[jdev] Semantic question

[Goffi]

Thanks for you answer Dave (and Adrien),

So we can talk about federation for different protocol (if I add a 
gateway to my server, I add a federation with the legacy network), right ?



On 30/04/2015 12:54, Dave Cridland wrote:
>
>
> On 30 April 2015 at 11:23, Goffi <goffi at goffi.org
> <mailto:goffi at goffi.org>> wrote:
>
>     G'day,
>
>     for years I have used decentralised, distributed, and federated
>     with, in my head, the following meaning:
>
>              - decentralised: the ability to have several servers
>     communicating together, the servers can be under the same domain
>     (example.net <http://example.net> can have several servers)
>
>
> By "decentralised", I really just mean it has no centre - there aren't
> any special, or especially privileged, servers.
>
> XMPP fits this description, but not all services built on XMPP do - for
> example, if we had a single user directory (and I think one such did
> exist at one point) that would be a centralised service.
>
> Matrix has identity servers, which are a centralised trusted naming
> service, DNS is similarly centralised (due to the root service).
>
> In neither case are the "centralised" servers a single entity; they're
> just a privileged set, providing a distributed service.
>
> Of course, these all assume actual servers, and a service defined in
> terms of a simple protocol. For a particularly odd example, consider
> PKIX, where we have multiple, fully independent, Certification
> Authorities forming a heterogeneous privileged set of providers - PKIX
> is clearly not decentralised, but has multiple central points...
>
>              - distributed: 1 server = 1 user, no intermediate (not even
>     DNS, so XMPP is not distributed according to this definition, but
>     something like retroshare is)
>
>
> Your definition fits what people tend to mean by "peer to peer",
> although s/user/device/.
>
> Almost anything can be described as distributed.
>
> It might mean a service which is available equivalently at multiple
> points on the network. Which really doesn't say anything useful.
>
> It might mean a service which is provided equivalently by multiple
> points on the network; that's a slightly tighter definition, but covers
> clustered XMPP servers, for example.
>
> I suspect people usually intend to mean a service which is provided
> equivalently by a decentralized set of providers, and in extremis they
> can mean peer to peer.
>
> Well, no.
>
> People usually seem to mean "whatever it is that we do", and use it
> liberally on marketing brochures.
>
>              - federated: the ability from servers of different domains
>     (example.net <http://example.net> and capulet.lit) to talk together,
>     in both directions.
>
>
> Yes, or more generally, the ability for multiple disparate
> administrative domains to intercommunicate on an equal basis.
>
>     But after a talk I realise that the definitions accepted is not the
>     same everywhere, e.g. Diaspora people talk about federation for what
>     I call decentralisation. Actualy it's a bit tricky, because if one
>     entity has 1000 servers but everybody is using the same domain, the
>     data are centralised in the hands of the same entity.
>
>     So, what meaning do you put behind these words ? Are
>     decentralisation and federation more or less synonyms ?
>
>     Sorry to put this on jdev@, I was not sure of which mailing list to
>     use :)
>
>
>     Goffi
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