Describe the main roles of the communication layer, the network-wide state-management layer, and the network-control application layer in an SDN controller.

1.

Role of communication layer:

-it has the responsibility of transferring information among network controlled devices.

-it provides up to date view of the state of the network to SDN controller which shows that a new device has being added to the network as well as the link that was attached being non-existent.

2.

Role of network wide state management layer:

-it is responsible for the controller having the network's state information

-it also helps in the making of ultimate control decisions.

c

role of network control application layer:

- It is responsible for the reading and also the writing of the state of the network as well as flow tables which are in the layer of state management.

- It also notifies of changes such as state-event change. this helps to take actions with regards to the event notification.

system programmer option d is correct

because an operating system is software that manages computer hardware and system resources.