Connection Failure Detection
The Oracle Communications Core Session Manager detects that a connection between itself and a given HSS has failed if either a diameter request fails or the diameter DWR/DWA handshake fails. If the HSS does not respond to five requests, the Oracle Communications Core Session Manager marks that HSS as out of service.
The Oracle Communications Core Session Manager forwards unacknowledged messages to subsequent HSSs based on strategy. It changes the destination host AVP of these messages and marks then with the T flag. The HSS recognizes the T flag as an indication that the request may be a duplicate, caused by a problem in the network.
Periodically, the Oracle Communications Core Session Manager attempts to establish diameter connections with out of service HSS servers. When those connections succeed, the Oracle Communications Core Session Manager marks the HSS as in-service and resumes using it within the context of the configured redundancy and load balancing strategy.