QOS question

[pbix]

The filtered ping is the ping time subject to a low pass filter. See http://en.wikipedia.org/wiki/Low-pass_filter for details.

The "fair link limit" is the link limit the ACC thinks is needed to avoid congestion. The "link limit" is the current link limit. There are several reasons they could be different. For example the ACC is disabled is one case.

For more details of how the ACC works you can study the source code which can be found at http://www.gargoyle-router.com/gargoyle

But I suggest that you gain some experience before you worry too much about such details.

Your question about 4kbps is important. If the load is less than 4kbps the ACC will do nothing so minRTT will not be controlled. At this time the only way to change this is to recompile the controller (qosmon).

Now here are some questions from my end.

Tell me why you think your class load is less than 4kbps? Are you correctly calculating the load?

I am concerned that you entered your own ping limit manually. What limit did you enter? What did the ACC calculate as the proper ping limit and why did you change it?

What ping target did you select and why? Please describe your WAN link and how you are connected to the internet.

What is your native language?
What is your router?
What is your WAN link type?

[antony84]

Ok, i will try to explain better my situation.
I'm italian, and i use a wimax connection from linkem operator.
I have to use their router Huawaei HES-319M for wimax connection.
I set on it DMZ server, that is my tp-link1043nd with gargoyle 1.5.4.
I have tried to set hes-319m in bridge mode, but i don't know how can i set my gargoyle to work with this configuration, because i cannot use pppoe connection.
At the moment, i set gargoyle wan to connect to HES-319m, that use your own nat to connect to internet. I configured wan in gargoyle as wired static ip.
All seems work ok.
I have a qos class that require less than 4kbps, but need low latency. I'm sure that load is less than 4kbps. I see it by iftop, and by ACC monitor too. The load is less than 2Kbps.
About ping limit, my best ping at free bandwidth is 115ms. I set it to 115 because the gargoyle default is 85ms.

Before i recompile qosmon for get activation of classes with less than 4Kbps, i would know how MINRTT mode works. Can you explain please?

[pbix]

You cannot use PPPoE with WiMax connections. Your setup should work Ok if you manually set the ping target.

Gargoyle v1.5.4 does not use 85ms as the default for the ping limit. It measures the correct ping limit to use based on WAN performance. But first you must select an appropriate ping target. What gateway device does the HES-319M get from your ISP? That is probably a good ping target to use.

Your selection of 115ms is too low, it is not possible to maintain the zero load ping times when the link is in use. You should change the ping target only and leave the ping limit in auto mode which lets Gargoyle measure it for you.

What I can tell you about how RTTMode works I have written about in the Wiki. That is the general explanation, if you have a specific question about what is written there I will try and answer for you but I will not repeat the WIki here.

You must establish what the link load of your class will be. You said it is less than 2kbps. Please change this answer to "it is more than ?kbps". Tell me more about this traffic. It is not gaming traffic. What is this traffic used for?

[antony84]

I have selected my ping target. It is my ISP gateway.
But this class is never active, because it never load more of 2kbps.
The traffic is generated by my custom service (i'm a java developer). I would not explain here what it is and what it is used for, but it is sure that it load less than 4kbps.
It is important that RTT for this service is as low as possible.
For this reason, i would find a setting for prioritized this traffic indipendently from bandwidth.

I have checked for other open firmware, and i think this is the behavior of "Exempt" class of the ddwrt qos (from their wiki: Use extremely sparingly for low bandwidth traffic that needs to avoid any delay).

But i would a lot continue to use gargoyle firmware.

I read about qdisc, and i think that what i looking for is qdisc PRIO. What kind of qdisc is used in Gargoyle qos?

[pbix]

Gargoyle uses HFSC + ESFQ in its Qdisc.

DD-WRT cannot maintain a low RTT on a WiMAX link and "EXEMPT" class will not help you either. But you can try DD-WRT if you have time to experiment and see for yourself. In my testing DD-WRT QoS does not actually function, the situation there is very confusing for users.

In MinRTT mode Gargoyle will control your ping times to the MinRTT ping limit. In ACTIVE mode ping times are controlled to a higher limit. When MinRTT mode is active then bandwidth will suffer around a 30% drop in throughput but RTT is minimized. Gargoyle swtiches in and out of MinRTT mode to maximize throughput when possible.

You can make a small change in the source code and compile qosmon so that is always stays in MinRTT mode but then your performance will always suffer.

[antony84]

Gargoyle uses HFSC + ESFQ in its Qdisc.

Ok, then if i want to prioritize, for example, dns requests (port 53), how can i do it?

[antony84]

The only way is allocate a minimum bandwidth for port 53? I think an option for prioritizing low-bandwidth traffic is needed. I think it is the only option that is missing in gargoyle.

[Statix]

Does the MinRTT class flag have any effect if ACC (Active Congestion Control) is disabled?

I read the wiki guide explaining Minimize RTT, but I'm still a bit confused as to how it works and when it takes effect. The write-up seemed to imply that MinRTT only works when used in conjuction with ACC.

Thank you very much for any clarification you can provide.

[pbix]

I edited the QoS wiki guide to clarify this point.