DNS-SRV Session Agent Recursion Error Handling

When a session request is sent from the Oracle® Enterprise Session Border Controller to a session agent, and an error response is received (or a transport failure occurs), the Oracle® Enterprise Session Border Controller attempts to reroute the message through the list of dynamically resolved IP addresses. The SBC can be configured to resend session requests through the list of IP addresses under more failure conditions.

This feature concerns the case when a session agent is configured with an FQDN in the hostname parameter and the dns-load-balance or ping-all-addresses option is configured. This configuration sets up the load balancing / redundancy behavior for the SBC to use all addresses returned in the SRV/A-record for that session agent. In previous versions of the SBC software, only when a 503 failure from the SA was received would the SBC resend the session request to the next dynamically resolved IP address (on the SRV/A record list).

By adding the recurse-on-all-failures option to a session agent, the Oracle® Enterprise Session Border Controller will resend a session request to the next address on the list after a 4xx or 5xx failure response has been received from a session agent.

If the SBC receives a failure response from the session agent, and the number of that failure is configured in the stop-recurse parameter, no further session requests will be forwarded to additional addresses from the SRV/A record list. The error message will be forwarded back to the UA.