Processing Diameter-to-MAP Transactions

The processing of a Diameter-to-MAP transaction involves various steps:

1. When DM-IWF receives a Request from DRL, it allocates a Pending Transaction Record (DM-IWF-PTR), starts a DM-IWF Pending Answer Timer and then forwards the unmodified Diameter Request message to a MD-IWF using the services of ComAgent.
2. When MD-IWF receives a Request message from a DM-IWF, it determines whether it can process the transaction and sends either a Success or Failure response to the ComAgent transaction.
3. If MD-IWF can process the transaction, it allocates a MD-IWF-PTR for storing the DA-MP's address and Transaction ID, converts the Diameter Request message into a MAP request message and attempts to open a MAP dialogue to the destination SS7 Node (such as HSS).
4. When MD-IWF receives the final MAP ack message closing the MAP dialogue, MD-IWF converts the MAP ack message to a Diameter Answer message. The Diameter Answer message and Transaction ID stored in the MD-IWF-PTR are sent to the DM-IWF which initiated the transaction using the services of ComAgent and the MD-IWF-PTR is deallocated.
5. When DM-IWF receives an Answer response, it uses the Transaction ID to find the DM-IWF-PTR for the transaction. If a DM-IWF-PTR is found, then DM-IWF forwards the Answer back to DRL for backward routing to the Diameter Node which initiated the transaction and the DM-IWF-PTR is deallocated. Otherwise, DM-IWF will discard the Answer.

   Note:

   If ComAgent (DM-IWF Routed Service) encounters an error or fails to receive a reliable acknowledgment from the SS7-MP to which the Request was originally sent, ComAgent can retry sending the Request to another MD-IWF (SS7-MP).