SDN and NFV are different but complementary. SDN controls how traffic flows. NFV virtualizes what processes the traffic.
SDN provides: Centralized control, programmable forwarding, dynamic path selection, automated provisioning.
NFV provides: Virtualized functions, flexible deployment on commodity hardware, rapid scaling.
Combined benefits:
SDN steers traffic to VNFs dynamically
NFV orchestrator requests network connectivity
SDN controller provisions paths instantly
Service chains reconfigure in seconds
A new customer's virtual firewall and load balancer spin up. SDN creates paths automatically.