[mdx] MDX & expressing communites-of-interest

[Josh Howlett]

(Another policy-related post, that attempts to adhere to Chad's T&Cs by
addressing a technical requirement)

Our federations are typically implemented as communities-of-interest
that are comprised of parties making promises about the way that they
will behave to each other and the federation operator.

There is a view (and I hope I am summarising it accurately) that since
these promises are only made to federation operators, member
organisations should take their own steps to protect themselves if
entering into any significant relationship (because an aggrieved party
can't enforce a contract between two other counterparties). Therefore,
federation metadata (and by extension, MDX) should be considered a
promise-free zone; the only property of interest is the 'LoA' associated
with the metadata registration, as this allows you to establish the
counterparty-to-entity binding.

Nonetheless, situations do exist where people do behave in ways that
strongly indicate that these types of agreements do instil a level of
trust between actors in communities, even if they don't formally have
any legal recourse. A good case of this is eduroam, but there are
others.

Consequently, I feel that it might be useful for MDX to be able to
express an association or membership within a particular community(s),
irrespective of its legal enforcability. It can be treated as evidence
that a metadata consumer can take or leave.

It is not clear to me how this association/membership of a
community-of-interest should be expressed; I see the following options:

 - tag the EntityDescriptor
 - publish the EntitiesDescriptor for a community-of-interest at a Well
Known Location, that members of that community can fetch it from.

Any opinions on this?

josh.

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