[Cake] [Bloat] active sensing queue management

David Lang david at lang.hm
Sat Jun 13 00:34:45 EDT 2015

On Fri, 12 Jun 2015, Daniel Havey wrote:

>> ii) Sebastian points out if you implement AQSM in the modem (as the paper
>> claims :p), you may as well BQL the modem drivers and run AQM.  *But that
>> doesn't work on ingress* - ingress requires tbf/htb with a set rate - but
>> the achievable rate is lower in peak hours. So run AQSM on ingress only!
>> Point being that download bloat could be improved without changing the other
>> end (CMTS).
> This is pretty cool.  I had not considered BQL (though Dave and Jim
> were evangelizing about it at the time :).  This solves the
> upload/download problem which I was not able to get past in the paper.
> BQL on the egress and ASQM for the ingress.  BQL will make sure that
> the upload is under control so that ASQM can get a good measurement on
> the download side.  Woot!  Woot!  Uncooperative ISP problem solved!
> BTW...Why doesn't BQL work on the ingress?

for the same reason that AQM doesn't work on inbound connections. you're on the 
wrong side of the link :-)

implementing AQM and BQL on the ISPs device that's sending to the home user is 
a perfectly reasonable thing to do and is really the right answer for the 

all the rest of this is a matter of "we can't get at where the problem really is 
to fix it, so let's figure out what else we can do to mitigate the problem"

David Lang

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