Hi Freek, everyone. The short answer is, in the PerfSONAR/IDC schema we're using Port to refer to a physical interface, and Link to refer to the logical interfaces running on a Port. The names are slightly misleading, I guess. This representation has the advantage of simplifying things, mostly because broadcast segments and such are not represented as separate objects; all connections between interfaces are represented by the point-to-point Link -> remoteLink construct. Of course this is not the "real" picture of the network, but in practice this representation does seem to fit the current needs of the PerfSONAR / IDC community. Freek Dijkstra wrote:
Aaron, Martin,
Thanks for creating the UML schema! It's very useful to start a discussion.
I have two questions.
First, what is the differences between Network and Domain? [1] It was discussed today, but couldn't really understand the details by phone.
Second, the relation Link-Port in PerfSONAR is different from the relation Link-Interface in NDL [2]: in PerfSONAR it is many to one, while in NDL it is one to many. So, I understand that a Port in PerfSONAR can be connected to multiple links, but a link can only have one Port. I don't really understand. Can you give me an example?
In NDL, a Link can have multiple Interfaces (typically 2). An interface is a logical interface, that is only connected to one link. If there would be multiple links, we would describe that with multiple (logical) interfaces (or with a BroadcastSegment).
Regards, Freek
[1] The difference between NetworkDomain and AdminDomain in NDL is that a NetworkDomain is a collection of network resources, while an AdminDomain is a collection of people (= an organization!): the people or organization that is responsible for managing the resources. The resources of an AdminDomain are not limited to network resources, but could also include CPU, storage, vizualization, services, etc.
[2] A Link in NDL is a special case of a BroadcastSegment: a broadcast segment with exactly two interfaces.