[Nml-wg] NML : Adaptation questions.
John MacAuley
macauley at es.net
Fri Dec 2 11:11:08 EST 2016
Freek,
I need another clarification on terminology in the Adaptation/Deadaptation elements:
> canProvidePort to one or more Ports or PortGroups (this describes a ability)
When you say "this describes an ability" do you mean that the Port or PortGroups listed are available for use but are not yet in use?
> providesPort to one or more Ports or PortGroups (this describes a configuration)
I would then assume this represents the Ports or PortGroups currently in use by the function?
If both of the above assumptions are true, then must a specific port being used in providesPort be removed from the canProvidePort list?
Thank you,
John
Begin forwarded message:
> From: John MacAuley <macauley at es.net>
> Subject: NML : Adaptation questions.
> Date: 1 December, 2016 6:40:03 PM EST
> To: Freek Dijkstra <Freek.Dijkstra at surfsara.nl>
> Cc: Network Markup Language Working Group <nml-wg at ogf.org>
>
> 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
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