Active Congestion Control additional configuration

[DasMarx]

Hello,

Active Congestion Control works quite good for my line, but has one serious problem. I have an unlimited LTE+DSL connection with a maximum of 70 mbit and a minimum of 2 mbit. As it is not only used by me, it can go as low as 2 mbit and this is where the issue happens.

Ones the line is clogged with users and i get less than the 70 mbit/8 = 8,75mbit, the QOS is not working anymore. If a download is running at that time, the router behaves as if no QOS would be needed at that time.

For me, it would be the best to set the minimum value for Active Congestion Control instead of letting the router calculate it.

Felix

[ericwong]

Make sure you set the correct value for "Total Download Bandwidth:" and also "Total (Upload) Bandwidth:". Active Congestion Control depends on it.

[DasMarx]

Hello Eric,

i do have both values correctly set. My theoretical maximum download is 70 mbit, but it can get as low as 2 mbit in extreme cases, my upload is normaly up to 20 mbit and i set it accordingly.

To be more realistic, ive set the maximum download to 50 mbit as a starting point.

IfThe description states:

"The effective range of this control is between 15% and 100% of the total download bandwidth you entered above."

If my line is below that 15% mark, Active Congestion Control stops working.

The problem is, my minimum download speed can go as low as 2 mbit, which is below that 15% mark of 50 mbit.

[nworbnhoj]

The problem is, my minimum download speed can go as low as 2 mbit, which is below that 15% mark of 50 mbit.

There is a related discussion here
viewtopic.php?f=12&t=7972&p=33791&hilit ... ble#p33780

[ericwong]

1) Can you explain why you say ACC is not working as intended?
How do you know it is not?

If a download is running at that time, the router behaves as if no QOS would be needed at that time.

This is not clear and does not indicate any problem with QoS or ACC.

2) I suspect the problem you have is not related to ACC. It sounds more like you did not configure QoS properly.
The default QoS rules are not likely to fit your use cases.

Read the QoS documentation if you have not.
http://www.gargoyle-router.com/wiki/doku.php?id=qos

[DasMarx]

Ok, let me clear up what is happening.

Lets say, i set up my download speed to be 100 mbit.

Now, ACC will vary that speed in the area of 15 mbit and 100 mbit.
This means, congestion is detected in the area of 15 to 100 mbit.

If congestion is detected at 15 mbit, the ACC will stop working at that point and leave the "Total Bandwidth" at 15 mbit.

No comes the part, where my line is actualy slower than 15 mbit. Lets say 8 mbit.

ACC is now turned off and shown as IDLE, it is not doing any pings to detect if the line is still working.

Image showing ACC working:


ACC is shown as IDLE when the line is crippled to 2 mbit (which is my minimum but lower than 15% of my maximum)


And to clear up what i mean with,
"If a download is running at that time, the router behaves as if no QOS would be needed at that time."

It feels like QOS is not active at such a time.

To copy the description inside QOS:
"Percent bandwidth at capacity is the percentage of the total available bandwidth that should be allocated to this class when all available bandwidth is being used."

My assumption at this point is:
1. The router reads a value of X mbit
2. X mbit is below the current maximum Y
3. This yields to => NO QOS needed at that time
4. Y is set by ACC to a point where it reaches 15% of "Total Download Bandwidth:" Z
5. Z is whatever the user would insert in that field.

Correct me here, if im wrong with my assumption of how QOS works when it is below the current maximum.

What would help is the value of ACC where is goes to IDLE, if that would be a fixed number or a setable percentage, the problem would not occure.

[Lantis]

This is really an issue with your setup, not ACC
It isn't designed to handle such a variation.

As was linked previously, you could use a hacky workaround to reset your maxspeed and certain times of the day.

Thats all, unless you want to reprogram the ACC module yourself.

Here's a thread where someone used a script to modify a QOS class values. The same logic can be applied to modifying your max speed.
viewtopic.php?f=13&t=8117&p=34455&hilit=Qos+cron#p34455

[DasMarx]

Thanks for the information so far.

