Lag in gaming while Netflix (and other streaming services) being used

Junk

Junk

Junk

Associate
Joined
13 Feb 2006
Posts
465
Location
UK
Hi Guys,

I anyone else seeing issues where online games are rendered almost unplayable when someone in the house is streaming on Netflix or other similar streaming service?

We have BT FTTC (we're in a rural area) of 10 up and 60 down. Using the HomeHub 2. Wired network for gaming PCs.

The internet seems to think it's a common issue with a few providers and not exclusive to the UK either.

Anyone found any solutions to this?

Thanks

Junk.
 
maybe the kind of traffic you get when you stream media is prioritised.

like on routers where you can give priority to packets on specific ports etc, some of the dlink routers used to have a thing called game boost or something like that which sort of set it up for you for gaming.

maybe its something isps do to cut on the buffering when someone else is downloading/we browsing or whatever in your household
 
Junk said:
Hi Guys,

I anyone else seeing issues where online games are rendered almost unplayable when someone in the house is streaming on Netflix or other similar streaming service?

We have BT FTTC (we're in a rural area) of 10 up and 60 down. Using the HomeHub 2. Wired network for gaming PCs.

The internet seems to think it's a common issue with a few providers and not exclusive to the UK either.

Anyone found any solutions to this?

Thanks

Junk.
Click to expand...

Yes it's a known issue. Started around December 2018 and slowly more and more users realised this was happening with BT. No-one from BT will confirm what the exact issue is. Before my contract ended I managed to complain enough that they "fixed" it. What I realised through testing was they completely changed the routing of my internet access. I'm not sure if they are using some kind of traffic shaping to roll out more video content or if certain routes are just completely overloaded. The forum post of complaints is still on the 1st page of their forum with no fix in sight.

Depending on your contract length. Sign up to the forum and request support from one of the mods. They might be able to fix the issue with putting you on a different route.
 
Unfortunately, I don't think there's that much you can do, which will yield much of an improvement.

The problem is most likely that because your gaming traffic (very small packet sizes <64 - 256 bytes>) are being mixed with large packets from Netflix or other stuff (1500 byte packets)

The nature of Netflix traffic, is it's very bursty - it downloads big chunks at close to full speed, then stops completely. This is going to cause big problems for gaming traffic, because your steady 128-160Kbps of 64 byte packets, are going to get held up in the buffers of your router, when those buffers are also full of Netflix packets, so you probably will see packet loss, higher latency and jitter.

You might be able to buy a more expensive/better router and configure ingress queueing/rate limiting, to 'slow down' Netflix traffic and prevent buffer starvation, but it might take a bit of research and lots of tweaking to find something that does work.
 
Screeeech said:
Unfortunately, I don't think there's that much you can do, which will yield much of an improvement.

The problem is most likely that because your gaming traffic (very small packet sizes <64 - 256 bytes>) are being mixed with large packets from Netflix or other stuff (1500 byte packets)

The nature of Netflix traffic, is it's very bursty - it downloads big chunks at close to full speed, then stops completely. This is going to cause big problems for gaming traffic, because your steady 128-160Kbps of 64 byte packets, are going to get held up in the buffers of your router, when those buffers are also full of Netflix packets, so you probably will see packet loss, higher latency and jitter.

You might be able to buy a more expensive/better router and configure ingress queueing/rate limiting, to 'slow down' Netflix traffic and prevent buffer starvation, but it might take a bit of research and lots of tweaking to find something that does work.
Click to expand...

10 up and 60 down is more than enough for a netflix stream + gaming at the sametime. A good router with QoS/Bufferbloat protection will help but it's not a fix for the actual cause from the BT network. @Junk in the past were you able to play with a video stream on in the background?
 
Having used one myself I can recommend the Netgear Nighthawk XR500.

The Duma OS allows you to tweak and prioritize all your internet traffic.

But they are expensive and that's assuming BT allow you to use your own router.
 
ColdAsIce said:
10 up and 60 down is more than enough for a netflix stream + gaming at the sametime. A good router with QoS/Bufferbloat protection will help but it's not a fix for the actual cause from the BT network.
Click to expand...

Well it depends, on a whole number of factors.

If my download speed is 60Mbps, but when I open Netflix - it tries to send data towards me at the maximum rate (because it's TCP, by it's very nature is very bursty) it will temporarily fill the buffers - only for a second or two, then back off and slow down. If I'm playing a game at the same time (steady stream of UDP packets) - I'm going to see packet loss and jitter, because congestion is occurring.

The actual packet loss/jitter might be caused at the BT end (on the BNG) due to it hitting the max profile speed (60Mbps) in which case anything above that will be randomly dropped, but overall - the problem is most likely exactly what I said it was - mixing sensitive gaming traffic, alongside big heavy data packets.

