QOS question

[antony84]

Hi, i'm italian, so excuse me before for my bad english. I hope it is understandable.
I read documentation about QOS, but i have some doubts.
Suppose i have two classes, "gaming" and "normal", where gaming has minimum bw.

First question regards packet prioritization when link is not at capacity in upload qos. What happens when link is not satured and both classes gaming and normal have to sent packets? We have two queue, so what is the meccanism for sending packets? Which packets of wich queue are sent?
I think it would be perfect if the same meccanism is implemented even when link is not a capacity.
If i understnad good, this is the "Weighted round robin" meccanism.

Second question is for download qos. I don't understand how ACC can reduce wan utilizaztion.
I think the ISP router, at capacity, send to us all available packets at maximum transfer rate, how can gargoyle tell ISP to reduce throughput?

I'm a bit confused.

[tals]

I believe acc works by stopping the router physically being able to download beyond the limit that it internally sets which stops the line being congested.

Have you had a look at the QOS Wiki

http://www.gargoyle-router.com/wiki/doku.php?id=qos

Queries re QOS are probably best placed in the QOS forum.

Tals

p.s however having been a user who was struggling to have a setup where I can game and the family can stream I can say it does work! I set my classes per person as much because I can then see how much each person downloads at a glance

[antony84]

Hi, in the documentation this is not explained. I would know as tecnically this can happens.

Can some moderator move the thread in the right section?

[pbix]

Regarding question 1, well it does not compute really. If two class have packets waiting then by definition the link is at capacity and QoS works as described in the Wiki.

At capacity mean the link is not waiting for work to do. If you walk into the bank and there is even one person in front of you in line you know the teller is working at her capacity.

Regarding your second question you have to understand a little bit about how the internet works. Lets reverse your question and talk about the uplink. Your computer is connected to the router by a 1Gbps ethernet link. So if you E-Mail a large video to your Mother, how does your router slow down your computer so that data can flow out over your much slower WAN link?

Its a complete bi-directional problem and it is solved on the downlink side in the exact same way it is solved on the uplink side. That is by packet dropping. See "Common Myths" at the bottom of http://www.gargoyle-router.com/wiki/doku.php?id=qos

[pbix]

Regarding question 1, well it does not compute really. If two class have packets waiting then by definition the link is at capacity and QoS works as described in the Wiki.

At capacity mean the link is not waiting for work to do. If you walk into the bank and there is even one person in front of you in line you know the teller is working at her capacity.

Regarding your second question you have to understand a little bit about how the internet works. Lets reverse your question and talk about the uplink. Your computer is connected to the router by a 1Gbps ethernet link. So if you E-Mail a large video to your Mother, how does your router slow down your computer so that data can flow out over your much slower WAN link?

Its a complete bi-directional problem and it is solved on the downlink side in the exact same way it is solved on the uplink side. That is by packet dropping. See "Common Myths" at the bottom of http://www.gargoyle-router.com/wiki/doku.php?id=qos

[antony84]

Thanks for answer.
Respect question one, i think my question is not clear. I speak about packet priority, indipendently capacity or not capacity link.
I would be an example. Suppose my capacity link is 200 KB/s, that is 1600Kbps.
If my classes send data for 190KB contemporaneously, first 180KB are packets from normal class, and the last 10KB of data are gaming packets.
So, link is not at capacity, but gaming packets in this case have to wait that normal packets are send prior. This not affect minimum bandwith, but gaming packet are not prioritized.

Respect second question, ok, gargoyle reduce throughput by packet dropping. Why does not write explicitly in the wiki?
But i think obviously that it will work only if gargoyle router is the last router before ISP. If i use gargoyle router as DMZ router behind an other router (such as my wimax router), the download qos will not work. While i think qos upload will work ok.
It is right?

[pbix]

Regarding one, if your link is 200kB/sec and you are only sending 190KB/sec then no packets are ever waiting. Every time a packet arrives in the router the link is idling and can immediately accept it for transmission. Priority only has meaning if your link is saturated at 200kB/sec and packets are being queued, waiting on the interface to become available to send them.

Think of your bath tub. If the drain can accept 200 gallons per minute there will never be any water in the tub until you are able to add more than 200 gallons a minute to it. At 190 GPM no water is waiting to go out the drain.

Your second statement is also not correct. It does not matter how many routers are involved or where they are. It only matters that Gargoyle is the one that gets to decide which packets are dropped. When the active congestion controller is used you should use a ping target on the ISP side of the link though. If there is any intervening routers then you will need to manually enter a target IP. If you do the ACC guarantees that Gargoyle gets to decide which packets are dropped.

[antony84]

Regarding one. Ok, if we think relying on minimum bandwidth of my service needs, this reasoning is exact.
But, speak about services do not need a special bandwidth for work good, but only need less latency possible.
As you know better than me, only one package can be sent at the same time over phisical link. So, indipendently capacity or not, i would my priority packets are sent before of each other. But, if there are f.e. 200 packets of normal class and immediately after they 20 packets from gamimg class at the same time... my 20 packets have to wait the time x for phisical layer send 200 packets. Now, i don't know how much is time x, but in any case, it is a latency time for my 20 gaming packets. Is it not true?

Regarding two. Ok, i understand your point of view. If my gargoyle drop packets, the normal classs connections reduce their speed, indipendently where is my gargoyle router. It is ok.
So, now, i would understand better how ACC works.
I have a class that loads less than 4Kbps but need very low latency.
I have a download connection of about 6000 Mbps and 115ms ping at free link.
So, how must i set ACC to work ok? An other question, must i set minRTT for the class?
I do not understand the meaning of "filterd ping" and the differences between "Link Limit" and "Fair Link Limit".

Thanks for your support.

[pbix]

Regarding one, you should set you gaming class minimum bandwidth to a little more than your game needs. Mine is set to 100kbps and my game takes about 80kbps. Then also set MinRTT to true for this one class.

Regarding two. There is usually nothing to configure for the ACC. Just enable it. You may check that your ping target is your ISP's gateway device. If you are using a DSL WAN link I highly recommend bridge mode on your modem and using Gargoyle as you main router. This gives the best performance. If you must have intervening routers between Gargoyle and your ISP then you should manually set the ping target to your ISP's gateway.

If you follow one and two above your gaming packets will never wait for packets in classes with no minimum bandwidth and your ping times will be controlled and low. Gargoyle QoS was built for gaming.

Details of ACC operation are shown on the download qos screen and in the Wiki. Your question is covered there.

[antony84]

Ho pbix, i read the documentation more times. I have set the ping target that not is my gateway. I set my custom ping limit. it seem to works, but i would know what i doing. I would know...if it not is a problem.
I not found the meaning of:
1. Fair Link Limit: The apparent fair download bandwidth limit.
What does it mean? What is the difference with link limit?
2. The round trip time filtered.
But filtered what does it mean? What is the difference with ping?

Exuse me but i read very much, but i don't find these informations in the wiki. I would know how tecnically works ACC. I not found this in the wiki.
Can you explain me, please?

An other things. I have an other class that loads less than 4Kbps but need very low latency. How i can set this class? if it load less than 4kbps, minrtt is useless?

I hope you have a little patience with me.