Implementation Guide › Architectural Considerations › Architectural Use Cases › Redundancy and High Availability › Agent to Policy Server Communication › Failover

Failover

Failover is the default HCO setting. In failover mode, a Web Agent delivers all requests to the first Policy Server that the HCO lists and proceeds as follows:

1. If the first Policy Server does not respond, the Web Agent deems it unavailable and redirects the request, and all subsequent requests, to the next Policy Server that the HCO lists.
2. If the first two Policy Servers do not respond, the Web Agent deems both of them unavailable and redirects the request, and all subsequent requests, to the next Policy Server that the HCO lists.

Note: For more information about configuring an HCO with multiple Policy Servers, see the Policy Server Configuration Guide.

If an unresponsive Policy Server recovers, which the Web Agent determines through periodic polling, the Policy Server is automatically returned to its original place in the HCO list and begins receiving all Web Agent requests.

The following diagram illustrates the Web Agent failover process: