[Nml-wg] NSI topology proposal

[Freek Dijkstra]

Jeroen wrote in the notes:

> We had a short discussion on whether NSI descriptions and physical
> topology descriptions are different things. One is something like a
> service, the other is the actual instantiation of it. This is similar
> to identifiers for books, stories, translations and physical books.
> Freek remembers that libraries have a solution for identifiers on
> those things, he will try to get a link to that and post it.

My feeble attempt to translate library versioning concepts to IT:

* work - Eg. "Gone with the Wind" or "Browne natural language corpus"
* expression - Swedish translation of the work - software implementation
* manifestation - hard cover of the expression - Excel sheet or XML file
* item - actual book on a shelf - copy on a disk

Anyway, in NML we currently have a "Lifetime" for each network element
(it's in the diagram). I wonder if the aliases Jerry mentioned in his
slides are a better way to handle versioning.
(Assuming this is all different from topology aggregation.)

Freek