Which of the following is a method commonly used to automatically balance server loads?

Round robin is a widely used method for automatically balancing server loads by distributing incoming requests evenly across multiple servers in a sequential manner. This approach ensures that each server receives a fair share of the workload over time, preventing any single server from becoming a bottleneck.

In a typical round robin setup, as requests come in, they are sent to servers in the order they are listed, looping back to the first server after reaching the last one. This method is straightforward and efficient, as it does not require knowledge of the current load or performance of the servers, which makes it easy to implement in many environments.

The other methods listed may be relevant in specific contexts but do not serve the primary function of balancing server loads in the way round robin does. For instance, statistics-based routing takes into account the current load and performance metrics, which can complicate the process. Sequential routing simply sends requests in a set order without the balancing logic of round robin. Direct allocation, on the other hand, involves designating specific resources for specific tasks, which does not inherently balance the load across multiple servers.