Subject: [aqm] AQM support in the network

From: Mirja Kühlewind <[email-masked]>
Date: Tue, 19 Mar 2013 09:06:32 +0100

Hi,

I was thinking about a way how to measurement if AQM is used in a network... 
(if someone has ideas please tell me)... but then I though instead of 
spamming the networks with measurement traffic, I might just asked network 
operators directly :-)

Not sure who is subscribed to this list, but as a starting point I would like 
to ask anybody who reads this and is in charge of operating any kind of 
network (isp, cdn provider, or smaller local networks) to post to the list, 
if AQM is used anywhere in the network!

Of course it would also be helpful to tell where AQM is used and which kind of 
AQM also which parameters. I know that people might not be allowed to say, but 
maybe you could at least indicate if it is used somewhere or not. Please also 
tell if you don't use AQM anywhere. Maybe you might also be able to explain 
the reasons why AQM is not used...?

Thanks in advance!
Mirja

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From: Mikael Abrahamsson <[email-masked]>
Date: Tue, 19 Mar 2013 10:40:59 +0100 (CET)

On Tue, 19 Mar 2013, Mirja Kühlewind wrote:

> Not sure who is subscribed to this list, but as a starting point I would 
> like to ask anybody who reads this and is in charge of operating any 
> kind of network (isp, cdn provider, or smaller local networks) to post 
> to the list, if AQM is used anywhere in the network!

I would imagine that most ISPs use AQM on their core links, but this AQM 
is more WRED kind of AQM, where you have a few queues and place the 
traffic into each queue based on DSCP/EXP values. This is mostly used to 
assure certain amount of bandwidth/loss profile to certain services, such 
as the providers own VoIP or IPTV service.

> Of course it would also be helpful to tell where AQM is used and which 
> kind of AQM also which parameters. I know that people might not be 
> allowed to say, but maybe you could at least indicate if it is used 
> somewhere or not. Please also tell if you don't use AQM anywhere. Maybe 
> you might also be able to explain the reasons why AQM is not used...?

Are you defining AQM as anything that is not FIFO?

-- 
Mikael Abrahamsson    email: [email-masked]

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From: Jim Gettys <[email-masked]>
Date: Tue, 19 Mar 2013 14:32:32 -0400

On Tue, Mar 19, 2013 at 5:40 AM, Mikael Abrahamsson <[email-masked]>wrote:

>> like to ask anybody who reads this and is in charge of operating any kind
>> of network (isp, cdn provider, or smaller local networks) to post to the
>> list, if AQM is used anywhere in the network!
>>
>
> is more WRED kind of AQM, where you have a few queues and place the traffic
> into each queue based on DSCP/EXP values. This is mostly used to assure
> certain amount of bandwidth/loss profile to certain services, such as the
> providers own VoIP or IPTV service.

You might imagine so.  But from what I've seen, you'll often be
disappointed.   Your mileage will definitely vary.

Jim

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From: Mikael Abrahamsson <[email-masked]>
Date: Tue, 19 Mar 2013 19:37:02 +0100 (CET)

> disappointed.  Your mileage will definitely vary.

It's been a long time since I last saw buffering of more than 50ms on a 
congested core link (I'm talking 1G link or up).

But we're talking about 90% of the traffic being DSCP BE going into a 
single queue with RED dropping most traffic around 50ms of buffer depth.

That's why I was saying that I don't really want to call this AQM. It's 
not very "advanced".