NFV (Network Function Virtualization)

This is an introductory article about NFV. An article about SDN, which is closely-related, will be completed shortly.
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Definition of NFV (with special note about Linux)

NFV (Network Function Virtualization) is using virtual machines to provide network functions.

If this sounds strange, remember that many services we associate with network hardware can be provided by the Linux Operating System. Examples include:
  • NAT (Network Address Translation)
  • firewalls (iptables)
  • DNS
  • Routing ( click here for introductory document on Linux Policy Routing)

Note that Cisco’s Enterprise NFV is based on Linux.

Benefits of NFV

By using virtual machines, NFV uses standard x86 computers to reduce reliance on dedicated network equipment. These x86 computers are often referred to as “commodity” machines in the literature about NFV.

This allows administrators to quickly add services by “spinning up” virtual machines. the number of Virtual Machines can also easily be reduced if the demand for network services decreases.

Enterprise NFVIS
Cisco's NFV product, called Enterprise NFVIS, provides a GUI front end for deploying network services.  Screen shots are shown on the right:
  1. Opening Screen. Click Deploy on Left to start adding elements to your network.
  2. Adding a network service.
  3. Add Router: Drag icon from left. You can give the router a name.
  4. Completed network during deployment.

Vocabulary
Compute domain: NFVI domain that includes servers and storage
IND (Infrastructure Network Domain): NFVI domain that includes all networking that interconnects compute/storage infrastructure. These include network resources, virtual networks, other virtualization layer options, control and administrative agents.
N-Pop (Network point of presence): A location where a network function is implemented as either a PNF (physical network function) or a VNF (virtual network function)
Network service: a composition of network functions such as DNS, printing, World Wide Web, DNS, time services.
NF (Network Function): Usually refers to a physical network appliance or node; has well-defined external interfaces and and well-defined functional behavior.
NFP (Network Forwarding Path):  Ordered list of connection points and associated policies that implement VNF (Virtualized Network Function) logical interfaces
NFV (Network Functions Virtualization): Virtualization of network functions. Principal of using virtual hardware abstraction to separate network functions from the hardware they run on.
NFVI (Network functions Virtualization infrastructure): The hardware and software components that make up the environment in which VNFs (Virtualized Network Functions) are deployed.
NFVI-Node: physical devices that are managed as one entity.
NFVI: Network Functions Virtualisation Infrastructure
PNF (physical network function): Typically a proprietary system; a tightly coupled software and hardware system
Virtual machine: a virtualized host
Virtual network: a computer network that consists, at least in part, of virtual network links. A virtual network link is a link that does not consist of a physical (wired or wireless) connection between two computing devices but is implemented using methods of network virtualization.


Suggestions for Future Learning

William Stallings: Foundations of Modern Networking

SDN by Nadeau, Thomas D. and Ken Gray, published by O'Reilly. (chapter 11) 

ETSI etsi.org  
Welcome Page

NFVIS: Opening Screen

NFVIS: Create Network

NFVIS: Adding Router

NFVIS: Deploying Completed 

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Welcome Page