Re: [Din] draft-mazieres-dinrg-scp-04 peer priority algorithm

[Piers Powlesland <[e-mail]>]

Hi David,

The new wording looks good to me.

And thanks for clarifying the 2 stage approach to choosing a preferred
peer, I can see now that my approach would not correctly reflect the
importance nodes as they appear in SCPSlices.
On Tue, Aug 7, 2018 at 9:08 PM David Mazieres
<[e-mail]> wrote:
>
> David Mazieres <[e-mail]> writes:
>
> >> As I understand, this filtering could lead to a situation where the
> >> neighbours set is empty, since there is no guarantee that any hash
> >> calculated above will be less than '2^256 * weight(peer_id)'. Is this
> >> intentional?
> >
> > There is a guarantee, because a node must belong to all of its own
> > quorum sets.  So even if a node has no other neighbors, it will still be
> > its own neighbor... which highlights the fact that maybe "neighbor" is a
> > misleading term here?  Or maybe at least suggests we should mention
> > this.
>
> I went to clarify this in the draft and realize it's not clear at all
> because of the way slices are defined.  (You implicitly have to be in a
> quorum, but it never says you are in every slice.)  So I propose the
> following wording on neighbors:
>
>    o  Define the set of nodes "neighbors(n)" as the set of nodes v for
>       which "Gi(1 || n || v) < 2^{256} * weight(v)", where "1" and "n"
>       are both 32-bit XDR "int" values.  Note that a node is always its
>       own neighbor because conceptually a node belongs to all of its own
>       quorum slices.
>
> David