I know it is an edge case and normal lines do not behave like this. The Problem with my line is the LTE part, which might be not present at all.

I already followed the tip to reduce my speed at some time of the day. Setting the maximum download to 50 mbit in the morning and 30 in the evening.

I was just hoping, that the calculation could be done on a mbit level and not on a % level.


https://github.com/ericpaulbishop/gargo ... on.c#L1046
//This limit should be the same as the dynamic range or we could get stuck
//in the IDLE state.
if (dbw_fil < 0.15 * DBW_UL) break;


https://github.com/ericpaulbishop/gargo ... on.c#L1137
//When the downlink falls below 10% utilization we turn off the pinger.
if (dbw_fil < 0.1 * DBW_UL) qstate=QMON_IDLE;

These two values seem to be the problem. On my understanding it is not rewriting the whole stuff, just the relevant part regarding the lower limit, where the state switches to QMON_IDLE.

[Lantis]

You are probably correct but I'll be the first to admit to not understanding the code behind the QOS feature. I've never had time to dig into it.

If it's just changing those values you really should give it a go.

[ericwong]

First, I must say I won't be commenting on codes because I can't understand it.
Second, I never investigate or even look at ACC the way you are trying to, i.e. I never test if ACC is working as intended or not. The only thing I have observed recently is if I have the Download bandwidth set much lower than my true download bandwidth, ACC will throttle my internet to whatever Download bandwidth is manually entered. This is why my first post ask you to check your double check Download bandwidth value.

Re: DasMarx, I believe Lantis means you can try change those values and compile your own ROM and see how it perform.

The ACC configuration page on the router says "adjusting the link speed to the highest speed possible which will maintain proper QoS function". This means the sole purpose of ACC is to make sure your QoS rules works as intended, i.e. whatever traffic you have set to prioritize have higher priority. If it can do this, I would say ACC is working as intended. I won't actually be bothered by the numbers shown.

Afterall, true bandwidth is complicated and hard to measure. I use 100M Optus cable internet here and speedtest shows that I can reach near max bandwidth during peak hours but if I test using overseas speedtest servers, even during offpeak hours, I typically only get less than 10Mbps (more like 1-2Mbps) depending which country I pick.

1) Your screenshot shows some value in link speed. I suppose you take the screenshot while downloading something?

2) You said you have "LTE+DSL connection". Do you mean you have a dual wan modem/router there? If so, measuring your true bandwidth will be even more problematic. For Openwrt multi-wan package, you don't get 1+1=2 for single stream download. Your device will be diverted to either connection depending which connection is faster. If not, how does your "LTE+DSL connection" work?

3) Did you actually try testing your LTE and DSL connection separately at your peak/off-peak hours? Maybe your slow speed is due to your dual wan modem not distributing the load correctly? Or how did you test your connection speed? Speedtest.com with closest servers?

For Optus cable connections, slow (2Mbps) download speed during peak hours have resulted in hundreds of customers complaining at this thread https://forums.whirlpool.net.au/forum-r ... ?t=1501676

I would assume your ISP would have attracted similar attention/complains if it drops so badly during peak time. It appears to me the bigger problem is your ISP not providing sufficient bandwdith

4) In my opinion, to truly test if your ACC/QoS is working, you would have to run many many tests with ACC/QoS on and off to compare the download speed, i.e. you need to run multiple downloads in parallel which falls into different QoS rules and see if their respective bandwidth are prioritized as you have configured. Btw, use the Connection List page to check if the connection is picked up and classified into the QoS rule you specified.

Your screenshots didn't actually show that. Though it also shows you only have 2 classes active, does that mean you have two download streams that fall into two different QoS rule? What is their trasfer speed with/without QoS and ACC?

5) I assume your tests is done over ethernet and not Wi-Fi? because Wi-Fi is not likely to provide the full bandwidth of your connection, especially during peak hours due to interference.

Just remember the purpose of ACC is to make QoS work