Installation Guides › Implementation Guide › Architectural Considerations › Architectural Use Cases › Redundancy and High Availability › Agent to Policy Server Communication › Round Robin Load Balancing

Round Robin Load Balancing

Round robin load balancing is an optional HCO setting. Round robin load balancing distributes requests evenly over a set of Policy Servers, which:

• Results in more efficient user authentication and authorization
• Prevents a single Policy Server from becoming overloaded with Agent requests

Note: For more information about configuring an HCO for round robin load balancing, see the [set the co variable for your book].

In round robin mode, an Agent distributes requests across all Policy Servers that the HCO lists. An Agent:

1. Sends a request to the first Policy Server that the HCO lists.
2. Sends a request to the second Policy Server that the HCO lists.
3. Sends a request to the third Policy Server that the HCO lists.
4. Continues sending requests in this way, until the Agent has sent requests to all available Policy Servers. After sending requests to all available Policy Servers, the Agent returns to the first Policy Server and the cycle begins again.

If a Policy Server does not respond, the Agent redirects the request to the next Policy Server that the HCO lists. If the unresponsive Policy Server recovers, which the Agent determines through periodic polling, the Policy Server is automatically restored to its original place in the HCO list.

The following diagram illustrates the round robin process:

More information:

Multiple Components for Operational Continuity

Clustered Components for Scale