[Nsi-wg] SwitchingService presentation for OGF37

[Freek Dijkstra]

A little clarification of my comments yesterday.


NML already contains a Switching Service, which is able to describe the
topological function for both a NSI Switching Service (SS) and NSI
(Connection Service) CS. It is not able to describe NSI functions, like
Policy and how to make the available changes.

Chin mentioned that the difference between the two is that NSI CS is
able to create services, but after a short discussion with Guy we found
that this comment is based on confusion on the term (NSI, unfortunately,
uses the same term for both a "transport service" -a Link in NML- as
well as for the SOAP service that provides the "connection service" -a
SwitchingService in NML-).


Here is a description of the NML SwitchingService:
* It is an object describing the capability to dynamically create Links
between Ports.
* It has an associated list of ingress Ports and egress Ports
* This includes "virtual" or "non-instantiated" Ports that are
dynamically created by a Adaptation Service (aka: it can create
connection between two VLAN Ports, even if that VLAN does not yet exist)
* It keeps a list of created Links
* You can associate a SwitchingService either to a Node (for a NSI
SwitchingService) or to a whole Topology (for a NSI ConnectionService)

And that's all it can. Nothing really fancy, but just what is needed to
described a Switching Service on the data plane.


As an easy way forward, I recommend to make sure that the NSI CS and NSI
SS have a pointer to the NML SwitchingService. Hopefully mandatory, but
if that is easier for quick adoption, optional.

Thanks,
Freek