This question has come up a few times on the forums but I have yet to see any solutions posted.
Suppose I have a wireless link on which the speed varies between 7 Mbps and 10 Mbps depending on the weather.
At the end of the link I have a routerboard with two computers (on different vlans, or ethernet ports or different IPs, whatever).
Can I set it up so that Computer A gets 100% of the capacity when Computer B is not in use but only 80% of the capacity when Computer B is trying to use the network?
I can't just cap Computer A at 8 Mbps because sometimes that would leave 0 Mbps for Computer B.
I can't cap them both at 7 Mbps because that's 3 Mbps wasted.
Is there a way to specify priority/queues in % instead of bits?
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omidkosari
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Re: Prioritizing Traffic with Unknown Link Capacity
Me too.This question has come up a few times on the forums but I have yet to see any solutions posted.
Re: Prioritizing Traffic with Unknown Link Capacity
This is a difficult task. The way to do this, would be to set limit-at values. This is something that I address directly in my training on QOS (coming up this week - http:///www.butchevans.com/ for details). You could do queue trees something like:
I'm not sure that would address all of your issue, but that's the approach I'd take. It will guarantee speeds of 5M for A and 2M for B (when the link capacity is only 7M), and allow for the higher speed capability
Code: Select all
/queue tree
add name=Total parent=downstream max-limit=10M
add name=download_A limit-at=5M max-limit=10M parent=downstream priority=1
add name=download_B limit-at=2M max-limit=10M parent=downstream priority=2
Re: Prioritizing Traffic with Unknown Link Capacity
I would check the link capacity doing a latency test between the links,
Once you got your latency (about 80 pings over 50ms (assuming your link is able to support a good latency (1-2 ms average))) you can decide to lower the max-limit of your queues accordingly until the latency drops to your desired limit.
I'm not sure this code is correct and i don't know if this will fit your needs, but maybe you got my idea to solve your problem
Code: Select all
:local ipaddress 10.100.0.18
:global latency [ping $ipaddress interval=50ms count=100];
Code: Select all
:local currentmax [/queue tree get GlobalOutQueue max-limit];
:if ($latency < 80) do={/queue tree set GlobalOutQueue max-limit=($currentmax - 1000000);};
Re: Prioritizing Traffic with Unknown Link Capacity
While I agree that the latency test may be a usable approach, it is not, by itself, a good test. This test would fail, for example, if the link was at full 10M capacity and utilization was at that rate as well.
Re: Prioritizing Traffic with Unknown Link Capacity
You could use some variation on:
Just for example. Not fully tested
Code: Select all
:local "tx-total-average";
:local speed 0;
/tool bandwidth-test address=192.168.5.1 user=admin password=**** protocol=tcp duration=4s direction=both do={
:set speed $"tx-total-average";
:if ($"speed" < 9000000 ) do={
/queue tree set [find] max-limit=7000000
}
}
Re: Prioritizing Traffic with Unknown Link Capacity
The problem with doing a speed test is that it would give incorrect results because the link is already in use.
Of course, I can't turn off the users before every test.
The ping solution is decent.
Is that as good as it gets or someone knows something better?
Of course, I can't turn off the users before every test.
The ping solution is decent.
Is that as good as it gets or someone knows something better?
Re: Prioritizing Traffic with Unknown Link Capacity
Not many choices here. The queue structure I showed is really the best approach and it will work for what you want. I only presented the option of the speedtest since we were playing with scripting. 
Re: Prioritizing Traffic with Unknown Link Capacity
I tried "limit-at" in 3.30 but it seems to do nothing at all. Any ideas if it works in older or newer versions?This is a difficult task. The way to do this, would be to set limit-at values. [...]Code: Select all/queue tree add name=Total parent=downstream max-limit=10M add name=download_A limit-at=5M max-limit=10M parent=downstream priority=1 add name=download_B limit-at=2M max-limit=10M parent=downstream priority=2
As for the "max-limit" settings in your queue, what is the point? Am I not going to get the same result if I set max-limit to 30M or nothing at all (if limit-at worked)?
Re: Prioritizing Traffic with Unknown Link Capacity
I tried "limit-at" in 3.30 but it seems to do nothing at all. Any ideas if it works in older or newer versions?This is a difficult task. The way to do this, would be to set limit-at values. [...]
As for the "max-limit" settings in your queue, what is the point? Am I not going to get the same result if I set max-limit to 30M or nothing at all (if limit-at worked)?
