Hi Jeroen Ok, I finally got your point.
My point is that the splitting of VLANs happens outside of your domain and outside of your control. So yes, it is going to happen somewhere in a switchingmatrix, but you cannot control it.
So, how do you want to describe this? Do you want to introduce a Node/SwitchingMatrix that is there but you do not control?
But isn't this the issue of topology exchange? And building a global topology from multiple sources. The SwitchinMatrix that does the splitting would be contained in the topology for domain B. The domainA would just describe its edge port, and the link to the other side. (With most likely the adaptations into Ethernet) So indeed you cannot introduce a Node that you do not control, because a priori you do not know of its existence. In a first moment, without having built a global view of the network you do not know what has happened to the vlan 1000-2000 and 3000-4000 that you just "threw over the fence". When a gloal topology gets constructed from the various sources consistency gets checked. The utlimate point I was trying to make was that in my opinion the schema you mailed us allows us to describe this usecase. Best regards, Paola