A remote AP uses which type of secure tunnel to communicate with a controller?

A remote AP (Access Point) utilizes IPSec (Internet Protocol Security) for establishing a secure tunnel to communicate with a controller. IPSec is a suite of protocols designed to secure Internet Protocol communications by authenticating and encrypting each IP packet in a communication session. This is especially important for remote access scenarios, as it ensures that data transmitted between the AP and the controller remains confidential and tamper-proof.

Using IPSec provides a robust mechanism for creating a secure, encrypted tunnel over potentially insecure networks, such as the internet. It supports various encryption protocols and provides data integrity and authentication, making it well-suited for scenarios where an AP needs to connect back to a central controller securely and reliably.

In contrast, while SSL (Secure Sockets Layer) and SSH (Secure Shell) are also used for secure communications, they are not primarily designed for this specific application in wireless networking. L2TP (Layer 2 Tunneling Protocol) can be combined with IPSec, but it does not provide encryption on its own. Therefore, choosing IPSec is the most fitting choice for the secure tunnel requirement for remote APs in Aruba network environments.