Round Robin

What is Round-robin?

Round-robin is a method in which system resources are utilized in a sequential manner. For example, when a computer with a single CPU executes multiple processes simultaneously, the CPU time is divided into small "time slices" (or time quanta), which are allocated to each process sequentially. This method, where all processes are treated equally and handled in turn, is called round-robin.

Round-robin is also used in load balancing for web servers and similar systems. A prominent example is DNS round-robin, which leverages DNS servers. In this approach, the mapping between hostnames and IP addresses is changed for every user request, distributing requests to servers with the corresponding IP addresses in a round-robin fashion. This ensures that all user requests are treated equally and the server resources are allocated sequentially.

While simple and easy to implement, this method has certain drawbacks:

• It can't account for differences in server load, which may lead to overloading certain servers.
• It cannot detect server failures, so requests may still be directed to non-functional servers.
• Configuration updates, such as adding new servers, take time to propagate and may result in outdated information being used.

Due to these limitations, DNS round-robin is becoming less common, with more advanced load balancers being adopted instead. Modern load balancers offer enhanced features and processing power for more effective load distribution and uninterrupted operation during server failures.

F5 provides the F5 BIG-IP Local Traffic Manager, a comprehensive solution for efficient load balancing and reliable operations.