows in the same class are serviced equally.
class setup may not be needed.
try running two speed tests at the same time and see if they both have half the band.
the weights help move more band to certain classes.

the best fair queue qos is fq_codel. it also manages the buffer so that the largest flows buffer and smaller ones don't. this keeps small flows moving. all the ubiquiti stuff has it.

the only two easy to configure shaping methods are setting limiters on interfaces and using fair queue.
any class or priority queue is very hard to setup and work perfect in every case.
qdisc use a lot of cpu. some can't keep up and will bottleneck your traffic. a lot should be able to handle 20Mbs.
the more rules you add it might dip.
 
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Thumpasaur

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Hmm, a lot of that is over my head, lol.

I'm not familiar with qdisc. Also, I'm not sure I follow when you say "test with local ips" and "put the guest range on low and put the bandwidth on high". Hmm, I might need to suggest to my friend (the business owner) that he may need to consult a networking expert/technician :/

EDIT: Saw your edit and testing multiple devices at the same time makes sense, I'll give that a shot tomorrow, thanks! Though, I wanted to be sure, are the QoS transmission values I put in too low?
 
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failboat

failboat

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I'm not sure what all those rules will match for you. it probably won't figure out whats youtube and whats not.
 
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Thumpasaur

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Yea I'm not sure how any of those work, those were default values.
 
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jsmithepa

jsmithepa

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QOS not an easy subject for the beginner. Let try the following see if it helps:

In its most simplest form I call QOS Priority Queuing.

Is like having multiple check out lanes, you (1)filter the traffic, and assign type of traffic into lanes, the filters can be simple or complex depending on router's implementation, then (2)the router will process each queue with speed depending on their priority, so low priority queues are serviced with slowest frequency.

So QOS doesn't stop anything, it allows everybody to have a chance, while making high priority traffic types (1st class lines?) to go through faster than the coach people.

In your environment, I would certainly disallow, or severely slow down video streaming. To disable traffic completely, I don't remember, but could be under FILTER or FIREWALL or ACESS LIST.

Good luck.
 
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Thumpasaur

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That explanation definitely helps, thanks!
 
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