Larger system unstable - where's the issue?

[Steve Howard]

I have been asked to 'look at' a newly installed system that will not work reliably. It consists of 12 (Uniview) wireless 4Mpixel cameras, talking back to a single 2.4G (Engenius) Access point, then onwards to a Uniview NVR. The network has a BT Hub as the router and an onward FTTC Internet connection (showing speeds of around 16/2 at most). There are also half a dozen bits of office PCs, printers etc all on the same network. I fully realise the network load here is far from ideal - but is the design poor to the point of being doomed, or can something be salvaged? The issue I am seeing is that most of the cameras connect to the AP fine, with signals strengths in the -50s and low -60s, but they refuse to stream to the NVR, and (perhaps significantly) I cannot consistently access the cameras web interface. The keyword here is 'consistent' - it's up and down all over the place. I have temporarily replaced the AP with a more modern Ubiquiti unit, and tested the cabling (AP to switch, router etc). The system is rural with no other wifi nearby. If all the cameras were attempting to stream at the same time, I'd be happy to say the issue was simply not enough wireless bandwidth, but even before I adopt the cameras to the NVR things arent stable (ie can't access the cameras UI). If I bring cameras back to the desk and connect via Ethernet, they are fine. I can normally get 3 or 4 cams working for a while - but minutes not hours. I didn't specify the initially install (and would never specify wireless like this) but has the customer now wasted their cash? Is it 'wired or die' from this point? All or any advice is very welcome here.

 

[IAmATeaf]

WiFi not worth the hassle, close the thread

If they perform better wired then id personally waste no more time then to suggest that they get cabling run before you look any further.

Having said the above, you could install multiple WiFi access points and have groups of cams set to connect to specific APs but you’d need to spend money before you’d know if it would even work.

 

[sebastiantombs]

The number of cameras, especially 4K cameras, has exceeded the bandwidth capabilities of WiFi. At best, three, or four if you're really lucky, 2MP cameras will work on 2.4GHz Wifi. Even then, frequent dropouts will happen. WiFi and security are mutually exclusive terms. Wired cameras are the ONLY way to go.

 

[Steve Howard]

The number of cameras, especially 4K cameras, has exceeded the bandwidth capabilities of WiFi. At best, three, or four if you're really lucky, 2MP cameras will work on 2.4GHz Wifi. Even then, frequent dropouts will happen. WiFi and security are mutually exclusive terms. Wired cameras are the ONLY way to go.

That was my conclusion. What confused me was the inability to see the UI of the cameras via their IPs before they were adopted to the NVR ie when no traffic was passing. Maybe I need to be a bit more methodical and retest that. Are we saying that reducing to 1080P, say 10fps, might get it working 'for now' - or likely to still exceed?

 

[sebastiantombs]

The problem is that there are too many transmitters on the same frequency. Reducing frame rates and resolution won't change that fact. None of them will get a reliable, stable, connection that lasts for more than a few seconds at a time. Ditch the WiFi and replace with wired is the only real solution. If you want to test that out, turn off all but one, then add one at a time and see what happens.

 

[samplenhold]

I started with a few WIFI cams, before I joined this forum. The whole reason I joined was I was having the same kind of inconsistent connectivity. I still use a couple of those WIFI cams, mostly to keep an eye on the dog when I am not home, and in my garage. They are constantly going offline.

One cam is across the hall, less than 10 feet, from a wireless repeater with nothing in the way, not even a wall. Goes offline several times a day. Another one is just below the WIFI router, just the floor in the way. Goes offline several times a day. Two in the garage are offline more than they are online. They are being replaced with wired cams.

WIFI is great for cellphones, tablets, and IoT things, but is not for IP cams.

 

[Steve Howard]

The problem is that there are too many transmitters on the same frequency. Reducing frame rates and resolution won't change that fact. None of them will get a reliable, stable, connection that lasts for more than a few seconds at a time. Ditch the WiFi and replace with wired is the only real solution. If you want to test that out, turn off all but one, then add one at a time and see what happens.

I agree that the bandwidth is probably overwhelmed but not "too many transmitters" - this is wifi, you can get lots of devices to play nicely, albeit at slower data rates!

 

[Ssayer]

This is an easy one. If it's just for fun, then go ahead and play with it. If it's important, you have to go wired. Period...

 

[sebastiantombs]

Too many RF sources sending data, all simultaneously, will result in bandwidth saturation. Think of it like a blivette. A blivette is ten pounds of crap in a five pound bag. Something has to give, in this case connectivity is what gives. No matter how forgiving WiFi may be, from an RF standpoint there can easily be too many transmitters on the same frequency. Video is a very "wide" signal so sliding up and down a little within the channel isn't going to work out very well since the signals will still overlap considerably. Think of it as CB channel 19 with a wide open skip situation and every CBer in the country talking at once.

 

[bp2008]

I agree that the bandwidth is probably overwhelmed but not "too many transmitters" - this is wifi, you can get lots of devices to play nicely, albeit at slower data rates!

You are right, if those transmitters are not active they should not be causing much of a problem. The question is, are those cameras really idle or are they spewing out network traffic somewhere? Never trust the camera -- always check in the router/AP to see how much throughput it is actually consuming.

