[Nml-wg] About modelisation of the network description

[Evangelos Chaniotakis]

Aaron Brown wrote:
> 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)
>>   
>>     
> <snip>
> In this view, you might have elements like so to describe the nodes in a 
> certain pop connecting esnet, geant and canarie:
>
> <domain name="Internet2">
>
>     <!-- the definition of the physical elements -->
>     <node name="ciena1">
>        <port name="eth0">
>           <link name="link_to_ciena2" />
>        </port>
>
>        <port name="eth1">
>           <link name="link_to_ciena3" />
>        </port>
>
>        <port name="eth2">
>           <link name="link_to_esnet" />
>        </port>
>     </node>
>
>     <node name="ciena2">
>        <port name="eth0">
>           <link name="link_to_ciena1" />
>        </port>
>
>        <port name="eth1">
>           <link name="link_to_ciena3" />
>        </port>
>
>        <port name="eth2">
>           <link name="link_to_canarie" />
>        </port>
>     </node>
>
>     <node name="ciena3">
>        <port name="eth0">
>           <link name="link_to_ciena1" />
>        </port>
>
>        <port name="eth1">
>           <link name="link_to_ciena2" />
>        </port>
>
>        <port name="eth2">
>           <link name="link_to_geant" />
>        </port>
>     </node>
>
>     <!-- the definition of a pop -->
>     <node name="pop1">
>       <port name="virtual_eth0">
>           <link name="virtual_link_to_canarie" />
>        </port>
>
>       <port name="virtual_eth1">
>           <link name="virtual_link_to_canarie" />
>        </port>
>
>        <port name="virtual_eth2">
>           <link name="virtual_link_to_geant" />
>        </port>
>     </node>
> </domain>
>
> Then, you pass around pop1 to the interested parties as well as give it 
> attributes the same way you might give a node attributes (who is the 
> administrator for this pop, etc), and if they so desire, they can look 
> up the elements that actually make up the pop (those pointers would be 
> included in each of the elements, but they're left out of the example 
> for brevity). The virtual ports could also include as much information 
> as the physical ports that make them up so that they could easily be 
> used for path finding or whatever.
>   
I agree, but I say: formalize that pop1 is the "abstracted" view and the 
rest are
the "detailed" view. If we did that, a network information DB could hand 
out
that single document and applications would select the view that's most
appropriate for their demands and capabilities. 

In the snippet above, there is no way to tell  if pop1 is a real node or 
a "virtual"
node. (and, if you start labeling things, you end up doing something 
quite similar
to views)

And as far as  treating domains and networks as generic Nodes with 
interfaces
poking out: No problem, and I don't see it conflicting with the domain / 
view /
network model. They could (and probably should) all have the NetworkNode
aspect.