Which protocol is used for spoke-to-spoke connectivity when using Secure Private Access (SPA) and SD-WAN?

The correct choice, IPSEC, is widely recognized for establishing secure connections across public and private networks, including between spokes in a Secure Private Access (SPA) environment combined with SD-WAN. IPSEC provides the necessary encryption and integrity for the data being transferred between endpoints, ensuring that communications remain confidential and free from tampering.

In the context of SD-WAN (Software-Defined Wide Area Networking), IPSEC is especially useful because it allows for secure direct communication between branch offices or remote sites (the spokes) without needing to route traffic through a central hub. This not only enhances performance by reducing latency but also optimizes bandwidth usage, making IPSEC a favored choice for secure spoke-to-spoke connectivity.

While other options such as HTTPS, L2TP, and GRE may serve different purposes or are applicable in other networking contexts, they do not offer the same level of security for the type of direct connectivity required in this scenario. HTTPS is primarily used for secure web traffic and wouldn’t typically be used for site-to-site connectivity. L2TP (Layer 2 Tunneling Protocol) often needs additional security protocols, like IPSEC, which diminishes its stand-alone efficacy in this specific application. GRE (Generic Routing Encapsulation) is a tunn