Remember if the WiFi access point detects too many dropped packets, it can change automatically to a slower mode that takes a lot more airtime to transmit the same amount of data. You might have a router that advertises some BS speed like 2100 Mbps but actually achieves no more than 300 Mbps on a good day, and then you add one IP camera and suddenly your data rates are down to 14 Mbps and there's a ton of jitter and packet loss for everyone. It really doesn't take much to wreck a WiFi network.

 

[Steve Howard]

You are right, if those transmitters are not active they should not be causing much of a problem. The question is, are those cameras really idle or are they spewing out network traffic somewhere? Never trust the camera -- always check in the router/AP to see how much throughput it is actually consuming.

Remember if the WiFi access point detects too many dropped packets, it can change automatically to a slower mode that takes a lot more airtime to transmit the same amount of data. You might have a router that advertises some BS speed like 2100 Mbps but actually achieves no more than 300 Mbps on a good day, and then you add one IP camera and suddenly your data rates are down to 14 Mbps and there's a ton of jitter and packet loss for everyone. It really doesn't take much to wreck a WiFi network.

It's just 802.11n so yes, theoretically 300Mbit, but in reality, a fraction of that especially if a slow client is dragging it down. The solution I think here is clearly cabling it, I'm just bemused by the exact symptoms I'm seeing. I'm fairly sure the idle stations are indeed idle as the AP (both of them I have tried) give a total traffic count per station/IP, and idle ones are just a few kilobytes. My final experiment before I give up is going to be to take the NVR offline and see what I can see of each camera individually.

 

[Steve Howard]

Too many RF sources sending data, all simultaneously, will result in bandwidth saturation. Think of it like a blivette. A blivette is ten pounds of crap in a five pound bag. Something has to give, in this case connectivity is what gives. No matter how forgiving WiFi may be, from an RF standpoint there can easily be too many transmitters on the same frequency. Video is a very "wide" signal so sliding up and down a little within the channel isn't going to work out very well since the signals will still overlap considerably. Thin of it as CB channel 19 with a wide open skip situation and every CBer in the country talking at once.

Thanks for the reply, but you are confusing analogue video transmission with wifi (which is what we have here). Wifi is a TDMA (time division) protocol with the concept of time slots - so things don't get overrun ever at an RF level and many hundreds of (idle) clients can be accommodated by the protocol. The barrier comes when all the (near realtime) data cannot be transmitted in the time available. The 'width' of the signal is set at the AP (typically 20Mhz) and all stations talk in turn within that fixed channel width.

 

[sebastiantombs]

I'm not confusing digital with analog. An RF signal, the carrier, is an analog signal. It is modulated digitally, but the carrier is still present. You are confusing wire transmission, where the cable serves as the carrier, with RF transmission.

 

[Steve Howard]

I'm not confusing digital with analog. An RF signal, the carrier, is an analog signal. It is modulated digitally, but the carrier is still present. You are confusing wire transmission, where the cable serves as the carrier, with RF transmission.

You are wrong, for the reasons stated, but I'm not going to get into a debate here. Maybe read up on 802.11 protocols and specifically TDMA to see how it works. "video is a very wide signal" is nonsense in the context of a digital stream (its just 1s and 0s) and nothing 'overlaps'.

 

[sebastiantombs]

Bottom line, no matter how you state it, is that there is too much data on the WiFi channel. Period, end of story. WiFi cameras are nice consumer toys but not meant for actual surveillance use. Buy some 5E or better cable and get it over with.

 

[Steve Howard]

Bottom line, no matter how you state it, is that there is too much data on the WiFi channel. Period, end of story. WiFi cameras are nice consumer toys but not meant for actual surveillance use. Buy some 5E or better cable and get it over with.

100% agreed on that much.

 

[sebastiantombs]

You also might want to have a look at RF signals and exactly how noisy digital signals are, They generate so many harmonics that they can make lots of other devices not work as well not to mention desensitize the receivers, on both end, in this type of situation.

 

[SouthernYankee]

A while back I ran a Camera wifi test at my house. A separate camera only 2.4GHZ wifi network, separate access point, different SSID, different channel. I could support only 3 2mp cameras at 15FPS. When i went to 4 cameras the network became unstable, with retries. A camera network is under constant load. There are no peaks and valleys in the traffic, so any attempt to retry will cause the network to overload.

The only thing you can try is multiple access wifi points, with different SSID and Different channels. Set the channel with to 20 MHZ. The Access points are hardwired into the network. Also set the FPS down to about 8 or less.

 

[bp2008]

In this case I don't think any camera setting is going to matter because the wifi connectivity is poor even with the cameras not streaming any video.

 

[Steve Howard]

A while back I ran a Camera wifi test at my house. A separate camera only 2.4GHZ wifi network, separate access point, different SSID, different channel. I could support only 3 2mp cameras at 15FPS. When i went to 4 cameras the network became unstable, with retries. A camera network is under constant load. There are no peaks and valleys in the traffic, so any attempt to retry will cause the network to overload.

The only thing you can try is multiple access wifi points, with different SSID and Different channels. Set the channel with to 20 MHZ. The Access points are hardwired into the network. Also set the FPS down to about 8 or less.

This is really useful to get some idea of likely limits - many thanks!