Hi Jan,
> > -- "However, there is no mean for the peers to verify whether the
> > information provided is actually intended
> > for their usage nor if the information is actually accurate at their
> > current topological position in the Internet "
> >
> > Surely, it's very important to verify the usage and the origination of
> > the
> > redistributed information.
> > I don't think accurate information needs to be redistributed.
> > Actually, there are kinds of general information that are suitable and
> > helpful to be redistributed.
> > E.g. kinds of cost between a particular PID and other PIDs is useful to
> > all
> > the peers in the particular PID.
> > What we should do is to guarantee that general information is
> > redistributed
> > within the PID area(maybe multicast) or to guarantee that peer only
> > request
> > its PID general information.
>
> Agreed, there may be certain use-cases where redistribution may not be
> problematic. But consider the case where certain information provided by an
> ALTO-server is _relative_ to that ALTO-server's location in the network. If
> such information gets redistributed, an ALTO-client not being aware of the
> original ALTO-server's location may misinterpret this information. In other
> words, by redistributing guidance information, its original semantic might
> be disguised. I think this is the problem being addressed in Martin's draft
> and specifically in the quote above.
The redistributed ALTO information should indicate the ALTO Server from which
it originated, and the parameters that were supplied to request that
information. For example, when looking at a listing of the available ALTO
information, an peer can look for the ALTO server it would have contacted
otherwise (perhaps, hostname:port of the ALTO server), and grab the ALTO
information pertaining to that server.
This "listing of available ALTO information" could be posted on a public
website (available as direct downloads, torrent files, etc). Another option
would be to distribute via a DHT (a la Vuze's Distributed Tracker) where the
key is hash("alto:<hostname>:<port>:networkmap"). Something similar could be
used to request the full cost map:
hash("alto:<hostname>:<port>:costmap:<costtype>")
To redistribute only a portion of the cost map (e.g., a row of the matrix from
the perspective of a single PID), then the map could be stored at
hash("alto:<hostname>:<port>:costmap:<costtype>:<pidname>").
--
Richard Alimi
Department of Computer Science
Yale University
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