[Q] Adaptive QOS Settings

[Matthew Patrick]

For reference, without QoS/rate-limiting, when my download is saturated, my ping increases to ~50ms from ~10ms (QoS/rate-limiting improves the max ping to ~30ms). When I saturate upload, my ping increases to ~600ms (depending on the router/modem I am using).

So, I choose to only limit my upload, since getting 100% of my download is worth the minimal latency increase.

I think latency during download saturation is ISP dependant, so YMMV.

So u just set the download to your real speedtest result?

 

[Nullity]

So u just set the download to your real speedtest result?

I disable download QoS completely.

If you must input a bandwidth parameter, yeah, you could virtually disable QoS if you were to input a bandwidth that exceeds (by a not a small amount) your measured bandwidth.


Download & upload only practically (technically, from a unnetworked, absolutist "I have data, I need to send data" perspective, only sending can be controlled and receiving is uncontrolled) differ by the inherent latency between TCP's request & response of congestion control.
When your gateway router sends LAN-originating data, if the router is receiving data faster than it can send the data, it will drop packets to let the LAN-sender know to slow-down, which will take just a few milliseconds for the sender to sense congestion, plus a couple milliseconds for the sender to enforce (because some packets are "in-flight") the decreased bitrate, then another couple of milliseconds for the gateway router to actually begin receiving the slowed bitrate it requested.

So... now apply the same logic to downloads, but realize that TCP's congestion avoidance "request, receipt, response, and answer" has to deal with hundreds of milliseconds of internet latency, rather than just a few milliseconds between LAN clients. This means that the global download bitrate needs to have a rate-limited bandwidth ceiling that is low enough to never be exceeded even when multiple (could be hundreds, with bittorrents) senders may exceed your configured bitrate maximum for hundreds of milliseconds before you actually receive the slowed bitrate you requested.

The respected toastman even advises limiting download up to 60% to avoid download saturation.

From a QoS perspective, the internet backbones solve latency problems by the most reliable possible method: never exceed 50% link saturation.

 

[Matthew Patrick]

@Nullity okay. But i want qos so all bandwidth not gonna go to one devices when downloading torrent or games. So. If i just limit download 90% the upload. Than the prob that makes the download decreased when upload saturated gonna go right? Thx

 

[yelo3]

Just a question:
rtAC-56u with firmware 380.58
I've enabled adaptive QOS and set an upload of 0.45 Mb/s
In bandwidth monitor I see it can go up to 0.60 Mb/s
Is this the expected behavior? I thought that upload speed could never exceed the max upload bandwidth setting... Maybe QOS is not working in my case?

 

[RMerlin]

Just a question:
rtAC-56u with firmware 380.58
I've enabled adaptive QOS and set an upload of 0.45 Mb/s
In bandwidth monitor I see it can go up to 0.60 Mb/s
Is this the expected behavior? I thought that upload speed could never exceed the max upload bandwidth setting... Maybe QOS is not working in my case?

If Adaptive QoS works like Traditionnal QoS (I don't know as it's closed source), then it won't limit you unless there's something with a higher priority needing to access the Internet. That value is used to calculate what percentage is allocated to each of the limited clients.

 

[yelo3]

Mmmm OK.
I asked this question because I really can't find the correct setup for my network.

I massively use cloud services, to automatically backup photos and videos. As soon as I take a picture or record a video, my apps will upload it to google photos and microsoft onedrive, so my upload bandwidth can be at full usage for long periods (some hours).

During this period viewing web pages is very very slow and watch streaming services (youtube) is almost impossible, even if my download bandwidth is free.
By reading this thread I've understood the problem: upload is used too much.

So I set up my upload bandwidth to 90% of 0.5 Mb/s, but it seems it does not improve the situation: If I try to run a speedtest I get a ping of 1500-2000 ms and download 0.25 Mb/s (while I can do up to 7Mb/s)

Do you have any suggestions?

Thanks for your help

 

[L&LD]

In your situation, you may need to set it to 80%, 70% or even 50%. Testing more will tell.

 

[Nullity]

Mmmm OK.
I asked this question because I really can't find the correct setup for my network.

I massively use cloud services, to automatically backup photos and videos. As soon as I take a picture or record a video, my apps will upload it to google photos and microsoft onedrive, so my upload bandwidth can be at full usage for long periods (some hours).

During this period viewing web pages is very very slow and watch streaming services (youtube) is almost impossible, even if my download bandwidth is free.
By reading this thread I've understood the problem: upload is used too much.

So I set up my upload bandwidth to 90% of 0.5 Mb/s, but it seems it does not improve the situation: If I try to run a speedtest I get a ping of 1500-2000 ms and download 0.25 Mb/s (while I can do up to 7Mb/s)

Do you have any suggestions?

Thanks for your help

Latency during queue/link saturation is mostly buffering or "bufferbloat". This can be mostly fixed by using a router that supports an AQM like fq_codel or RED. AsusWRT does not currently support codel/fq_codel.

I dunno if Trad QoS can rate-limit individual queues to a specified speed. Try "Limiters"?