Role of Communication layer in an SDN controller:
• Communication layer is responsible in transferring information among SDN controller and controlled network devices.
• It helps in providing the up-to-date view of the network’s state to the SDN controller like messages indicating that new device has joined the network and attached link does not exists no longer.
Role of Network-wide state-management layer in an SDN controller:
• Network-wide state-management layer responsible in controller having the networks state information.
• All the up-to-date information about the SDN controlled devices like hosts, switches, etc., is helpful in making the ultimate control decisions.
Role of Network-control application layer in an SDN controller:
• Network-control application layer is responsible in read/write of the network state and flow tables which are within the state-management layer.
• It is also responsible for the notifications when state-event change occur, which in turn helpful in taking actions from the SDN-controlled devices with response to network event notifications.
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