Re: [babel] New Version Notification for draft-ietf-babel-rtt-extension-06.txt

[David Schinazi <[e-mail]>]

Thanks Juliusz, this helps.

First, to set the stage - I'll be happy with any option you select, this is
just to assuage my curiosity.

In terms of the differences between the various options:

1) ease/possibility of implementation
This one is important, but - if we assume that all implementations don't
need to match - then we can just say "SHOULD implement as low in the stack
as you can" and everyone can do that on whatever platform they are

2) symmetry
As you point out, since RTT is the sum of both one-way delays, it will
always be symmetric :-)

3) scheduling jitter
I would assume that it's best to not count scheduling jitter since that'll
most likely pollute the measurements and not impact the actual flow of
packets along this route

I guess the bit I'm not sure about is the assumption that I mentioned
above: the fact that implementations don't need to match. Is there any
reason why we'd want them to match?

David


On Thu, Apr 18, 2024 at 7:41 AM Juliusz Chroboczek <[e-mail]> wrote:

> > Properties of δ:
>
> >   - it's not symmetric (it only includes local queueing delay);
>
> > Properties of η:
>
> >   - it's not symmetric;
>
> Sorry, that's not correct.  All three measures are symmetric.  Mills'
> algorithm is just too brilliant for my small brain to encompass.
>
> -- Juliusz
>