Which of the following is a function of a switch?

A switch primarily functions to connect devices within the same network while intelligently filtering traffic based on MAC address information. This ability allows the switch to send data only to the intended recipient device, reducing unnecessary network congestion and improving overall efficiency. By maintaining a MAC address table, the switch can make quick decisions on where to forward incoming frames, ensuring that the specific device receives the information intended for it.

The other functions listed are typically handled by different types of network devices. Encrypting data for secure transmission is more aligned with the roles of security appliances or specific software solutions rather than switches. Load balancing involves distributing network or application traffic across multiple servers or pathways, which is generally managed by load balancers or routers rather than switches. Lastly, acting as a firewall is a function associated with security devices that monitor and control incoming and outgoing network traffic based on predetermined security rules, rather than a core role of a switch.