Description
A NetworkFunction is a resource which is able to fulfill a well-defined, non-trivial functionality for a service.
Well-defined means that its specialty can be captured by a word understandable across the industry, such as a firewall, a router, a load balancer, etc. Two ways to get to this word:
- the nf_classification property
- the name of a sub-type
It is non-trivial in many senses. First, a NetworkFunction is non-trivial in terms of its connectivity with the outer world. A NetworkFunction-based type is normally defined with multiple capabilities and requirements of different types, which are serving different purposes. Since there is no typical “connectivity set” shared by all function, it cannot be captured by means of TOSCA in the base NetworkFunction node type. That is, the NetworkFunction node type is practically unusable per se. It needs to be further sub-typed, along with extending it with additional capabilities and requirements.
A NetworkFunction is also non-trivial in terms of its internal structure. A NetworkFunction normally has its own internal topology that spans over multiple VMs and has internal networks. A NetworkFunction-typed node is expected to be implemented through substitution. This substitution can be specified by the service designer in design time. However, the service designer may also leave a NetworkFunction-typed node without design-time implementation. In this case, the most appropriate substitution should be found by the Orchestrator in run time.
TODO: explain why this type does not have any capabilities and requirements
Properties
| Name | Required | Type | Constraints | Description |
|---|---|---|---|---|
| nf_classification | yes | onap.datatypes.NetworkFunctionClassification | Structured description of this function. For abstract function nodes, may be used for finding an implementation. |
Attributes
Nothing special
Capabilities
TODO: explain why this type does not have any capabilities and requirements
Requirements
TODO: explain why this type does not have any capabilities and requirements
TOSCA Definition
node_types:
onap.nodes.Resource.NetworkFunction:
description: |
a base of the ONAP hierarchy of network functions
If you have a requirement for a factory, you're allotted
If you have a requirement for a PNFdevice, you're physical
If you have neither, you're virtual.
Expect to see network functions be group members for naming and homing.
derived_from: onap.nodes.Resource
properties:
nf_classification:
description: |
data governed value used by operations to filter network functions
type: onap.datatypes.Classification
required: true
capabilities:
# Expect to define these in the derived node_type, with mappings to appropriate the NetworkFunctionComponent CP
# This exposes external CPs of the NF.
requirements:
# Expect to define these in the derived node_type, with mappings to appropriate inner nodes
Examples
The examples below show possible type definitions of a firewall.
The type AbstractFirewall defines the basic set of properties and connectivity requirements shared by absolutely all firewall networking functions in the world. It captures the fact that a firewall is normally connected to at least 2 networks, and these networks are given descriptive names.
This type can be used as is in a service template to designate an abstraction of a firewall, that can be resolved later by the orchestrator.
The type VerySpecialFirewall below is an example of how could look a concrete firewall node type provided by a vendor. This vendor-specific type extends the connectivity schema of its basic type by the connection to an additional management network.
A NetworkFunction is a resource which is able to fulfill a well-defined, non-trivial functionality for a service.
Well-defined means that its specialty can be captured by a word understandable across the industry, such as a firewall, a router, a load balancer, etc.
It is non-trivial in many senses. First, a NetworkFunction is non-trivial in terms of its connectivity with the outer world. A NetworkFunction-based type is normally defined with multiple capabilities and requirements of different types, which are serving different purposes. Since there is no typical “connectivity set” shared by all function, it cannot be captured by means of TOSCA in the base NetworkFunction node type. That is, the NetworkFunction node type is practically unusable per se. It needs to be further sub-typed, along with extending it with additional capabilities and requirements.
A NetworkFunction is also non-trivial in terms of its internal structure. A NetworkFunction normally has its own internal topology that spans over multiple VMs and has internal networks. A NetworkFunction-typed node is expected to be implemented through substitution. This substitution can be specified by the service designer in design time. However, the service designer may also leave a NetworkFunction-typed node without design-time implementation. In this case, the most appropriate substitution should be found by the Orchestrator in run time.