OpenFlow actions tell the switch what to do with matched packets. Actions execute in order.
Output actions: Forward to physical port, send to controller, flood to all ports.
Header modification: Set source/destination MAC or IP, set VLAN ID, set DSCP for QoS, decrement TTL.
Metering actions: Apply rate limiting, mark or drop excess traffic.
Group actions: Send to multiple ports (multicast), load balance, failover to backup.
You can chain actions. Match HTTP traffic, rewrite the destination IP, decrement TTL, and forward to port .