SDN security is managed near the perimeter of the network with firewalls, VPNs, and IPS, and traditional networking security policies are created based on telemetry data.

SDN exposes an API to configure locally per device for security policies, and traditional networking uses northbound API for network admin interface for configuring security policies.

SDN creates a unified control point making security policies consistent across all devices, and traditional networking must be configured device by device, leaving room for error.

SDN devices communicate with each other to establish a security policy, and in traditional networking, devices communicate upstream to a central location to establish a security policy.