[Nml-wg] NMLify of AutoGOLE topology

[Roman Łapacz]

W dniu 2012-02-22 22:50, Freek Dijkstra pisze:
> Jerry Sobieski wrote:
>
>> Exactly.  I view a topology as [initially] an abstract domain that
>> comprises a comprehensive but finite switching function between points
>> at its boundary.   We can map those points to co-registered points in
>> another topology that expresses some other aspects - perhaps
>> geolocation, or internal connectivity, or policy-based capabilities, or
>> a combination thereof.  A perfect example would be a simple abstract
>> topology announced publicly that mapsTo a much more detailed internal
>> physical topology that the local network wishes to manage itself.   The
>> NSA is the agent that speaks to other NSAs inter-domain (at whatever
>> domain level we are at) and translates as necessary to local agents that
>> do the dirty work internally.
>> It is important IMO that NML be recursive and abstract in this manner as
>> well as able to capture physical hdw engineering trappings.    It looks
>> like it is very close to being able to do this.
> NML is partly capable of defining recursive topologies.
> * It does not dictate till what level a topology should be abstracted,
> and is designed to make this irrelevant (I recommend to give figure 7 of
> ITU-T G.800 a good stare: "Example of recursive partitioning")
>
> * NML does not yet define how to tie topologies of different abstraction
> together, other than that all ports at the edge of a the more abstract
> topology will also be ports at the edge of the less abstract topology,
> and should (in my view) get the same identifier.
> A 'mapTo' relation may be a possibility.
>
> We played with the concept of virtualisation during OGF 23 in Barcelona
> (see https://forge.ogf.org/sf/go/doc15482), which does this for nodes
> (both partitioning a physical node into smaller logical nodes as well as
> grouping nodes into something that we now call a "topology"). The
> discussion was resolved by making all concepts: both node and topology
> abstract. Thinking about it, if nodes in NML are also abstract, perhaps
> both concepts (topology and node) are the same, only on different levels
> of abstraction.
>
> I like to hear from nml-wg participants:
> - if they think that NML should be capable of defining a topology at
> different layers of abstraction

Yes but I would make this more general and say - just different layers. 
They could be abstractions or tech layers (I'm thinking that layers may 
be also a good solution to control publishing information by configuring 
somehow that only some layers can be distributed, others not; a single 
abstraction could be split into more layers because of some reasons; it 
would be up to the implementation)

> - how these different descriptions should be tied together. Should we
> define a relation between them?

I think so. The work on examples will help to progress.

Roman

> For the NSI participants I'm interested in hearing if you think that
> only NML should define different levels of abstraction, or if you also
> expect NSNetwork to have different levels of abstraction, and if an NSA
> have different levels of abstraction. (I presume both have, given that
> NSA supports a tree-like request structure, where a top-NSA can delegate
> requests for path provisioning to other NSA).
>
> Regards,
> Freek
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