Detailed Study Notes on Network Function Virtualization (NFV)

Chapter 3: Network Function Virtualization (NFV)

### Author: Rami Tawil

Evolution from Hardware-Based to Virtualized Network Functions

  • Traditional networks relied on proprietary hardware appliances for each network function.

    • Examples of such hardware appliances include:

    • Routers

    • Firewalls

    • Load balancers

    • Intrusion detection systems

  • Scaling and upgrading traditional networks required costly physical installations.

Transition to NFV

  • NFV replaces dedicated hardware with software-based Virtual Network Functions (VNFs) that run on commodity servers.

  • Benefits of this transition include:

    • Improved flexibility

    • Enhanced scalability

    • Greater cost-efficiency

Motivation and Advantages of NFV

  • Key motivations for adopting NFV:

    • Reduce dependency on proprietary network hardware.

    • Lower capital (CAPEX) and operational (OPEX) costs.

    • Enable rapid deployment of new network services.

    • Increase scalability through on-demand resource allocation.

    • Simplify management and automation using orchestration frameworks.

    • Enhance innovation by decoupling software from hardware vendors.

Problem Statement

  • Complex carrier networks often feature a large variety of proprietary nodes and hardware appliances, creating several challenges:

    • Launching new services becomes difficult and time-consuming.

    • Space and power requirements lead to inefficiencies.

    • Additional hardware varieties require integration, complicating operations and increasing costs.

    • Rapid technology advancements lead to quicker end-of-life for existing hardware due to the procure-design-integrate-deploy cycle.

    • Traditional network models depend on specific hardware and software, resulting in one physical node per role.

NFV Use Cases

  • NFV supports several applications including:

    • 5G Networks: Enables core network functions (EPC, AMF, SMF) to be virtualized.

    • Cloud Services: Supports flexible and scalable virtualized data centers.

    • Internet of Things (IoT): Facilitates resource management for billions of connected devices.

    • Enterprise Networks: Allows deployment of virtual firewalls, VPNs, and load balancers as needed.

NFV Architecture and Standards

  • The ETSI NFV Architectural Framework outlines the core components of NFV architecture:

    • NFVI (Network Functions Virtualization Infrastructure)

    • VNFs (Virtual Network Functions)

    • MANO (Management and Orchestration)

  • The framework also includes interfaces and reference points for communication among components.

NFV Management and Orchestration

Key Components

  1. NFV Orchestrator

    • Central automation engine responsible for managing the end-to-end lifecycle of network services which involve multiple VNFs.

    • Coordinates resource management across the NFV infrastructure.

    • Key functionalities:

      • Network Service Lifecycle Management

      • Instantiation: Utilizes a blueprint (Network Service Descriptor) for creating, connecting, and launching VNFs in the required order.

      • Scaling: Adjusts service capacity based on traffic demands (e.g., more virtual firewall instances during peak loads).

      • Healing: Initiates recovery actions for failed services (restarting VNFs, migrating to healthy servers).

      • Update/Upgrade: Manages coordinated software upgrades across services without downtime.

      • Termination: Cleanly shuts down services and frees up resources.

      • Resource Orchestration & Global Inventory

      • Maintains a global resource inventory (compute, storage, network) across multiple locations.

      • Makes informed decisions on VNF placement (e.g., proximity to users).

      • Policy Management and Enforcement

      • Implements business policies such as Service Level Agreements (SLAs) and security policies.

  2. VNF Manager (VNFM)

    • Manages the lifecycle of individual VNF instances.

    • Responsibilities include:

      • Instance Lifecycle Management:

      • Receives requests from NFVO to create and manage VNFs.

      • Executes scaling, healing, updating, and termination requests for VNFs based on NFVO or direct triggers.

      • Configuration and Event Reporting: Manages VNF configurations and collects performance data.

      • Interaction with VNF and EMS: Communicates with VNF management systems for configuration and health reporting.

  3. Virtualized Infrastructure Manager (VIM)

    • Controls the NFV Infrastructure (NFVI), which consists of compute, storage, and networking resources.

    • Key responsibilities include:

      • Resource Discovery and Inventory: Maintains real-time resource inventory.

      • Orchestration of Virtual Resources: Manages creation and connection of VMs and networks.

      • Performance and Fault Management: Monitoring of NFVI performance and detecting faults.

      • Image Management: Stores software images used for instantiating VNFs.

      • Network Policy Implementation: Enforces low-level connectivity and security policies derived from higher-level requirements.

Functional Interactions

  • The different component interfaces in the NFV architecture are mapped out, showing their interactions:

    • NFV Orchestrator ↔ VNF Manager (Or-Vnfm)

    • VNF Manager ↔ VIM (Vi-Vnfm)

    • NFV Orchestrator ↔ VIM (Or-Vi)

    • OSS/BSS ↔ NFV Management (Os-Ma)

Interaction with OSS/BSS

  • Integration with OSS/BSS is crucial for service-related processing:

    • Customer Service Request via BSS: Customer orders a VPN service online.

    • BSS captures customer orders and manages interactions.

    • Service Order Handling by OSS: Translates orders into technical parameters and communicates with NFVO.

    • Automation of Deployment: NFVO orchestrates the service provision process guided by requests from OSS/BSS.

  • Benefits of OSS/BSS integration:

    • Automated service delivery

    • Improved time-to-market for new services

    • Seamless system integration

Real-World Example

  • A detailed example illustrates the interaction of OSS/BSS with NFV components, such as activating service based on customer requests.

OSS, BSS, and EMS Functions

  • The roles of OSS, BSS, and EMS are distinguished:

    1. OSS: Manages overall network operations.

    2. BSS: Manages customer interactions, orders, and billing.

    3. EMS: Manages individual devices or functions.

Standardized Interfaces Between Functional Blocks

  • Interfaces provide structured communication among the ETSI NFV framework components, enhancing interoperability.

Technical Insights

  • The technical specifications detail how components like NFVO, VNFM, and VIM interact through APIs to orchestrate network services.

  • Technical examples include REST API calls and data formats used in different interactions.

Application and Performance Monitoring

  • Applications focus on real-time performance metrics monitoring, resource optimization, and automated fault tolerance measures to maintain high service quality.

Security in NFV

  • Discusses the inherent security challenges in virtualization and how to address them through strategies like VNF isolation and secure orchestration.

NFV in 5G and Edge Computing

  • Role of NFV in supporting 5G architectures and utilizing network slicing for resource optimization.

  • Examples include the deployment of edge services and integration with Multi-access Edge Computing (MEC).

Differences Between NFV, SDN, and Cloud Computing

  • Clarification on the distinct roles and functionalities of NFV, SDN, and Cloud Computing, highlighting their complementary nature in modern network architectures.