How will SDN impact NMS ?

Now-a-days we hear repeatedly that SDN is going to rule the future in Networking.

As SDN and OpenFlow have emerged as a new paradigm of networking, let us see what is SDN first? 

As per Wikipedia,

Software-defined networking (SDN) is an approach to computer networking which evolved from work done at UC Berkeley and Stanford University around 2008.^[1] SDN allows network administrators to manage network services through abstraction of lower level functionality. This is done by decoupling the system that makes decisions about where traffic is sent (the control plane) from the underlying systems that forwards traffic to the selected destination (the data plane). The inventors and vendors of these systems claim that this simplifies networking.^[2]
 

In order to make a simple explanation, it is just decoupling control plane functionality from the forwarding plane.

Also, it is very important to understand what is a SDN controller all about?

SDN Controller is just an application which sits in Controller layer as per the SDN layered architecture. SDN controller has the major job to control the flow so that it acts as an intelligent network using OpenFlow.
BTW, OpenFlow is a communications protocol that gives access to the forwarding plane of a network switch or router over the network.

Then what is SDN controller? Is it same as NMS ?

Of course, not exactly!! But it has got some features of it, I would say.

Though SDN controller has certain management capabilities, it is separate from "NMS Orchestration & Services applications" which sit on top of SDN controller in the logical hierarchy. 

There is no super cool open source NMS/OSS application which can be easily integrated with SDN controllers even though many SDN controllers provide a platform for management of services.

We should have a major goal in mind, to have the entire network behaves as desired. Hence, implementing an end-to-end network management system with required application suite is a challenge for many CSP Operators @ NOC.

SDN is a only conceptual approach, there are 2 parts in SDN.

1.       SDN Applications

2.       SDN Infrastructure

I googled and found that there are many SDN applications and SDN infrastructure vendors in worldwide, but unfortunately not many leaders in India. 

Many big telcos are in the market for competition, ALU, Ericsson, Huawei, HP etc..

I found there are open source SDN Controller applications also, out of which "OpenDayLight" impressed me on its Technical Overview.

It again depends on the Controller application’s features and benefits one would get from it.

Some people claim that NMS/OSS application sits in the Controller layer and others say it is application layer. But whatever it is, I feel tomorrow it will be an integrated product suite with Traffic Engineering, NMS, OSS, Provisioning, Asset/Inventory Management etc.. and make the SDN controller to perform the tasks better.

Okay, now coming to the main discussion. 

Will NMS die if SDN controller does all the management and controlling functionality? 

Of course not, you need to align to make sure you have all the features are available for you to have a desirable network. I would recommend BSS/OSS/NMS should be integrated with the SDN controller and make the network much more intelligent. If you are a NMS vendor, you should think how to integrate with the SDN controllers. 

What do you mean by integrating SDN-C with NMS ?
Any SDN Controller will provide a NBI (North Bound Interface) API, hence using your NMS/Any Management utility application and integrate with the SDN-C.

Also, there are huge opportunities in developing applications in the NETWORK ORCHESTRATION AND SERVICES LAYER. Based on your need, you can think of developing a small Traffic Engineering or Performance Analysis app which would make sense for intelligent networking.

For more details on Overview of SDN : 
https://www.opennetworking.org/sdn-resources/sdn-library/whitepapers

Hence, let us wait and watch how the networking world is going to migrate to SDN!!!