Role of Instance Model

[Luca Gioppo <luca.gioppo@csi.it>]

On chapter 17 I'm reading little about the Instance Model.

It was confusing to me already in the XML standard, but chapter 17 little helps in understanding how it differs from the topology and how it is used.

Can anyone shed some light on this?

Is it a topology with the implementation data written in place of the get_attribute or so on?

Is there some standard way to write it or is a free for all?

Thanks

Luca