Almost all ISPs 'police' customer connections on the BNG, so this problem isn't common to BT - you'll run into the same issue on just about any ISP.

As I say, you might be able to rate-limit netflix down using a decent router, but again, it depends on a whole number of factors.
 
Screeeech said:
Well it depends, on a whole number of factors.

If my download speed is 60Mbps, but when I open Netflix - it tries to send data towards me at the maximum rate (because it's TCP, by it's very nature is very bursty) it will temporarily fill the buffers - only for a second or two, then back off and slow down. If I'm playing a game at the same time (steady stream of UDP packets) - I'm going to see packet loss and jitter, because congestion is occurring.

The actual packet loss/jitter might be caused at the BT end (on the BNG) due to it hitting the max profile speed (60Mbps) in which case anything above that will be randomly dropped, but overall - the problem is most likely exactly what I said it was - mixing sensitive gaming traffic, alongside big heavy data packets.

Almost all ISPs 'police' customer connections on the BNG, so this problem isn't common to BT - you'll run into the same issue on just about any ISP.

As I say, you might be able to rate-limit netflix down using a decent router, but again, it depends on a whole number of factors.
Click to expand...

As much as these are all factors. There are 100s if not 1000s of customers that were happily streaming netflix, youtube, nowtv etc etc on their connection while gaming without a single issue and then over night something changed and they cannot load a single video stream without huge lag spikes. That is something taking place on the BT side.

I did many tests with ping plotter etc to monitor the connection. Would ping google and get something like 8-16ms. Simply loaded a single video stream and the ping was spiking all over the place. That was without me loading a game or any other stream. Just one single video stream would cause this. Are you telling me a connection of 10 up and 60 down cannot stream a single video without huge spikes in ping?
 
ColdAsIce said:
10 up and 60 down is more than enough for a netflix stream + gaming at the sametime. A good router with QoS/Bufferbloat protection will help but it's not a fix for the actual cause from the BT network. @Junk in the past were you able to play with a video stream on in the background?
Click to expand...

Yes, it's not always been the case. We've noticed it since last year but it's got a lot worse since the turn of the year. Using Netflix app on the Sky Q box is far worse than a chromecast or on a tablet but it still renders any competetive gaming to be, to turn a phrase, hit and miss. Definately more miss!

i've read the BT forums now and they are admitting hardware issues on their network that are in the progress of being sorted out (they state a couple of months). Oddly we had a local fault maybe 3 weeks ago that resulted in a couple of men periodically sticking out of holes in the road for a day or two - after they fixed our line it was fine again for at least a week then back to abysmal over night when streaming.

@Screeeech that's interesting - so Netflix is 'pushing' the data rather than allowing it to be pulled as needed? that would explain a fair bit. It's such a shame that BT have such simple interfaces on their hubs. You can switch it on / off / reset and that's about it.

One fix i have heard of is to route netflix through the BT Fon external wifi - but i spent two months on the phone getting that switched off i'm kind of embrassed to ask then to switch it on again.
 
It's not restricted to just Netflix either. Test for yourself. Load up twitch, mixer, youtube. Pretty much any video streaming service and you can monitor the spikes to your connection in real time. Download ping plotter and look for yourself.
 
Junk said:
Hi Guys,

I anyone else seeing issues where online games are rendered almost unplayable when someone in the house is streaming on Netflix or other similar streaming service?

We have BT FTTC (we're in a rural area) of 10 up and 60 down. Using the HomeHub 2. Wired network for gaming PCs.

The internet seems to think it's a common issue with a few providers and not exclusive to the UK either.

Anyone found any solutions to this?

Thanks

Junk.
Click to expand...

As mentioned netflix is very 'bursty' so it'll just max out your connection to download chunks rather than running a continuous stream. Only way around this would be some sort of QoS. I also suspect BT will just drop packets instead of trying to queue them.

It doesn't help that it wants to continuously send data back to netflix while you're watching.

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ColdAsIce said:
Are you telling me a connection of 10 up and 60 down cannot stream a single video without huge spikes in ping?
Click to expand...

60Mb isn't really that much nowadays, if I open Netflix my traffic spikes right up to 80-90Mbps for 1-2 seconds, because it's TCP traffic, it'll naturally try and use as much bandwidth as possible (especially if the latency is low) until it hits the ceiling, then slows right down - that's the point where you'll see a ping spike, during bursty periods of congestion. It's not like old fashioned streaming video protocols where you have a steady 5-20Mbps, it comes down in great big lumps.

