Does uploading slow down downloads?

spookylukey

I recently set up three wireless IP CCTV cameras (Foscam FI8910W), the video is streamed 24/7 via the router having enabled port forwarding. I can log in to the interface and view the video from anywhere, not just on my local network. This may make it sound like I know what I'm doing but I just followed a step-by-step procedure that was posted on the internet! http://www.networkcameracritic.com/?p=124

I also stream the video at 1fps to a cloud based server where it's recorded so I can review the footage. I can also log in to the cloud based server and view the live stream.

Until recently I only had one camera and my internet speed was fine, I recently added the two other cameras and my internet speeds seem much slower. Downloading stuff on the iplayer (on my phone) seemed to take much longer too.

So, I guess my question is whether the recent slower speed is connected to the fact that I'm now permanently uploading via the IP cameras?

bob_a_builder

In a word -Yes
When downloading each frame/packet (might not be right term) needs to be acknowledged as Good or bad - with all that uploading going on less space/time to slip an Ack in - especially since upload is usually a fraction of download speed

colin79666

Is your PC also wireless? As above in theory yes but not by much provided you have some upload bandwidth left for the SYN and ACK (assuming TCP connections). The issue being with wifi is that the ip cameras could be hogging all the available air time.

Try connecting your PC/laptop with a cable to see if that is the case. If it is you could try getting a wireless access point for the cameras and put it on a channel at the opposite end of the spectrum from your regular wifi.

Another thing you can check is if your router supports QOS (Quality of Service). If it does then prioritise your computers MAC over the cameras.

Quiet_Spark

The above explanation by bob_a_builder is just part of the equation.

Ignoring the natural losses that will occur, the more devices you add the more bandwidth you fractionally lose.

For example, one IP cam connected to a 54G router at a link speed of 54Mbps pretty much equals full throughput. However if you connect two IP cams then each camera will only be able to achieve 27Mbps (ignoring losses).

Add a third camera and it's all divided by three, and so on.




PS

The above doesn't apply just to IP cams, it applies to any device that is connected wirelessly.

spookylukey

Thanks all, it's not essential for me to run all three 24/7 so if it continues to slow things down I can turn two of them off at the switch when not needed. It's a shame there's no way of keeping them powered on (but not capturing video) and then remotely starting to allow the video to stream via the router.

Colin - yes, my PC is wireless. Nothing is attached directly to the router (which is a Sky Hub). SYN, ACK and TCP mean nothing to me though!

S0litaire

Have you tried a speedtest site to see what your speeds are with and without the cameras on?

And to answer your question:

Short answer : Yes
Long answer No with a but...

Short answer : every time a packet of data is send from one device to another the receiving device replies with a Acknowledge signal if every thing is ok. If not it sends an error and asks for the last packet to be sent again. If you are on Wired it's not a big issue, But wireless can have a lot more interference which means more errors so more data needs to be sent.

Long answer : the signal can be sent 1 of 2 ways
TCP and UDP

TCP is set up so every bit of data sent needs to be checked and reach the other side 100% intact! ( it's no good if you're downloading a file and bits go missing!!)

UDP does not care if the receiving end gets everything it just keeps spitting out the data till it's finished. What good is that you may ask? if things go missing that's bad? right?

Well not really! UDP should be used for streaming video and audio. If a bit here or their goes missing the player at the receiving end can usually fill in the missing bits and we hardly notice it. unless it's really bad then you notice it stopping, skipping bits and the image goes funny, that is when storing some of the data in a buffer beforehand helps!

Ideally the cameras should use the UDP to stream the video to your PC then the PC should take care of the upload and web monitoring.

It feels to me that the 3 cameras are just streaming too much data to the wireless hub and it's getting errors causing the network to slow down.

I suggest you use a cable between your PC and the Sky Hub. That will take some of the strain off of the wireless and give the PC a more stable connection. Hopefully it should be enough to get your download speeds back.

StuC75

What type of router do you have? is it b\g or n capable (as these will give higher possible bandwidth)..

if using fixed ip addresses \ router assigned, Some can be set to allow ip addresses to have access at only certain times of the day - i.e. Parental Control to stop access at a certain time... so could help control the traffic going out to the internet..