Which technology creates an overlay to connect remote sites over commodity links while improving performance, security, and reducing cost?

SD-WAN (Software-Defined Wide Area Network) is correct because it specifically addresses the need to connect remote sites over diverse, often commodity (e.g., broadband internet) links, while prioritizing performance, security, and cost reduction. It achieves this by abstracting the network hardware and allowing centralized, policy-based management of traffic, dynamic path selection, and integrated security. InfiniBand is incorrect; it's a high-throughput, low-latency interconnect technology primarily used in data centers for server-to-server and server-to-storage communication, not for wide-area connectivity. VTEP (VXLAN Tunnel Endpoint) is incorrect; it's a component within VXLAN that encapsulates/decapsulates Ethernet frames, but VXLAN itself is a tunneling protocol for data centers, not a comprehensive solution for wide-area site interconnection with performance and security optimizations. VXLAN is incorrect for the same reason as VTEP; it's a data center overlay technology, not an SD-WAN solution.