Re: connectedness & coordination

> Consider, for example, a researcher who desires to use a collection
> of co-located servers and storage devices attached to a common
> switch.  How and by whom is the switch configured?  If the current
> state of the switch, say because of support for other experiments,
> prevents interconnection between some components, how is that
> represented and resolved?
>
> I have pieces of two possible answers: First, the switch may be
> considered a component and its configuration is the responsibility of
> the experimenter.  If so, there needs to be a way to express the
> desired connectivity and constraints within RSpecs or some other
> way.  (I recall discussion of the need for a connectivity graph of
> some sort.  Is that right?  Where does such a thing live?  How is it
> accessed?)
>
> Alternatively, an aggregate controller could be used to configure the
> switch and select connectable components.   This makes the resource
> allocation problem the controller's, which makes sense since the
> controller would presumably also be handling the resource  
> reservations.
>
> But what about the case when there are connectivity constraints that
> cross aggregates? (Or, there are no aggregates?)  For example,
> consider an experiment requiring components are distributed across
> the GENI system.  There may be multiple, diverse networking resources
> available connecting subsets of the facility.  How does a researcher
> discover whether or not "he can get there from here."