Page 689 - Cloud computing: From paradigm to operation

XaaS 3

Figure 8-3 – OSS-NaaS functional components

The OSS-NaaS functional components include the following OSS functional components:
1) Service catalogue functional component (see clause 9.2.5.3 of [ITU-T Y.3502]). This component
includes a listing of all cloud services of NaaS CSPs including the relevant NaaS services;

Modelling is needed for ensuring an efficient control and management of the NaaS services, policies,
and resources by the NaaS CSP. The following models used for NaaS service instantiation
(see clause 7.2.2) are needed in the service catalogue:

– NaaS service models
A NaaS service model provides the information model of a given NaaS service (e.g., VPN as a
service (VPNaaS)) being offered by the NaaS CSP. NaaS service models are used for creating and
deploying NaaS service solutions by the NaaS CSP. In a NaaS service model, a NaaS service
specification is needed which includes the various interfaces related to the operations offered
by a NaaS service. The NaaS service model is used when instantiating the corresponding NaaS
service. For example, in case of a VPN service instance the different service attributes used to
model a VPN service, such as tenant ID, VPN site IDs, VPN type and access bandwidth are part
of the NaaS service model and will be subsequently used by the NaaS CSC when triggering
VPN-related service requests.
– NaaS service operational policy models

A NaaS service operational policy model provides the information model related to network
operational policies for a given NaaS service. The operational policies can be created at different
levels of abstraction and can represent different types of policy rules for controlling NaaS
resources managed by the NaaS CSP. The operational policies are used to control the
configuration changes of NaaS resources (e.g., network elements).

For a given NaaS service, the corresponding NaaS service model and NaaS service operational
policy model always work together although loosely bound to each other. The creation,
deletion, and any major state changes of a specific NaaS service instance (instantiated based on
the corresponding NaaS service model selected by the NaaS CSC) usually trigger the execution
of one specific NaaS service operational policy model, which is used together with the NaaS
service model during the whole lifecycle of the NaaS service.
– NaaS resource models
A NaaS resource model reflects, in an abstract manner, NaaS CSP's resources including their
associated topological view across different layers. A NaaS resource model reflects the
attributes and operational parameters of given NaaS resources (e.g., NS, NF, virtualized

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