Re: HFSC not working as expected

[Alan Goodman <notifications@yescomputersolutions.com>]

Thanks Andy,

I have been playing around a bit and may have been slightly quick to 
comment in regard of download...  With hfsc engaged and total limit set 
to 17100kbit the actual throughput I see is closer to 14mbit for some 
reason.

No traffic shaping: 
http://www.thinkbroadband.com/speedtest/results.html?id\x140466829057682641064
hfsc->sfq perturb 10 
http://www.thinkbroadband.com/speedtest/results.html?id\x140466829057682641064

On 06/07/14 17:42, Andy Furniss wrote:
> If you have the choice of pppoa vs pppoe why not use a so you can use
> overhead 10 and be more efficient for upload.
>
> THe 88.2 thing is not atm rate, they do limit slightly below sync,
> but that is a marketing (inexact) approximate ip rate.
>
> If you were really matching their rate after allowing for overheads your
> incoming shaping would do nothing at all.

My understanding is that they limit the BRAS profile to 88.2% of your 
downstream sync to prevent traffic backing up in the exchange links.

>> This works great in almost every test case except 'excessive p2p'. As
>> a test I configured a 9mbit RATE and upper limit m2 10mbit on my bulk
>>  class.  I then started downloading a CentOS torrent with very high
>> maximum connection limit set.  I see 10mbit coming in on my ppp0
>> interface however latency in my priority queue (sc umax 1412b dmax
>> 20ms rate 460kbit) however my priority queue roundtrip is hitting
>> 100+ms. Below is a clip from a ping session which shows what happens
>> when I pause the torrent download.
>
> Shaping from the wrong end of the bottleneck is not ideal, if you really
> care about latency you need to set lower limit for bulk and short queue
> length.
>
> As you have found hitting hard with many connections is the worse case.

Are you saying that in addition to setting the 10mbit upper limit I 
should also set sfq limit to say 25 packets?

Alan