[Nml-wg] Multiple namespaces

[Freek Dijkstra]

Last week's mail conversation drifted from XML syntax for NML relations
to the use of namespaces in NML messages.

An important difference in view was identified.
Jason assumed that a single NML messages would only contain one namespace.
I assumed that a single NML messages would only contain multiple namespaces.

While a few example crossed the list, those were very probably not very
relevant nor convincing. So I'll explain a bit better how I envision the
different namespaces:
- core topology concepts (link, node, port, adaptation, ...)
- Ethernet-specific topology concepts (VLANs, segment size, ...)
- IP-specific topology concepts (IPv4/IPv6 address, routing table, ...)
- geography enhancement (geo location)

and I potentially see a mix & match with other applications:
- path finding, topology aggregation, domain control (NSI, provisioning)
- monitoring, performance (NMC)

I expected and still expect each of the above to go in a different
namespace.

The above leads to three scenario's in mind where it may be prudent to
mix namespaces in a single message:
- core topology with technology specific (Ethernet, IP, ..) namespaces.
This is probably the weakest use case, as it is possible to add the core
topology concepts to each technology specific namespace (e.g. using
chameleon namespaces)
- topology namespace with geo namespace
- topology namespace with an application-specific namespaces (eg.
topology + NSI for path finding, or topology + NMC for monitoring).

Regards,
Freek