Code: Select all
/queue tree
add name=Total parent=downstream max-limit=10M
add name=download_A limit-at=5M max-limit=10M parent=downstream priority=1 packet-mark=comp1
add name=download_B limit-at=2M max-limit=10M parent=downstream priority=2 packet-mark=others
/ip firewall mangle
add chain=forward src-address=10.10.10.10 action=mark-packet new-packet-mark=comp1
add chain=forward dst-address=10.10.10.10 action=mark-packet new-packet-mark=comp1
add chain=forward action=mark-packet new-packet-mark=others
Re: Prioritizing Traffic with Unknown Link Capacity
I already did all the packet marks on my own. Thanks tho.I did not include the full implementation. This is closer to complete.
I think "limit-at" is broken, but, before we address that, a question remains, is "max-limit" needed here at all?
Re: Prioritizing Traffic with Unknown Link Capacity
Needed - maybe not. At least the parent needs to know the total available bandwidth. I just did a test on 3.30 with this exact configuration and it works just right. I don't know what part is not working in your config, or which version you are using, but I do not experience a "broken" limit-at value.
Re: Prioritizing Traffic with Unknown Link Capacity
CRAP! I just saw my error. I have the parents wrong (which is why it isn't working for you). Try THIS one.
In my haste, I made the child queues use the interface as parent instead of the "Total" queue, which is what it is supposed to be. Sorry about that. With THIS config it will work as advertised. 
Code: Select all
/queue tree
add name=Total parent=downstream max-limit=10M
add name=download_A limit-at=5M max-limit=10M parent=Total priority=1 packet-mark=comp1
add name=download_B limit-at=2M max-limit=10M parent=Total priority=2 packet-mark=others
/ip firewall mangle
add chain=forward src-address=10.10.10.10 action=mark-packet new-packet-mark=comp1
add chain=forward dst-address=10.10.10.10 action=mark-packet new-packet-mark=comp1
add chain=forward action=mark-packet new-packet-mark=others
Re: Prioritizing Traffic with Unknown Link Capacity
have anybody played with 'ping-speed'?
also, maybe it's possible to check current link's capacity in scheduler and then correct queue's parameters
also, maybe it's possible to check current link's capacity in scheduler and then correct queue's parameters
Re: Prioritizing Traffic with Unknown Link Capacity
That's one of the combinations I tried yesterday, but it still didn't work.CRAP! I just saw my error. I have the parents wrong (which is why it isn't working for you). Try THIS one.
What is "downstream"? Is that supposed to be the ethernet interface both computers are on?
Re: Prioritizing Traffic with Unknown Link Capacity
Yes, downstream would be the name of an interface. If you have 10M download capability, then downstream would be the side facing the computers. If this is a bridge interface, then we have to adjust the rules and mangles.
Re: Prioritizing Traffic with Unknown Link Capacity
Just tried it again. 100% fail.With THIS config it will work as advertised.
If I run a speed test with 20 threads on one computer, and 1 thread on the other, the one with 20 threads gets 90% + of the link.
If I flip the test locations, again the computer with more threads gets almost all the link.
It's as if the "limit-at" setting gets ignored.
Re: Prioritizing Traffic with Unknown Link Capacity
did u add the passthrough=no on the first 2 mangle rules? Otherwise it will remark everything as "other"
Re: Prioritizing Traffic with Unknown Link Capacity
Yes. I checked and the expected traffic is showing up in the expected queue but limit-at is being ignored.did u add the passthrough=no on the first 2 mangle rules? Otherwise it will remark everything as "other"
Have any of you seen limit-at work recently?
Re: Prioritizing Traffic with Unknown Link Capacity
It has been a while since I first posed this question.Suppose I have a wireless link on which the speed varies between 7 Mbps and 10 Mbps depending on the weather.
At the end of the link I have a routerboard with two computers (on different vlans, or ethernet ports or different IPs, whatever).
Can I set it up so that Computer A gets 100% of the capacity when Computer B is not in use but only 80% of the capacity when Computer B is trying to use the network?
I can't just cap Computer A at 8 Mbps because sometimes that would leave 0 Mbps for Computer B.
I can't cap them both at 7 Mbps because that's 3 Mbps wasted.
Is there a way to specify priority/queues in % instead of bits?
Has anybody come up with a solution since?
Re: Prioritizing Traffic with Unknown Link Capacity
It works as I showed early on in the thread. At least I can say it works here. I'm not sure what isn't working there. There is still no way to specify speed limits (or reservations) as a percentage.It has been a while since I first posed this question.
Has anybody come up with a solution since?
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