[Nsi-wg] Syntax of NML endpoints in a connection request (was: Determining the Network of an STP)

[Freek Dijkstra]

John MacAuley wrote:

> Just trying to understand how these different proposals come together.

Here is a more realistic NSI sample (namespaces are left out of
simplicity, and I just made up some NSI names, as I'm not familiar with
the NSI syntax):

> <connectionrequest>
>  ....
>  <endpoints>
>     <endpoint>
>        <Topology>urn:ogf:network:nordu.net:2012:org</Topology>
>        <source>urn:ogf:network:nordu.net:2012:onsala-tx?vlan=1791</source>
>        <sink>urn:ogf:network:nordu.net:2012:onsala-rx?vlan=1791</sink>
>     </endpoint>
>     <endpoint>
>        <Topology>urn:ogf:network:sne.science.uva.nl:2012:org</Topology>
>        <source>urn:ogf:network:sne.science.uva.nl:2012:lighthouse-egress?vlan=1791</source>
>        <sink>urn:ogf:network:sne.science.uva.nl:2012:lighthouse-ingress?vlan=1791</sink>
>     </endpoint>
>  </endpoints>
>  ....
> </connectionrequest>

This syntax allows multipoint-to-multipoint connections, if desired. The
nml:Topology tells the recipient in what NSAnetwork the endpoint is
located. NML is unidirectional, and the explicit source and sink makes
sure the direction is unambiguous. These sources and sinks contain URNs
of a PortGroup, with a query part added ("?vlan=1791") that uniquely
identifies a single Port within the PortGroup. It is also possible to
use a URN that just defines a Port directly (without the query part).

I can imagine that a NSI requester does not care about the specific VLAN
that is chosen, and likes to say "just pick any VLAN in this PortGroup".
How exactly that is done, and how to distinguish it from "please connect
ALL VLANs in this PortGroup" is an open question for NSI to answer.

Regards,
Freek