Hi Naazira Badar
SDN as the name suggest is defining network in software and when we do that it makes our network flexible as the packet can be routed according to demands and as there is a controlling keeping an eye on the paths that r idle it can make better use of resources and channels and hence lead to better optimization of resources. It has revolutionised the world as it can make the existing networks flexible. I hope it provides the necessary information u require.
Best Regards
Burhan