The CNFs must only require “Vanilla Kubernetes” with no additional plug-ins for basic operation. The optional use of plug-ins for performance optimization is allowed to enable mission critical telecommunication services
A fundamental principle of a Cloud Native Network Function (CNF) is to decompose software into smaller, more manageable pieces.
This is a design pattern that strives to structure an application as a collection of loosely coupled stateless services and stateful backing services.
The automation of scaling enables the self-dimensioning of applications. Life Cycle Management (LCM) of each microservice.- Manual or Kubernetes Horizontal Pod Autoscaler (HPA) for the automatic scaling.
Therefore, a CNF supports any combination of failures at any time without escalation to full restart and loss of service.
Multiple failures lead to capacity degradation, but no degradation of service availability. Service is provided as long as one instance of each required microservice type is available.
The degradation of capacity is addressed by self-healing scaling, enabling a system to recover quickly and automatically.
Some Examples of CNF’s Automated Actions Are:
1. Auto-scaling of Micro-Services
Kubernetes orchestration scales the services based on the rise or fall in the demand for individual services. Kubernetes enforces the limits and triggers for scaling set by the application
2. Auto-Healing (Application Resiliency)
Kubernetes monitors health and terminates or starts Pods if services fail because of hardware or software faults.
3. Update and Upgrade
software versions are implemented with updated Pods orchestrated by Kubernetes to deploy the update.
4. Redundancy(Resiliency)
1+1 physical redundancy
5. Scaling
Eeither manually or Kubernetes HPA Horizontal Pod Auto scalar.
6. Orchestration and Automation
Trying to cover all the necessary automation only in Network Function Virtualization Orchestration (NFVO) and connected specific VNF managers is not practical due to the number of automation flows that need to be managed and coordinated.
The answer to this challenge is hierarchy and delegation. The automation logic moves down the stack, freeing up the higher layers (NFVO, Service Orchestration) from simpler tasks that can be automated in lower layers (Kubernetes).
Handling the automation only on the internals of a CNF is not enough. It is equally important that the CNF can be orchestrated from an external management system to be included in a wider network context like an ETSI Network Service or a 3GPP network slice, or both.
SBA (Service-Based Architectures)
Service-based architectures have been in use in the software industry to improve the modularity of products.
A software product can be broken down into communicating services. With this approach, the developers can mix and match services from different vendors into a single product.
Service-oriented architecture (SOA) is a software design approach where application components offer services to other elements over a network via a communication protocol.
This architecture’s principles are vendor, product, and technology-independent. Each service in SOA is a distinct functionality unit, accessible remotely and can be independently managed and updated.
An example of such a service could be the online retrieval of a credit card statement.
