Hi Freek, All,
Would it make sense to make a cross-connect a subclass of link?
That is what we had at first. I think we changed because we sometimes want to explicitly say something really is a link, not a cross connect. If a cross connect is a subclass of a link, you can not do so.
We briefly played with the notion of having a abstract class called "relation", of which both link, cross-connect and adaptation are subclasses.
I don't think that we were considering "link" to be a subclass of "relation". I believe that we were considering that what you're referring to as "adaptation" is sometimes a simple relation (a Layer 3 interface atop a Layer 2 interface) and sometimes an active "Service/Function". My perspective is that a cross-connect is a role/type of "link", that a an active adaptation is a "Function/Service" of type adaptation and that a L3 port atop an L2 port is a "relation". best, martin