Network Functions Virtualisation (NFV) Release 3; Virtualised Network Function; Specification of the Classification of Cloud Native VNF implementations

The present document focusses on the characterization of Virtualised Network Functions (VNF) as part of their configuration and deployment in "the Cloud". Such VNFs are assumed to be implemented using generic cloud computing techniques beyond virtualization [i.1]. For example, the VNFs can be built with re-usable components as opposed to a unique - and potentially proprietary - block of functions.
 
Cloud native VNFs are expected to function efficiently on any network Cloud, private, hybrid, or public. The VNF developer is therefore expected to carefully engineer VNFs such that they can operate independently in the desired Cloud environment. Cloud environment can be implemented based on hypervisor/VM or container technology. This is an indication of the "readiness" of VNFs to perform as expected in the Cloud. The objective of the present document is to develop the characterization of the "Cloud Readiness" of VNFs.
 
From an operator perspective, it is essential to have a complete description of cloud native readiness of VNFs; this description will help operators in their VNF selection process. To do this, it is essential that a set of non-functional parametric characterizations be developed that appropriately describe the cloud native nature of VNFs. Non-functional parameters describe the environmental behaviour of VNFs residing in the Cloud. They do not describe the actual working functions of the VNF; rather they describe how the VNF can reside independently in the Cloud without constant operator involvement.
 
The present document considers not only the "pure" cloud native VNF implementations (e.g. no internal resiliency or state) but also some transition implementations to cloud native such as the VNFs with internal resiliency.
 
Non-functional characteristics of a cloud native VNF are described through a VNF Product Characteristic Descriptor (VNFPCD) created by the VNF provider. Usage of the cloud native VNFPCD is as follows:

• The cloud native VNFPCD is used by an operator to decide on what VNF product to deploy to fulfil a particular functionality, when the decision is based on non-functional parameters.
• The VNFPCD can be used in a VNF market place for a standardized description of the VNF products non- functional characteristics and as such can be checked/searched for automatically.

The intent of the present document is to identify a minimum set of non-functional parameters by which VNFs are characterized as cloud native. The non-functional parameters are classified according to the specific environmental behaviour of the VNF.
 
Each behaviour then provides a list of specific non-functional parameters along with specific requirements such that the cloud native nature of the VNF can be satisfactorily established.