Recent online gaming ping spikes when streaming Netflix

[Ian72]

I've had the exact same issues since December and have been trying to get Bt to acknowledge the problem for months.

I've posted about this on other threads before and I've seen this article and we may finally be getting somewhere and I thought I'd link it for anyone who hasn't seen it.

https://www.ispreview.co.uk/index.php/2019/08/customers-of-uk-isp-bt-see-multiplayer-lag-spikes-duri...

[matthewuncle]

This is great. 

We should all tweet a link to bt.

[lolowalsh]

Back to square 1 with BT. Ping spikes when network is idle are back again after 3 weeks of it being fine. Tomorrow I'm calling to cancel my contract.

[EddyM]

I've just recently started experiencing this issue (or rather, recently started experiencing the effects of it enough to realise it's actually an issue), so I'd been trying to troubleshoot it myself before discovering that it's actually a widespread thing.

I'll probably try to do a full separate post with what I've found so far, as I think there might be some other factors (at least in my case) which aren't mentioned here, but for now it would be very useful if anyone else experiencing this issue could help me collect some more data by doing the following:

Do a speedtest at www.speedtest.net, at a time when nothing else is really using your connection (or at least nothing that causes the ping spike issue for you) - so while you've got a stable low ping. Preferably on a computer with a wired connection to your router, but using the speedtest.net app on a phone via a 5GHz WiFi connection with good signal should also be ok.

Then post a screenshot of the result, showing the actual "graph" of the download speed (so not just a link to the result, as that information will be lost and it'll just show the final speed). What I'm mainly looking for is whether the speed starts off immediately at (or near) your full download speed, or starts off at a much lower speed initially then jumps up after a second or two (and their result graph happens to show that pretty well).

Thanks 🙂

[h3x1e]

The ping issue when streaming has nothing to do with Speed, if your speed drops during ping spikes when IDLE, then it's a totaly different issue.

[EddyM]

I know it's nothing to do with speed (as in low overall download or upload speeds), that's not what I'm saying at all. I didn't say anything about speed dropping, or anything about ping spikes while idle.

[h3x1e]

So can you explain in more detail what your tests are trying to acheive? I guess im not understanding?

[EddyM]

Well I was planning to do more of a full post for that, but that will take me longer to collect my thoughts (and evidence) together etc, and I was hoping to have some confirmation as to whether others are seeing the same thing as me or not before I start saying that it's part of this issue when it might not be (if it's not, then my connection also has another issue, but right now I think it most likely is related to this).

Basically what I'm seeing on my connection (and have been for a few months now, before I discovered this high ping issue being caused by Netflix on a new Fire TV Stick we got last week) is that any download which would normally be able to max out the connection (i.e. no bandwidth limitations on the remote end) will initially start off at somewhere between 10-20mbps, then jump up to the full 60-70mbps that the connection is capable of after a second or two. And, as it now turns out, that also causes this same sort of ping spike at that point. The download will continue at full speed (and ping reasonably low, perhaps a bit higher than idle, but no massive spikes), but if it's stopped or paused and then resumed, it will start off at the lower speed (and cause the ping spike again), even if it's only been paused for a couple of seconds.

I initially thought (mostly due to other posts mentioning Netflix being given priority by BT etc) that Netflix was being allowed to bypass this and consume all of the connection's bandwidth, not leaving any for anything else. But based on further testing, I now think it makes more sense that Netflix is also being affected by this issue, and that's more likely the cause of the problem.

So my current theory (although I don't have any way of directly testing it using my current network setup, as I'd need a way to directly monitor the instantaneous bandwidth usage of the Fire TV Stick) is that when Netflix tries to download some data (as we know it does so in bursts while you're watching something), it runs into this bandwidth restriction as it was previously idle (for at least a few seconds) and causes the lag spike.

So the shape of the graph shown on the results page of speedtest.net is a good way of seeing whether that is happening or not (I'm not at my main computer right now and unfortunately don't have any screenshots saved, but I know that on a Plusnet connection which isn't having the issue at all, the download test starts pretty much immediately at full speed so it's just a straight line going across rather than ramping up).

Hope that makes sense.

[h3x1e]

That makes sense yeah, and this is why I never use Netflix as an example because I ALWAYS expect Netflix to cause a spike in latancy because it first burst downloads the first 5 mins (example) of a show say at full (available) remaining bandwidth (if you have 4MB/s throughput and someone is using 1MB/s of the connection it'll bust 3MB/s for a minute or two) and cause an expected ping spike (possibly). That's kinda not what the issue is though, and it's really do do with the time AFTER that burst has happened, where there is still load on the connection but FAR from your maximum throughput value eg. using 1MB/s of your 4MB/s connection  throughput. Basically the remaining 3MB/s of throughput should be way more than enough for a game to maintain constant low ping.

This makes it more likley it's a traffic shaping issue or faulty equipment at the exchange or deep network level.

I can actually give visual graphs of ping while these two things are happening, both burst download and the steady download of the rest of the show / whatever stream on twitch or w/e im watching.

You can find my thread ( HERE ) . There's a screenshot there of a twitch stream (forgive my amazing paint skills) which I think shows the issue visually.

[EddyM]

Either you're still misunderstanding me slightly, or I'm missing something, but are you saying that Netflix only bursts at the start of playback and then moves to a steady download speed after that? Because in all my testing so far, that hasn't been the case at all - it does do a larger burst at the start, but then after that cycles between nothing for several seconds and then a sudden burst of data (exactly how much data and the interval between bursts seems to vary between platforms though - I can barely get streaming Netflix on a laptop to cause a noticeable issue here at all, but on the Fire TV Stick it's much more problematic).

But excluding Netflix anyway then, are you saying (based on a quick look at your thread, I haven't read the whole thing yet) that even just Twitch downloading at a steady 0.8MB/s (i.e. 6.4mbit/s), with no bursts from it (or anything else) at all, is also causing the ping spike issue for you?