Introduction

The Cisco PCF has a three-tier architecture which consists of Protocol, Service, and Session tiers. Each tier includes a set of microservices (pods) for a specific functionality. Within these tiers, there exists a Kubernetes Cluster comprising of Kubernetes (K8s) master, and worker nodes (including Operation and Management nodes).

For high availability and fault tolerance, a minimum of two K8s worker nodes are required for each tier. You can have multiple replicas for each worker node. Kubernetes orchestrates the pods using the StatefulSets controller. The pods require a minimum of two replicas for fault tolerance.

The following figure depicts a PCF K8s Cluster with 12 nodes – 3 Master nodes, 3 Operations, and Management (OAM) worker nodes, 2 Protocol worker nodes, 2 Service worker nodes, 2 Session (data store) worker nodes.

PCF Kubernetes Cluster
Note
  • OAM worker nodes - These nodes host the Ops Center pods for configuration management and metrics pods for statistics and Key Performance Indicators (KPIs).

  • Protocol worker nodes - These nodes host the PCF protocol-related pods for service-based interfaces (N7, N28, N36, and NRF) and Diameter Rx Endpoint.

  • Service worker nodes - These nodes host the PCF application-related pods that perform session management processing.

  • Session worker nodes - These nodes host the database-related pods that store subscriber session data.