OpenFlow is a protocol that enables communication between a controller and a switch in a software-defined networking (SDN) architecture. It allows the controller to remotely manage and control the forwarding plane of the switch, which is responsible for packet forwarding. By using OpenFlow, the controller can define how the switch should handle different types of network flows, and deploy rules and actions to the switch’s flow table. This way, the controller can implement more flexible and dynamic network policies than traditional methods, such as access control lists (ACLs) and routing protocols.
OpenFlow is used for various purposes, such as:
• Network innovation and experimentation: OpenFlow allows researchers and network operators to test new network protocols and applications without modifying the hardware or firmware of the switches. They can use OpenFlow to create virtual networks that run on top of the physical network, and experiment with different network behaviors and scenarios.
• Network security and management: OpenFlow enables centralized and fine-grained control over network traffic, which can improve network security and performance. For example, OpenFlow can be used to implement firewall, intrusion detection, load balancing, quality of service (QoS), and traffic engineering functions on the switches.
• Network virtualization and slicing: OpenFlow can create multiple logical networks that share the same physical infrastructure, but have different characteristics and requirements. This can increase network utilization and efficiency, as well as support different network services and applications. For example, OpenFlow can be used to isolate different tenants or users on a cloud network, or to provide different levels of reliability and latency for different types of traffic.