[Bloat] powerboost and sqm

[Jonathan Morton]

> On 30 Jun, 2018, at 9:26 am, Jonas Mårtensson <martensson.jonas at gmail.com> wrote:
> 
> In the flent rrul test, up to about 10 ms induced latency can be seen during the "powerboost" phase but after that it is almost zero. I'm curious about how this is implemented on the ISP side.

Now that is a completely different result.  It looks as though the ISP has *some* kind of smart queue (could just be SFQ) attached to its shaper, but not to the link hardware itself.  During PowerBoost, until the bucket fills up, you see the latter's dumb FIFO instead.

To understand whether the ISP is using SFQ or something that actually performs AQM, you'll need to get a packet dump and look for ECN marks.  The pattern of these might also reveal whether it's a Codel-family or a RED-family AQM (the latter including PIE).

 - Jonathan Morton