As described in TMF IG1224, 3GPP identifies services requiring 5G slices as Communication Services (3GPP Term). An example of a communication service would be a service modelled with technology-neutral Customer Facing Service Specifications (CFSSpec). The service model is instantiated as a service instance (end-to-end) of the corresponding Customer Facing Service Specifications and their relationships. The service instance represents the connected flow of traffic in the network, which flow is the actual network service delivering customer traffic from source to destination.
Modelling such a service requires defining the service technically in terms of its service parameters that must meet service quality requirements defined by SLOs. Service parameters are specified in CFSSpecs, and the definition and relationship between CFSSpecs of an end-to-end service evolve from service dependencies within the Service Topology model. The Service Topology model is built from the Network Topology Model, and related Network Traffic flows for the service.
Network Topology model is a resource model that represents a technical domain. (e.g. Carrier Ethernet, DWDM etc). Service Models are models representing services L2 Services (e.g., L2 VPNs, L2 Access) and L3 Services (e.g., L3 VPNs, Service Tunnels) that are ultimately abstracted as technology-neutral before providing to customers. This makes the lifecycle of the service presented to the customer independent of the realization of the services via the lifecycle of the resources and technologies.
In addition, the modelling of such services also needs to consider the management and operations of such services and how tasks that control such services are orchestrated. Such as service creation, modification and termination.
Finally, the modelling of such services also needs to consider the lifecycle of the service itself, how the service specification is created, what its requirements are, how it would be designed and assigned, and how it would be configured and provisioned.
This makes up the CFS-RFS relationship, as I have specified in IG1224 for 5G splicing. To be elaborated on in future posts.