5G Architecture

Architectural Overview

The Ultra Cloud Core is Cisco's solution supporting 3GPP's standards for 5G new radio (NR) standalone (SA) mode. These standards define various network functions (NFs) based on the separation of control plane (CP) and user plane (UP), such as CUPS. This separation enhances network performance and capabilities.

Control Plane Network Functions

The Ultra Cloud Core's CP-related NFs use a common architecture with the following tenets:

  • Cloud-scale—Fully virtualized for simplicity, speed, and flexibility.

  • Automation and orchestration—Optimized operations, service creation, and infrastructure.

  • Security—Multiple layers of security across the deployment stack from the infrastructure through the NF applications.

  • API exposure—Open and extensive for greater visibility, control, and service enablement.

  • Access agnostic—Support for heterogeneous network types (for example 5G, 4G, 3G, Wi-Fi, and so on).

Control plane NFs are designed as containerized applications, such as microservices. They deploy through the Subscriber Microservices Infrastructure (SMI).

The SMI defines the common application layers for functional aspects of the NF such as life-cycle management (LCM), operations and management (OAM), and packaging.

Figure 1. Ultra Cloud Core CP Architectural Components

User Plane Network Function

The 5G UP NF within the Ultra Cloud Core is the User Plane Function (UPF). Unlike the CP-related NFs, The 5G UPF uses the same Vector Packet Processing (VPP) technology as the Cisco 4G CUPS architecture. This commonality delivers a consistent set of capabilities between 4G and 5G, such as:

  • Ultrafast packet forwarding.

  • Extensive integrated IP Services such as Subscriber Firewall, Tethering, Deep-Packet Inspection (DPI), Internet Content Adaption Protocol (ICAP), Application Detection and Control (ADC), and header enrichment (HE).

  • Integrated third-party applications for traffic and TCP optimization.

Subscriber Microservices Infrastructure Architecture

The Ultra Cloud Core (UCC) Subscriber Microservices Infrastructure (SMI) is a layered stack of cloud technologies. It enables rapid deployment and seamless life-cycle operations for microservices-based applications:

The SMI stack consists of the following components:

  • SMI Cluster Manager—Creates the Kubernetes (K8s) cluster, creates the software repository, and provides ongoing LCM for the cluster, including deployment, upgrades, and expansion.

  • Kubernetes Management—Includes the K8s primary and etcd functions, which provide LCM for the NF applications that are deployed in the cluster. This component also provides cluster health monitoring and resources scheduling.

  • Common Execution Environment (CEE)—Offers utilities and OAM functionalities for Cisco Cloud native NFs and applications. These include licensing and entitlement functions, configuration management, and telemetry. It also provides alarm visualization, logging management, and troubleshooting utilities. Also, it provides consistent interaction and experience for all customer touch points and integration points in relation to these tools and deployed applications.

  • Common Data Layer (CDL)—Provides a high performance, low latency, stateful data store, designed specifically for 5G and subscriber applications. This next generation data store offers high availability in local or geo-redundant deployments.

  • Service Mesh—Provides sophisticated message routing between application containers, enabling managed interconnectivity, extra security, and the ability to deploy new code and new configurations in low risk manner.

  • NB Streaming—Provides Northbound Data Streaming service for billing and charging systems.

  • NF or Application Worker Nodes—The containers that comprise an NF application pod.

  • NF or Application Endpoints (EPs)—The NFs or applications and their interfaces to other entities on the network

  • Application Programming Interfaces (APIs)—Provides various APIs for deployment, configuration, and management automation.

The following figure depicts how these components interconnect to comprise a microservice-based NF or application.

Figure 2. SMI Components

For more information on SMI components, see Ultra Cloud Core Subscriber Microservices Infrastructure and the related-documentation at Deployment Guide > Overview chapter.

Control Plane Network Function Architecture

Control plane (CP) NFs use a three-tiered architecture. This architecture leverages stateful or stateless capabilities in cloud native environments. The architectural tiers are as follows:

  • Protocol Load Balancer Services—These are stateless microservices that are primarily responsible for dynamic discovery of application containers as well as for protocol proxy and termination. These include traditional 3GPP protocols and new protocols that are introduced with 5G.

  • Applications Services—Responsible for implementing the core application or business logic, these are the stateless services that render the actual application based on the received information. This layer may contain varying degrees of microservice granularity. Application services are stateless.

  • State management services—Enable stateless application services by providing a common data layer (CDL) to store or cache state information (for example session and subscriber data). This layer supports various data storage technologies from in-memory caches to full-fledge databases.

Figure 3. Control Plan Network Function Tiered Architecture

The three-tiered architecture on which Cisco CP NFs are designed fully support the 5G core (5GC) Service-based Architecture (SBA) defined by 3GPP. These NFs communicate using the Service-based Interface (SBI). They use HTTP/2 over TCP, as defined by 3GPP.

Figure 4. Cisco CP NF Service-based Architecture Support

For more information on the Cisco network functions, see their corresponding network function documentation.