[Rpm] [Make-wifi-fast] The most wonderful video ever about bufferbloat

[Stuart Cheshire]

On Mon, Oct 17, 2022 at 5:02 PM Stuart Cheshire <cheshire at apple.com> wrote:

> Accuracy be damned. The analogy to common experience resonates more.

I feel it is not an especially profound insight to observe that, “people don’t like waiting in line.” The conclusion, “therefore privileged people should get to go to the front,” describes an airport first class checkin counter, Disney Fastpass, and countless other analogies from everyday life, all of which are the wrong solution for packets in a network.

> I think the person with the cheetos pulling out a gun and shooting everyone in front of him (AQM) would not go down well.

Which is why starting with a bad analogy (people waiting in a grocery store) inevitably leads to bad conclusions.

If we want to struggle to make the grocery store analogy work, perhaps we show people checking some grocery store app on their smartphone before they leave home, and if they see that a long line is beginning to form they wait until later, when the line is shorter. The challenge is not how to deal with a long queue when it’s there, it is how to avoid a long queue in the first place.

> Actually that analogy is fairly close to fair queuing. The multiple checker analogy is one of the most common analogies in queue theory itself.

I disagree. You are describing the “FQ” part of FQ_CoDel. It’s the “CoDel” part of FQ_CoDel that solves bufferbloat. FQ has been around for a long time, and at best it partially masked the effects of bufferbloat. Having more queues does not solve bufferbloat. Managing the queue(s) better solves bufferbloat.

> I like the idea of a guru floating above a grocery cart with a better string of explanations, explaining
> 
>   - "no, grasshopper, the solution to bufferbloat is no line... at all".

That is the kind of thing I had in mind. Or a similar quote from The Matrix. While everyone is debating ways to live with long queues, the guru asks, “What if there were no queues?” That is the “mind blown” realization.

Stuart Cheshire