What does a "Session Border Controller" (SBC) do?

A Session Border Controller (SBC) plays a crucial role in managing voice over IP (VoIP) communications and ensuring seamless connectivity and security between different elements of a network. In the context of 3CX and remote clients, the SBC acts as an intermediary that protects the network from potential threats and ensures that the communication flow is reliable and efficient.

SBCs handle various tasks such as signaling management, encryption, and protecting against denial-of-service (DoS) attacks. They can also help with NAT traversal, enabling devices behind firewalls to communicate effectively. By establishing secure connections, an SBC guarantees that data packets of voice calls are transmitted safely between endpoints, improving the overall quality and security of VoIP traffic.

The other options provided do not accurately reflect the primary functions of an SBC. While billing management, bandwidth regulation, and call traffic direction can be part of broader VoIP system operations, they are not specifically the responsibilities of a Session Border Controller.