NFV Overview and Problem

Network Functions Virtualisation (NFV) Definition

NFV is a concept of network architecture that uses virtualization technology to divide the functions of the network node hierarchy into several functional blocks, which are implemented in software middleboxes and are no longer limited to hardware appliances. NFV is recognized as the primary means of next-generation network architecture due to its open, flexible standardization, and low management cost [1].

Reference Fig 1 Traditional Network Function and Virtual Network Function [2]

Network Functions (NFs)

The traditional network functions (NFs) (e.g., firewall, load balancing, and intrusion detection system) produced by the network service suppliers generally run on the dedicated hardware appliances.

Problem Traditional Network Functions

• The development life cycle is long as the network-enabled applications are required to be designed with high quality, high stability, and strict protocol support.
• The flexibility is poor as some specific network functions rely heavily on the specialized hardware appliances.
• The mutability of the demand of users makes it hard for the dedicated hardware appliances to adapt to its frequent changes.
• There is no unified standard for virtualization technology, which makes the network functional hardware appliances produced by different manufacturers differ from each other.

NFV Architecture

Reference Fig 2 NFV architectural framework [3] [4]

The NFV architectural framework addresses the limitations of traditional network functions by introducing Virtualized Network Functions (VNFs), which run on standard hardware. This approach enables more flexible, scalable, and cost-efficient management. NFV-MANO (Management and Orchestration) plays a key role in orchestrating and managing the lifecycle of VNFs through its three main components: the NFV Orchestrator (NFVO), the VNF Manager (VNFM), and the Virtualized Infrastructure Manager (VIM). The separation of VNFM and VIM allows better abstraction and modular control over virtual resources and services

Use Case Virtualization and Softwarization of Mobile 5G Network

In the 5G architecture, the combination of SDN and NFV is often seen as a powerful and flexible solution. Network functions are implemented as Virtualized Network Functions (VNFs), and these VNFs are typically deployed across edge cloud nodes to ensure low latency and scalability.

Reference Fig 1 VNF virtualization architecture and CNF Cloud Architecture [8]

Let’s consider a simple scenario:

• 10 edge cloud sites
• 10 VNF instances for the control plane
• 10 VNF instances for the user plane

In this case, the system runs smoothly. A single VNFM and VIM are sufficient to manage the deployment and operation of all VNFs.

The Problem with Scalling NFV

However, as we scale the network, the architecture begins to reveal its limitations. Imagine a larger-scale deployment:

• 5000 edge cloud nodes
• 5000 VNF instances for the control plane
• 5000 VNF instances for the user plane Using a single VNFM and a single VIM to manage such a deployment becomes a critical bottleneck. All deployment requests, resource monitoring, status updates, and orchestration decisions must go through these two central entities.

Reference

• [1] https://www.etsi.org/deliver/etsi_gs/NFV-MAN/001_099/001/01.01.01_60/gs_NFV-MAN001v010101p.pdf
• [2] https://link.springer.com/article/10.1007/s11276-021-02741-9
• [3] https://ieeexplore.ieee.org/document/7045396
• [4] https://info.support.huawei.com/info-finder/encyclopedia/en/NFV.html
• [5] https://www.researchgate.net/publication/319978814_5G_IoT_Industry_Verticals_and_Network_Requirements
• [6] https://www.researchgate.net/publication/315095751_Network_Slicing_for_5G_with_SDNNFV_Concepts_Architectures_and_Challenges