Difference between SDN and NFV

There are some confusions surrounding the differences between SDN and NFV. Both terms relate to virtualization of network; both are hot topics these days. Sometimes, one concept is mixed with the other.

SDN stands for Software Defined Network. It is based on  two pillars.

  1. Separation of data and control plane and centralization of control plane.
  2. Programming network with open interfaces.

SDN concepts came into being while researchers were frustrated with changing   software in network elements every time they wanted to try something new to study behavior in network. They thought, why not program the network elements and manage them from central place. The language that brings this programmability to network is called “Open flow”.

NFV ( Network Functions Virtualization)  on the other hand is about virtualizing network elements by using  commodity servers so as to reduce operator’s inventory, power and space requirements and hence reduce CAPEX and OPEX.NFV is driven by operators and the concepts were put forward originally by a group of service providers through a white paper.

So what is the difference between the two?

It is commonly understood that Both SDN and NFV are totally independent from each other. This is partially true. Especially, when SDN concepts are taken, they do draw relevance from NFV. While separating control and forwarding functions and programmability are core concepts in SDN; these cannot  be achieved unless network elements become commoditized and their functions virtualized- the core concept of NFV. However it can be said that NFV can exist without depending on SDN; however, even though  network elements are commoditized but still network will not be efficient if there is no network programmability as desired in SDN. Therefore SDN and NFV help each other and if implemented together can make the network flexible, virtual and commoditized.

6 thoughts on “Difference between SDN and NFV”

  1. Hi Faisal,

    Agreed that SDN and NFV can be related but also can be treated independently. I believe that NFV is inevitable whereas SDN is more an aspiration at the moment especially in the context of a complete end to end service.
    Interesting point you make on security but I would contend that there are plenty of examples in existing telco networks of platform that if hacked could create mayhem. eg any EMS/OSS etc. So it would be the same set of risks, threats and vulnerabilities just applied to new network elements and management systems.

    1. Thanks Luke Reid for your comments.

      SDN and NFV can be complimentary but existence of one does not need the other. SDN can be a good enabler for virtualization, as in the case of data centers. Another way to say it is that NFV virtualizes equipment while SDN virtualizes networks.

  2. Hi Faisal

    The question is that de-coupling the control plane from the data plane of a given network element will not make the NE itself vanish, I mean by allowing control plane to be centralized does not necessarily mean that the NE itself has disappeared from a given network, e.g. using a comodity server as NFV concept relates, but in essence it is allowing flexibility to have the control plane embedded within this comodity server.

    So are you advocating that NFV can be achieved without SDN, but on the contrary SDN cannot be acheived without NFV?

    And that the comodity server or a group of such servers communicating with each other (M2M) will make up a future SDN architecture? Another question that comes to mind is security issues surrounding the SDN concept, I mean obviously a SDN controller being hacked will create mayhem within that particular TELCO’s network, how do we address such concerns?

    1. Thanks Ali,

      For going through the blog and raising your points.

      Agree with you. NE will not vanish. We are not talking about making NE disappear. Rather making it “cheaper”, so that you dont have to depend on the ciscos and junipers of the world, who would sell you the product with their propreitry software and then keep you locked with the upgrades and expansions, so why not think about buying your next commodity switch from the wallmart :), and then have it driven by a code written by a software-house next door.

      Well NFV and SDN are closely related. But the point is that they dont have to depend on one another for their existence. SDN can definetly be acheived without NFV and the reverse also.

      and yes security is one of the biggest concern and I am sure work is going on to address this concern. But I agree with you that the SDN networks might be prone to security vulnerabilities more, the same as the IT networks today. Also one might say that a server can be a single point of failure so we defintely have to think about redundancies in a network like based on SDN.

  3. Thanks Bruno,

    For stopping by my blog and commenting

    Yes NFV can exist without SDN. NFV is all about Virtualization and commodotization. NFV is basically aimed at reducing the cost and inventory of the hardware an operator procure. Think of NFV as a server that can realize a specific function e.g it can be a base station, RNC etc …..The advantage of using servers is to reduce the cost of the hardware and by using commodity servers this will result in huge cost savings for operators.

    Faisal

  4. Hello,
    In your paper you write “However it can be said that NFV can exist without depending on SDN”, but i’m not an expert, but i agree than SDN can exist without NFV, but NFV use SDN for control.
    Can you explain me how NFV can work without SDN ?
    Regards,

    Bruno Fleury
    bruno.fleury@essec.edu

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