Question - Active Congestion Control

[Trailblazer]

I think I've found a problem and I hope it is the cause of what I've been experiencing. I've been having slowdowns on just about any firmware. I used to think that RC5 didn't have them, then I thought that I needed to do a 30/30/30 reset (that did seem to help a bit), but no matter what firmware I load any more, I have a slowdown (until reboot). By slowdown, I mean my 20Mb link can get as low as 1-5Mb or so according to speedtest.net.

I use QOS download and upload with the Active Congestion Control enabled on the QOS Download. Here's what I noticed tonight during a slowdown:



Why would this ever go down to ~5Mb when I have it set as:
Total (Download) Bandwidth: 22000 kbit/s ?

I tried disabling Active Congestion Control. Speed was not restored. I disabled QOS (download) and speed was restored. Router is WZR-HP-G300NH running 1.4.5, there are 8 users going through the router, 1 connected wirelessly and the CPU load is 0.00 / 0.02 / 0.00 (1/5/15 minutes).

I am happy to do whatever testing is needed. This is production, so I can really only do it at night for the most part. I really, really want to get this solved. It's been going on for months. Thanks!

Help Pbix!

[pbix]

The screen shot you posted shows the link limit at 5.3Mbps and the load at 2Mbps. So at the moment of this screen shot the ACC is not limiting your speed since the limit is set at more than twice the load. The limit is 5Mbps because at some point the ping times were higher than 85ms so the limit was reduced.

The ACC will not increase the link limit until the load indicates that it would be beneficial to do so.

Can you post a screenshot that shows the load is the same as the link limit and the ping time is acceptable? That would show that the router is in fact limiting your download speed.

When the ACC is disable it automatically sets the link limit to the maximum. Since you indicated that disabling ACC has no effect why is the subject of this post indicating you think the ACC is related to this issue?

How can you tell that disabling QoS has any effect on your download speed? What do you use to measure the speed before and after disabling?

[Trailblazer]

Hi pbix,
Thanks for replying. You're right, I shouldn't be saying that the ACC is responsible. I did say that I thought it was in my setup and if I didn't mention it before, I admit that I have no idea why it does what it does. Your explanation helped, thanks for that. I really like the QOS in this firmware. It is the main reason I use it and I want to get my setup correct so that I can enjoy the hassle-free network admin that it offers. Thanks for all your efforts, BTW. I really do appreciate what you and Eric and others have done.

My link is 20Mbps Down/ 1Mbps Up. The link is regularly slow(once a day, at least) and when I check traffic, there is none to very little. Then I use speedtest.net with a server that gives me 20Mb when things are working right. In this particular instance, speedtest showed around 5Mb. I got the bright idea to check the ACC because I can see realtime link load. I was surprised to see the link limit set to ~5Mb.

I hear that you are saying that the ping to the default 'ping site' is over 85ms so the ACC lowers the link speed in order to meet the QOS requirements. Should I simply use the new feature to specify my own ping target, one that is 'closer' and/or lower?

I have no idea why, but when I disabled the ACC, speed using speedtest.net (to the same above-mentioned server) was not restored. I did not reboot, I only applied changes. When I turned off QOS download, then applied changes, speed to the same server was restored.

I re-enabled everything and I'll watch for the situation you mention for the screenshot. How long before the link limit is restored after a high ping? I did a little testing and I didn't see it restored in the 5 minutes I watched it (after load was completely removed).

Thanks! for your help!

[pbix]

The speed test you are using is pretty short and is not appropriate to do what you are trying to do. It is not of long enough in duration. The ACC moves the link limit up slowly until ping times start to increase. If you want to test download Ubuntu http://www.ubuntu.com/download/ubuntu/download. The ubuntu.iso is a large enough file so you can see the ACC operate.

While the link is saturated and the ACC pings are at the target times take a screen shot and post that.

Even though your ISP told you you have a 22Mbps downlink we are going to find that it 22Mbps only for brief periods if at all. Then they throttle you, get overloaded or whatever and you no longer get the 22Mbps. This is typical anyway.

Even with your below explanation I cannot understand how you know the link has 'slowed down" as you complain. Are you just randomly running the speedtest during the day, every day? I would think something else would be the trigger for you to run speedtest.

[Trailblazer]

Hi pbix,
I know the link has slowed down because a download is going much slower than expected or a video isn't playing properly or my browser is loading commonly used web pages slowly. Then I go through the testing thing which includes running speedtest, using at least 2 servers.

A reboot always restores the speed. I'm curious how the link could have gotten down to 5Mb and stayed there as was showed in the original screenshot.

When I did the testing you asked, the link limit went up and down with the ping as expected. Here are the results:







Is this what you were looking for? It's working fine in these. It was down at 10Mb at one point, but speed was restored (link limit) when the load went down.

[tals]

If you disable QOS do you experience a slowdowns like this at various times, ie don't just turn it off at issue times keep it off, do you then see the same slow down.

I had a similar issue and it turned out my line was actually coming down in speed and all the acc was demonstrating was it was having to cope with this slow down. My line was adsl though.

[pbix]

Trailblazer,

It seems that your ACC is working correctly and that there is no "slowdown" in your downlink, at least in the screenshots you showed me.

More than likely your ISP is throttling your downlink speed at some point and the ACC is only coping with this situation. As to why your ISP is throttling you I cannot say. It may be that when you reboot your router your get a new IP address from you ISP which is not throttled but I cannot say for sure.

Anyway I cannot see any issue with Gargoyle QoS. The fact that your videos are slow is not proof that Gargoyle is at fault. The most likely situation is that your ISP slowed your link temporarily for whatever reason. If you can show something that would demonstrate otherwise please post again.

[mix]

What ISP are you using Trailblazer?

[Trailblazer]

What ISP are you using Trailblazer?

I am using Emery Telcom. It is a cable modem. I know you guys think it's my ISP and that may very well have something to do with it, however I believe it is actually an expected outcome of using the ACC and here's why---->

I re-read the developers comments and I now think I understand that it is working exactly as intended:

The ACC will not increase the link limit until the load indicates that it would be beneficial to do so.

When I came to the router tonight, this was where it was at. I had watched it slowly go down all day.



A SpeedTest confirmed what the ACC listed as the Link Limit.



I then saturated the link and watched the Link Limit rise to what you see here.



I killed all the downloads. The Link Limit stayed where it was and again it was verified by a SpeedTest.



All of this testing was performed in about 10 minutes and without any reboots of router or cable modem or turning on/off of ACC or QOS. I've done my best to be methodical and clear. Any ideas or corrections are welcome.

I think I now understand the ACC more. I think the Link Limit goes down because the ACC sees unacceptable ping times (which I have seen in my testing and may be the result of throttling by the ISP). It doesn't go back up until it sees an advantage to do so (the link is saturated and it needs more bandwidth and only if ping times stay in the acceptable range?). I have changed the subject of my thread to being a question rather than a problem.

This firmware makes my life so much easier through the use of QOS to keep users I cannot otherwise control from hogging bandwidth. Once again, thanks pbix for an excellent implementation of QOS!

[tals]

Just wondering, if you ping the target what response is it giving you, you could set a higher value of the ping in the acc which will make the acc be more tolerant if the throttling by the isp is degrading the ping. You could also try different locations to ping