nml-wg discussion

NML-WG: Monday brainstorming Feb.25 ‘08 - OGF22

NML-WG discussion


UML diagrams comparison

Basic classes are further extended by using Layer information:

• PerfSONAR basic classes: – Domain Node Port Link Path Network Service Location

• NDL basic classes:– Administrative_domain Network_domain Device Interface

Link Location Service

• cNIS basic classes:– (generic) Node Link Interface Location. (Concept of basic

class grouping to allow description of domains, networks, etc)


Common classes

Common classes:

• Group (specialized with well known names: group type= administrative domain, network domain, path etc.)

• Node/Device • Interface/Port• Link• Location• Service


Group

Group = abstract type that becomes specialized depending on elements we put it. Ordered and unordered group:

General Path (a specialized ordered group): ***Link path:Domain path:Loose path:

Domain (a specialized unordered group):Network domainAdministrative domainVLAN domain

*** do we want to keep Path in here (as it is the only type of ordered group we can think about) or should be moved out of Group (only unordered)


Node/device

Node: ***

*** Extension of this class with layer-specific information might follow (layer1, layer2, layer3 node ….)


Interface/portInterface/port: ***

Every interface belongs to a node (for interdomain links the far end node may be unknown)

Layer1 interfaceFiber interfaceOTN interface….

Layer2 interfaceSONET interfaceEthernet interface…..

Layer3 interfaceIPv4 interface…..

*** Are technology-specific interfaces (I.e Ethernet interface) subclasses of the layer interfaces (I.e. Layer2 interface) or subclasses of the generic interface?


Link

Link: - composed of two interfaces (start and end);- links are unidirectional;- links can/are hierarchically organized (a layer3 link =

sum of to layer 2 links) ***- concept of link aggregation (serial links and parallel

links)- Can be recursive

*** how do Links and Paths (Link paths) relate to each other? Is the first a physical object and the second a logical object?


Location

Location:- Describe a physical point in space (by using geo-coords,

street names ….)- A Node is one Location at the time, Links can pass through

multiple Locations (I.e. they go through an ordered group of geo-coords)


Service

Service:Application serviceNetwork service…..

Are services offered at a Domain level (with Domain being a Group of Nodes) or by a Node or an Interface directly? What is the distinction between a Service and a capability?


Common relationships

How the classes related to each other: concept of one-to-one, one-to-many and many-to-one, any-to-any.

Comprises, composed of, …are relationship blocks.One to one:One-to-many:Many-to many:Any-to-any:

‘self recursive’ and ‘composed of’. Are these are two distinguished ideas? self recursive is not a group; composed of represents a

many to many relationship and is described by a group.


Next steps• Definition of basic NML-WG schema classes and attributes

• Validation against existing usecases

• Which tools we will use to actually produce/write/develop the schema?– UML diagrams– RDF and XML as exchange formats: translations tools between the

two. Best practice representation in RDF and XML of the basic ontologies. Adopters are free to choose other syntaxes as they wish.

nml-wg discussion

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