Question

What are the key challenges in Software Defined Networks (SDN). How will you migrate from a traditional network to an SDN based network?

Answer 1

The key challanges faced in Software Defined Networks (SDN) are as follows
1) Scalability
        -Scalability has been proven one of the major challange faced by SDM
        -Two sub issues can be derived from this single challange are as follows
                - Controller scalability
                - Network-node scalability
        -One controller can handle till 6Million flows per second.
        -So, this proves that either one or multiple controllers are able to administer services required for
         a wide number of data forwarding nodes
        -To increase scalability, the logically-centralized controller must be physically distributed
        rather than operating on a peer-to-peer basis
        
2)Flexibility and Perfomance
        - Flexibility refers to the capability possessed by networks to adjust to new and un precedented
        features such as
                -Apllication services
                -Network services
        -Perfomance deals with the speed at which network nodes at the data plane process information
        from the control plane
        -General purpose processors provide the highest flexibility while application specific standard
        products lay the foundation for high-perfomance networks
        -the SDN data plane and this is currently being incorporated into SDN products.
        
3)Security
        - SDN is widely adopted and deployed, thus security must put into consideration
        - In SDN, the controller is a target for threats especially when open to unauthorized access.
        - Attack on controller can cause serious damage to network,as it is responsible for controlling the entire network
        -Transport layer security would provide required security aimed at reducing these threats due to authentication
        between controllers and their switches
        -Thus SDN architecture supports a high level security system
        
4) Interoperability
        - Here we focus on the challanges faced in migration from traditional to SDN network
        - Deploying entire new infrastructure based on SDN technology would be enough  and for this, all network elements and devices would be
        SDN-enabled
        - There is a tremendous base of networks supporting imperative systems and organizations
        - Transitioning these networks into new architecture is impossible as it is only targeted at infrastructure-based networks such as campus networks 
          and data centers

        -In traditional router or switch architecture, both the control and data plane function on a single device.
        -Software-defined networking is a network model that has been developed to virtualize the network.
        -In the SDN control plane from the data plane is separated in a network device.
        -SDN controller performs all complex functions at other hand data plane is responsible for forwarding traffic flows
in SDN architecture