What is the most important problem solved by sdn?

In 2009, Professor Mckeown formally put forward the concept of SDN. SDN adopts the idea of layering, separating logic control from data forwarding, forming a logic control plane and a data forwarding plane. In the control layer, it includes a logic centralized and programmable controller, which can control the global network information and facilitate operators and researchers to manage the network and deploy new protocols. In the data layer forwarding layer, the switch only provides simple data forwarding function, which can quickly process matching data streams and adapt to the increasing traffic demand. The control layer and the data forwarding layer interact through a unified interface, and the controller sends instructions to the switch through this interface, and the switch only needs to perform corresponding actions according to these instructions. Compared with the traditional network, SDN reduces the equipment load, which is more conducive to assisting operators to manage infrastructure and reduce operating costs.