Duplicate Request Flag

The setting of the "Duplicate" flag depends on the fault tolerance method chosen. If the alternate request or the hot standby option is chosen, the Duplicate field will always be set to false. If the duplicate request method is chosen, the flag will be set depending on the state of the connections. If both the side A and side B connections are OK, then requests will be sent with Duplicate set to true on one side, and set to false on the other. If one side fails, all requests will have duplicate set to false on the remaining good side. When the failed side returns to service, requests will be again marked as duplicate on one of the sides.

This flag is useful for an application that may be retaining some state on the requests. An example might be a password validation, where it is necessary to invalidate the password after a certain number of failures. The application could be written to only count the errors for requests where Duplicate is false. In that way, a user would not be charged for two errors for one failure.