Confusing about NFV implementation (Network Functions Virtualization)

Question

I'm researching about SDN and NFV.

In the concept of NFV on Wikipedia , it says : "Network Functions Virtualization (NFV) is a network architecture concept that proposes using IT virtualization related technologies, to virtualize entire classes of network node functions into building blocks that may be connected, or chained, together to create communication services."==> first thing to consider that it will reduce the cost of facilities.

So in real life implementation, for example, how can we virtualize a network nodes like a router?

NFV was created for the networks to be capable to extend in a dynamically way(virtualize the router) , not a static way(buy a new router), that is we must implement the router functions in the server or a computer instead of buying and then adapting the new router to the current nextwork , in this case I don't see any different in this implementation , because buying a server to implement a virtualized router is not cheaper than buying a new router.

Can anyone explain this for me , or Am i wrong understanding the NFV concept?

Thanks.

Answer 1

SDN is just that, software defined networking. In a Hybrid SDN model SDN decouples the logic from the physical box, rendering the physical box a simple "forwarding" box. The logic rests with the SDN controller where developers create APIs that manage these forwarding boxes (we call them network elements now) with flow tables that get pushed to them. The benefit here is that the devices can now be configured and provisioned through this controller, as opposed to having to log into each and every box.

Then you have the cloud. A small office can literally get away with porting all of their apps and services into the cloud, doing away with most of their physical boxes. Of course you still need a LAN in the office and a way to get out to the Internet and eventually the cloud. You can even ask the cloud provider to provision load-balancing on specific applications, firewalls and content delivery services. So basically your office applications and most of the supporting LAN and databases can be safely ported to cloud providers.

Answer 2

When you said "...because buying a server to implement a virtualized router is not cheaper than buying a new router", it depends: As it's a virtualized resource, you can use this new server to run your router and another resource from your infrastructure, if the machine has more hardware capacity than you need for a single router.

In fact, you might not even need to buy a new machine, if you have your resources in a cloud like AWS (or your own private cloud), when you have need for more routers, you can just flexibly allocate more hardware resources and spawn a new router instance (scale out) and, whenever your router demand is lower than what you have allocated, you can reduce your number of routers (scale in) and stop losing money with an infrastructure that you are not using at the moment.

Consider that a really high level explanation, if you want to know the details about how a Virtual Network Function scales in and out in a NFV implementation, I recommend you to read the ETSI specification about how it should work: http://www.etsi.org/standards-search#page=1&search=&title=1&etsiNumber=1&content=0&version=1&onApproval=1&published=1&historical=0&startDate=1988-01-15&endDate=2017-04-13&harmonized=0&keyword=&TB=789,,832,,831,,795,,796,,800,,798,,799,,797,,828&stdType=&frequency=&mandate=&collection=&sort=3

Answer 3

Let me continue with your example of the router. Traditionally, these routers are vendor specific. For example, the major sellers are companies like Cisco, Juniper, etc. They are implemented on proprietary hardware and therefore if you want to buy a new router you need to buy from them only. Further, when they go into some problems, you need a dedicated engineer to repair them. Therefore, the telecommunication has to take care of high Capital Expenditure (COPEX) and Operational Expenditure (OPEX).

With NFV, the entire router function is implemented as a software and deployed on a general purpose servers (GPP) or cloud. These GPPs are relatively very cheap when compared to proprietary hardware. Thanks to cloud computing, even small companies can afford servers on Amazon and Google clouds. Because of cheap availability, COPEX is now relatively cheaper. Further, you don't need a dedicated engineer when the hardware goes into a problem, the same engineer who works for GPP server maintenance is enough. This way OPEX is reduced.

Now imagine, like routers there are many networking elements present in Telecommunication. If every networking element requires a dedicated engineer, how much a Teleco operator will be spending money. Apart from this, due to software implementation, suppose, when you have very high traffic than expected, you can just roll out a new router (software network function) on GPP or Cloud instead of completely buying a new router, which is very costly. As you already know, in the cloud you pay based on usage.

There are many more uses. To know more you need to read research papers.