[Bloat] First draft of complete "Bufferbloat And You" enclosed.

Dave Täht d at taht.net
Thu Feb 10 12:50:04 EST 2011


Jim Gettys <jg at freedesktop.org> writes:

> Well, another way to think about transport protocols is as servo
> systems, that apply feedback to control the rates.
>
> If you look at the TCP traces that set me off on this merry chase, you
> see quite violent periodic behaviour, where the periods are quite long
> (of order 10 seconds).
>
> Injecting delays way beyond the natural RTT is hazardous to the
> stability of transport protocols.
>
> You can see TCP slowly losing its mind it's RTT estimation gets longer
> and longer as the buffer fills.  Eventually, it goes ballistic.
>
> The servo system's stability has been destroyed...

I LIKE the idea of trying to think about this as a complex servo system.
I also like many of the other analogies that have gone by.

At the moment, the lower levels of plumbing in the internet's servos
more closely resemble a rube goldberg machine.

Everybody here could use a belly laugh. Try this:

http://www.youtube.com/watch?v=qybUFnY7Y8w

We've also been overcomplicating this discussion, getting overwhelmed in
detail.

There is no perfect analogy, all we can do is - as blind men feeling up
this elephant from trunk, hip and tail - is to keep trying to describe
its shape in as many different ways as possible until it's more than a
shadow on the wall... [1]

If we can take a step back and not go for one-size-fits all and think of
each audience that we need to address, perhaps we'll keep finding
analogies that work for each audience in smaller, more digestible, pieces.


> 			- Jim
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> Bloat at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat

[1] Plato and the Elephant - coming soon to a writers workshop near you!
-- 
Dave Taht
http://nex-6.taht.net



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