Freek,
I hope this finds you well. I am attempting to model in NML the capabilities of an SDN switch we have in our lab. I am finding the NML specification lacks the detail I need to really understand how some of this would be done. I was not involved in the original discussions so thought I would ask some detailed questions on the examples that are present.
Here some XML from the NML specification defining two port pairs, adaptations, and switching service. I assumed the examples in the NML document were consistent between themselves.
<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF xmlns:nml="http://schemas.ogf.org/nml/2013/05/base#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:nmleth="http://schemas.ogf.org/nml/2013/05/ethernet#">
<nml:Topology rdf:about="urn:ogf:network:example.net:2013:org">
<nml:version>20130529T121112Z</nml:version>
<nml:Node rdf:about="urn:ogf:network:example.net:2013:nodeA">
<nml:name>Node_A</nml:name>
<nml:hasInboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_X:in"/>
<nml:hasInboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_Y:in"/>
<nml:hasOutboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_X:out"/>
<nml:hasOutboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_Y:out"/>
<nml:hasService rdf:resource="urn:ogf:network:example.net:2013:nodeA:switchingService"/>
</nml:Node>
<nml:SwitchingService rdf:about="urn:ogf:network:example.net:2013:nodeA:switchingService">
<nml:hasInboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_X:in"/>
<nml:hasInboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_Y:in"/>
<nml:hasOutboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_X:out"/>
<nml:hasOutboundPort rdf:resource="urn:ogf:network:example.net:2013:nodeA:port_Y:out"/>
</nml:SwitchingService>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_X:out">
<nml:hasService rdf:resource="urn:ogf:network:example.net:2013:port_X:out:adaptationService"/>
</nml:Port>
<nml:AdaptationService rdf:about="urn:ogf:network:example.net:2013:port_X:out:adaptationService">
<nml:adaptationFunction rdf:resource="http://schemas.ogf.org/nml/2013/05/ethernet#802.1q"/>
<nml:providesPort rdf:resource="urn:ogf:network:example.net:2013:port_X.1501:out"/>
</nml:AdaptationService>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_X.1501:out">
<nmleth:vlan>1501</nmleth:vlan>
</nml:Port>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_X:in">
<nml:hasService rdf:resource="urn:ogf:network:example.net:2013:port_X:in:deadaptationService" />
</nml:Port>
<nml:DeadaptationService rdf:resource="urn:ogf:network:example.net:2013:port_X:in:deadaptationService">
<nml:adaptationFunction rdf:resource="http://schemas.ogf.org/nml/2013/05/ethernet#802.1q"/>
<nml:providesPort rdf:resource="urn:ogf:network:example.net:2013:port_X.1501:in"/>
</nml:DeadaptationService>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_X.1501:in">
<nmleth:vlan>1501</nmleth:vlan>
</nml:Port>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_Y:out">
<nml:hasService rdf:resource="urn:ogf:network:example.net:2013:port_Y:out:adaptationService"/>
</nml:Port>
<nml:AdaptationService rdf:about="urn:ogf:network:example.net:2013:port_Y:out:adaptationService">
<nml:adaptationFunction rdf:resource="http://schemas.ogf.org/nml/2013/05/ethernet#802.1q"/>
<nml:providesPort rdf:resource="urn:ogf:network:example.net:2013:port_Y.1700:out"/>
</nml:AdaptationService>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_Y.1700:out">
<nmleth:vlan>1700</nmleth:vlan>
</nml:Port>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_Y:in">
<nml:hasService rdf:resource="urn:ogf:network:example.net:2013:port_Y:in:deadaptationService" />
</nml:Port>
<nml:DeadaptationService rdf:resource="urn:ogf:network:example.net:2013:port_Y:in:deadaptationService">
<nml:adaptationFunction rdf:resource="http://schemas.ogf.org/nml/2013/05/ethernet#802.1q"/>
<nml:providesPort rdf:resource="urn:ogf:network:example.net:2013:port_Y.1700:in"/>
</nml:DeadaptationService>
<nml:Port rdf:about="urn:ogf:network:example.net:2013:port_Y.1700:in">
<nmleth:vlan>1700</nmleth:vlan>
</nml:Port>
</nml:Topology>
</rdf:RDF>
Just so i am 100 percent clear I believe the relationship diagram for the port_X entity looks like this based on the XML provided.
In this example, I assume the deadaptation on port_X:in is stripping the 802.1q header containing vlan tag 1501 from the Ethernet frame, while the adaptation on on port_X:out is adding the 802.1q header with vlan 1501 to the Ethernet frame. Do I have this correct? This seems to be what the NML document is describing. The reason I ask is that I find the naming of the ports a bit confusing and counter intuitive to what I that was occurring.
Where does the physical port associated with urn:ogf:network:example.net:2013:port_X.1501:in(out) come into the picture and how do other vlans on the same port get multiplexed?
Up to this point I have been looking at this from the opposite perspective of what the example in the document describes. From my view the single physical port hasService to a DeadaptationService that providesPort to a set of labeled ports that had been imbedded as client layers within the physical port. If would look like this diagram:
This changes the semantics a bit. It implies that data entering logical port urn:ogf:network:example.net:2013:port_X:out?vlan=1501 will have the 802.1q header added with the vlan 1501 by the adaptation service before multiplexing on physical port urn:ogf:network:example.net:2013:port_X:out. Basically the logical ports continue to fanout upwards in this model and encapsulation/multiplexing is unwrapped.
So have I misinterpreted the NML document and my second diagram here is correct?
Thanks,
John
