On Jul 12, 2012, at 4:58 AM, Freek Dijkstra wrote:

Last, a long-time discussion:

Roman spotted another issue:

The idRef="urn:ogf:network:nordu.net:2011:NORDUnet:org" does not
appear to point at anything.

Freek replied:

Good catch. Frankly, the difference between id and idRef is never
properly defined.

Roman clarified:

The idea of id and idRef was taken from NM/NMC and it's very useful
to make distinction between definitions and references to those
definitions.

I am aware of the origin, but will repeat my original rather firm
statement: I've never seen a proper definition of the difference between
the two. I've seen vague statements about origin, but I do not think
that NML should use id/idRef to make statements about origin, if only
for the reason that RDF does not contain id nor idRef.

We did try to come up with a proper solution in
https://forge.ogf.org/sf/go/artf6555

But that discussion was stranded by some terminology discussion in the
related https://forge.ogf.org/sf/go/artf6553 (warning: long read)

We did not get a consensus on the terminology, let alone find a solution
how to encode it in either XML or RDF.

I encourage you to come up with a good explanation what you want to
distinguish between, and how you want to make that distinction -- both
in XML and in RDF.

I am looking forward to that proposal, but by lack thereof, I claim that
we're better of without the id/idRef distinction, since it will only
lead to confusion.

I don't have a strong opinion on using id/idRef, as the method, but the idea is based around inheritance. As an example, you have port P defined in topology T. When referencing the port in topology S, I might want to override some of its properties (e.g. include our name for its Port). Another example might be the example I sent to the NSI list where I override the VLANs of the PortGroup so that the VLAN is chosen from a subset of the VLANs available.