Which component is typically responsible for establishing flow entries in network devices?

The component responsible for establishing flow entries in network devices is the SDN controller. In a Software Defined Networking (SDN) architecture, the SDN controller acts as the central management entity that communicates with the network devices (switches, routers, etc.) to dictate how they should handle traffic.

When a network application needs to control traffic flows, it sends its requirements to the SDN controller, which then interprets these requests and installs flow entries on the network devices. These flow entries define how specific types of traffic should be managed, including actions like forwarding, dropping, or modifying packets. The separation of the control plane (SDN controller) from the data plane (network devices) allows for dynamic and programmable network management, centralizing the decision-making process.

While other components like the data plane and network applications play roles in the operation of an SDN environment, they do not directly handle the establishment of flow entries. The data plane is primarily focused on the forwarding of packets based on the flow entries, and network applications are more concerned with requesting changes and managing network behavior rather than implementing them directly. The OpenFlow protocol serves as a communication protocol between the SDN controller and network devices, but the initiation of flow entries is specifically the responsibility of