Error Handling and Status Codes

Error handling in SMPP follows a status code mechanism. Each SMPP response PDU includes a command_status field, which indicates whether the request was successful or failed due to an error.

SMPP follows a request-response model, where each request PDU sent by the client (ESME) receives a corresponding response PDU from the server (SMSC). 
In SMPP, sending a submit_sm PDU results in a submit_sm_resp PDU containing a success or failure status.
This mechanism ensures that every request has a matching response, allowing the client to track message delivery status, errors, and session events.