[Nml-wg] About modelisation of the network description

[Evangelos Chaniotakis]

Freek Dijkstra wrote:
> Evangelos Chaniotakis wrote:
>
>> I'm on the fence as to whether we need a separate "network" concept.
>> We might need to model administrative domains that run multiple
>> independent networks.
>
> You totally convinced me. So:
>
> DOMAIN = administrative domain = an organisational entity that is 
> responsible for the operational control of resources (including 
> network resources)
>
> NETWORK = a collection of network elements that behaves as a single 
> resource (it is possible to describe the functionality without 
> exposing the internal implementation or detailed internal limitations)
>
> I don't know how to describe VIEW. Evangelos, Aurélien, do you have 
> suggestions?
>
I would say that a Network is a collection of Views, and a View is a 
collection of
Network Elements. I don't think either "behaves like a single resource" but
maybe we're thinking of different things.


<snip>
> Shouldn't that be:
>
> - Domain
> --- Network
> ----- View (type = "monitoring")
> -------- Network Element
> -------- Network Element
> ---------- Network Element
> -------- ....
> ----- View (type = "controlplane")
> -------- Network Element
> -------- Network Element
> -------- ....
> ----- View (type = "export")
> -------- Network Element
> ---------- Network Element
> -------- Network Element
> -------- ....
> --- Network
> ------ ....

Well,  I was still on the fence about the Network element, that's why I 
didn't
include it there. But I agree with the above; I think we should have Views
under Network.


> A few questions about your tree.
> * May a single network element occur in multiple views (I assume so)
Yes.
> * Must a network element be part of only one domain (I assume so)
I would say yes. Although there's certainly some real-world scenarios
where multiple administrative domains share some infrastructure, I don't
think we should model this.


> * Can a view consist of network elements in multiple domains? (I 
> really don't know about this one, but if true, a view can also be 
> higher in the tree than a network)
>
I would say no. It's certainly conceivable, but let's keep Views under 
Network.



> Given your tree, am I correct to assume these relations:
> domain:network = 1:many
>   (each network is under control of only one domain)
> network:view = 1:many
>   (a view can only contain network elements within a single domain)
> network element:view = many:many
>   (a network element can occur in multiple views)
> network element:network = many:1
>   (a network element can only be part of one network)
This looks right to me.