[Nsi-wg] Topology virtualisation

[John Vollbrecht]

These are great discussions -

From a topology standpoint it seems reasonable to consider that network-domains consist of resources with common control/ ownership.   This means that a network such as Internet2's ION, or a GOLE such as NetherLight or a Link owned by a third party are all network domains.  This agrees with Freek and Victor - and is what is intended by NSI descriptions.

For pathfinding and policy allowing a link to be a separate domain connected to other domains allows the link to have its own policy, enforce by itself.  Note that the domain could delegate topology enforcement to one or the other of the domains to which it connects, but it is still its policy that gets enforced.

From a control standpoint a GOLE is like any other domain.  It makes and breaks connections, and is controlled by its owner.   

A domain of a single link however seems different - there is no way to control that link, it is on or available all the time.  There seems no good way to allow the link to have control of its use if adjacent domains connect to it.  I think that if control is required that adjacent domains must have an SLA with the link that requires them to honor the link policy.  

-- John



 
On Jun 28, 2010, at 8:56 AM, Freek Dijkstra wrote:

> Gigi Karmous-Edwards asked:
> 
>> So, how is this modeled? Victor suggests having the link between two 
>> GOLEs as a single domain?
> 
> This is a good approach IMHO. It allows one to add a policy to a link.
> And as Erik-Jan eloquently pointed out, a link can have a policy.
> 
>> I think the key question that started this debate was: Are GOLEs 
>> significantly different from Domains such that we need to model them 
>> differently?
> 
> Bearing the KISS principle in mind: If they can be modeled the same way
> for path finding, then I would do so. That would make the architecture
> more simple, and thus more powerful.
> 
> I have not yet seen a compelling reason to model them differently. Such
> reason might still be there (I can imagine that it would speed up things
> knowing beforehand that a GOLE has no internal bottlenecks or is policy
> free.), however, I have not seem a simulation to prove that.
> 
> Regards,
> Freek
> 
> 
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