Which of the following solutions is designed to switch traffic to an alternative processing node?

A load balancer is specifically designed to distribute incoming network traffic across multiple servers or processing nodes. This function ensures that no single server becomes overwhelmed with too much traffic, thereby maintaining optimal performance and availability. When one node experiences high demand or fails, the load balancer can seamlessly redirect traffic to an alternative processing node, ensuring that user requests are fulfilled without disruption.

In contrast, a router primarily directs data packets between networks based on their IP addresses, facilitating communication between different network segments. While it plays a crucial role in traffic management, it does not specifically provide the functionality for redistributing or switching traffic across processing nodes.

A switch operates within a local area network to connect devices, forwarding data packets based on MAC addresses, but it does not handle the distribution of traffic between different processing nodes like a load balancer does.

A firewall serves to protect network resources by monitoring and controlling incoming and outgoing traffic according to predetermined security rules. While it can indirectly influence traffic flow, it does not actively switch traffic between processing nodes.

Thus, the unique capability of the load balancer to redirect traffic to alternative servers makes it the most suitable answer to the question.