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The ETSI information model is all defined in terms of information elements and their attributes. TOSCA proposes a much richer and more flexible meta-model; besides nodes and their properties, it offers to a designer such constructs as capabilities, requirements, relationships, policies, artifacts, interfaces, relationships, etc.
ETSI & ONAP Information Elements | TOSCA Constructs |
|---|---|
Descriptors: NSD, VNFD, PNFD | Topology Template to describe the internal composition and other implementation details; Node Type to express the “interface”; Node Template to represent an occurrence of the service/function within a higher-level composition (see Modelling Complex Resources) |
VLD, CpD | Normative Node Types and Node Templates based on these types (see |
Information Elements | Data Types |
Naming, Scaling, Affinity | Policies |
Lifecycle, Operations | Interfaces |
Operation scripts, software images, etc. | Artifacts |
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Properties vs. Metadata Fields
Property | Metadata Field |
|---|---|
Has to do with the core business purpose of the model object, what the model does. | Tells how the model object is maintained, stored, displayed, handled by business logic, etc. |
Examples: IP address, required amount of memory, virtualization container type | Examples: Author name, release number, change timestamp, ID in the data store |
Populated by vendor, designer | Populated by the infrastructure logic |
Inherited by derived types | - |
Used by functions (i.e. get_property()) | - |
Has a data type, including constraints to observe | No structure, just a loose string |
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Design-time resource instances
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A resource occurrence maybe?
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Modelling Simple Resources
A simple resource is a resource that cannot be decomposed into a topology of lower-layer component resources. Possible ways for a resource to be simple:
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- A TOSCA node type is used to model the simple resource definition.
- TOSCA node templates of this node type are used to represent occurrences (design-time instances) of this resource within a higher-level composition topology.
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Modelling Complex Resources
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