Congestion Control, A Better Explination...

[SouthernGypsy]

Can someone explain something I have never fully understood about how the Congestion Control sliders work in the DumaOS under the QoS settings...

First off, some background... I have an XR1000v2 with Fiber internet, 1Gb both download and upload and I have two questions though my main question is more general about how this setting works.  The instructions say that 70% is usually a good setting but at 70% my upload and download both get an F every time you run the test using the internal Connection Benchmark made into the DumaOS or on external sites that test buffer-bloat such as www.waveform.com so I followed directions and kept moving it 10, then 5 at a time and finally 1 at a time until I found the point where I always get good numbers and an A or A+ but that happens all the way down at around 18-22% on download and 35-40% on upload when using the DumaOS internal tester, or about 28-30% download and 40-42% upload when tested to an external site like waveform. Which when compared to the 70% recommended as a starting point sounds like it's abnormally low and I'm curious what is causing it. My ISP says the small Nokia modem is JUST an open modem, it just connects us direct to the fiber with zero processing beyond just turning the signal from Cat8 cable from our XR1000v2 into a Fiber Signal. They claim it has no buffer settings, DNS settings, nothing, and that at their office they just pass everything straight through. BTW: I did not mess with the "flower" at all, I just leave it alone. And I do have it set to share excess download and upload bandwidth with other devices. So first question is does those settings seem low to anyone else?

 

Then onto my Main question which is the much more general question.

I do not fully understand how the sliders work, nor is it really explained well anywhere in the documentation and searches online did not turn up an answer...  So using the example situation of let's  say I have 1Gb Down/Up, which is 1000Mbps and an Xbox Series X as my only priority device down at the bottom of the page under Traffic Prioritization. So I set a slider to say 30% which is 300Mbps as 300 is 30% of 1000.

 

So the question which I've never seen an explanation of is; By setting the slider to 70% on a 1Gb connection, are you saying to;

A. Set aside/reserve 30% / 300Mbps for the Xbox, and everything else is free to use the remaining 70% / 700Mbps?

....OR....

B. To allow everything else to only have the 30% / 300Mbps and to reserve all of the remaining 70% / 700Mpbs for the Xbox?

 

I was surprized the manual nor anywhere else that I've found really explains which of those is how the Congestion Control sliders work and am hoping one of the Duma guys can explain it.

 

 

 

 

 

[Netduma Fraser]

There are ? icons on each panel of the interface which provide more information such as:

The percentage you set is the max bandwidth devices have available to them, therefore preventing all your bandwidth being used (which would cause bufferbloat), the left over isn't a reserve or set for any device. However, if you're prioritizing a device this supersedes Congestion Control and can in theory use as much bandwidth as it wants, however as gaming uses very little this isn't detrimental to the overall stability of the network.

[SouthernGypsy]

Ah ha, Thanks. And I have seen/read that image before, it pops up at some point when you click (?) on that page, but it doesn't really make it clear if it's reserving that amount for the priority, leaving the remainder for the priority, or as you said jsut preventing everything from using it...

So thanks, that's one question answered I've been wondering about...  

However, That does brings up another question; So if you have it set to allow it set to "Share Excess Download/Upload Bandwidth with All Devices" under the burger icon in the next frame (Bandwidth Allocation), Doesn't that then defeat the above setting anyway?  or does that ONLY refer to the bandwith (in my example 70%/700Mbps) allowed by the above setting?  [that's another place the menus don't really make it clear what's actually happening]

 

[SouthernGypsy]

3 hours ago, Netduma Fraser said:

 

 

Since you seem to understand it well, do you have any idea why I am having to set my sliders so low to get a good Loaded ping on download/upload?   That sounds very low in comparison to the 70% that's recomended for gaming and other people I have seen who seem to use anything from 60% to 85%. Having to set my download silder at 20% means I'm only letting my devices use 200 out of 1000 Mbps and that feels very low to me.

[Netduma Fraser]

It will only be allocating bandwidth according to the bandwidth you have made available in Congestion Control, so if only 70% has been made available then that's all that can be allocated. If a device has 50% allocation but uses just 10% and another device needs 40% but is only allocated 10% it can take that unused bandwidth and use it for itself. 

Well every network is different so not everyone will find the best results in the top end of the percentages, however, the tests you're using are simulating a busy network, so I'd suggest following this guide: https://support.netduma.com/en/support/solutions/articles/16000074717-how-to-test-your-internet-ping while doing downloads, streams etc to saturate your network then start with a high value for Congestion Control, say 95% check the test, decrease by 10%, check, decrease by 10% etc, until you get to a value that is pretty good and then try 5% either side of that value to see if it can be improved. It's important to note that Download & Upload on Congestion Control don't have to be the same value and that you may have a better experience with differing values. This will give you more real world values.

[SouthernGypsy]

9 hours ago, Netduma Fraser said:

 

 

OK, So I download that program and ran that test. I already knew 15-16% was the best setting I could get for my Download setting, I can go as high as 20% maybe half of the time but will randomly see a spike at 20%, at 16% I rarely see spikes. That's on the internal test in the DumaOS. So I moved the sliders to 25% (I know they can be set differently and usually do because upload can be set higher than download, but for this test I set them the same for simplisity) and performed the test, then moved to 20% and repeated and this was one of the times when it still spikes some at 20%, then moved to 16% which is the highest I can set it and only rarely get spikes and as you can see, it barely moved at all. So this backs up what the Dumas internal tester is saying, though I still don't know why it has to be set so low?

Edit:  Oh, the first set of short spikes in each group is Uploading, the larger set is Downloading, although oddly at 16% the Upload bump becomes larger than the Download bump though still lower than at the previous settings. And just for an outside baseline, if I go into DOS and PING google (8.8.8.8) which is who I used here my ping is always a very reliable 16-17ms when the network is at average useage.