Junk said:
@Screeeech that's interesting - so Netflix is 'pushing' the data rather than allowing it to be pulled as needed? that would explain a fair bit. It's such a shame that BT have such simple interfaces on their hubs. You can switch it on / off / reset and that's about it.

One fix i have heard of is to route netflix through the BT Fon external wifi - but i spent two months on the phone getting that switched off i'm kind of embrassed to ask then to switch it on again.
Click to expand...

Well, it's TCP - which, when it wants to send data, it will do something called 'windowing' (google tcp windowing) which means your client is immediately going to 'download' a chunk of video, it'll probably do this at the maximum speed of your pipe (unless it's really fast, or it's really laggy) at which point, it'll hit the max rate, and 'window down' to avoid packet loss, or out of order packets, etc. Netflix will probably be doing something (a lot) to deal with TCP issues, but on the whole - that's how it'll work.

Basically, when you watch Netflix - it's not really a video stream in the conventional sense, it's just big chunks of data which are downloaded and reassembled into a video, presumably they do this because it can be encrypted (TCP 443) and is harder to snoop ect.

But honestly - these problems have been coming up again and again since people have played games, and streamed video.
 
Janesy B said:
As mentioned netflix is very 'bursty' so it'll just max out your connection to download chunks rather than running a continuous stream. Only way around this would be some sort of QoS. I also suspect BT will just drop packets instead of trying to queue them.
Click to expand...

Basically this.

BT will just randomly drop anything that exceeds the profile (60Mbps) and they'll taildrop everything else, at which point - they're not going to classify anything, they'll just drop anything over 60Mbps (including those delicate game packets), at which point you'll see lag/packet loss / jitter etc.

What's interesting, when you run Wireshark and watch bandwidth usage, whilst watching a Netflix video, it looks like a file download, rather than an old fashioned video stream... It just tries to download as much as it can as fast as it can, then it stops for 10-20 seconds, then it does it again.
 
Screeeech said:
Basically this.

BT will just randomly drop anything that exceeds the profile (60Mbps) and they'll taildrop everything else, at which point - they're not going to classify anything, they'll just drop anything over 60Mbps (including those delicate game packets), at which point you'll see lag/packet loss / jitter etc.

What's interesting, when you run Wireshark and watch bandwidth usage, whilst watching a Netflix video, it looks like a file download, rather than an old fashioned video stream... It just tries to download as much as it can as fast as it can, then it stops for 10-20 seconds, then it does it again.
Click to expand...

Absolutely agree regarding Netflix but you are focusing solely on Netflix being the issue. This doesn't explain why on the exact same connection (no changes to package / download or upload) that it goes from no lag spike issues to spiking every second or so.

We need junk to post some results from testing to actually paint a nice picture of what is taking place :)

  • Download ping plotter.
  • Run a speed test before using ping plotter so we can see the results of your connection speed currently.
  • ping bbc or google within ping plotter without loading anything at all in the background. No games, no video stream etc. Run this for a few minutes recording results every 0.5 seconds.
  • Load up Netflix and start streaming some video content, again run ping plotter for a few minutes recording results every 0.5 seconds.
  • Close netflix.
  • Copy the test but this time load a video streaming service that is not netflix. Try loading twitch and even lower the quality to 480p and I bet you will see the same spikes across your connection. Even though your bandwidth is no-where near being maxed.
 
Ok, So Update...

First thanks to @ColdAsIce for posting all that - that's exactly what the BT Community asked me
(and others) to do - but i appreciate you trying to help :) . BT were very good about this. Apparently there are 10 different reasons this can happen and they understand the issue well. I think they made recent changes (a year ago ish) before people started getting the probelm and are resolving it fully in due course. In teh mean time they are taking each case and helping where they can.

What BT did for me was monitor for 48 hours and then reduce the amount of bandwidth Netflix is allowed to use to my router (i'm hazarding this is number of connections rather than actual kbps) which allows enough clean bandwidth (again i'm convinced this is connection contention - when accessing the internet you have a fixed number of connections that can go throuigh your router at once before stuff gets clogged - similar concept as database connections / CPU threads but more networky. As part of this Netflix content appears to be consistently coming from a BT CDN (Content Delivery Network) rather than any it fancies.

The end result is that even when netflix is going through Sky Q (the worst offender which seems to always try for 4k content even when TV only 1080p) i get a fairly consistent 30ms ping in Valorant and using ping plotter a very consistent 8 - 12ms to BBC. There are still the occasional spikes but gameplay is generally smooth and nearly as snappy as no netflix being on. It's not perfect but then i wouldnt expect it to be.

So i can play games while the missus watches netflix and now we have to find another subject to bicker about!
 
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