Hi Surya,
Best practices for flow of data from ECC --> SAP MII --> Shop floor & Vice verse:
1. Send ECC data through IDOC's/RFC's as messages to SAP MII message listener and BSL transaction process data and update directly on shop floor database as if you configured in Data services or later send those data by web service to shop floor system (i.e. depends on Shop floor machines).
From Shop floor:
shop floor --> SAP MII --> ECC
1. Use either Web service or fetch data from DB and pass data to BAPI's for sending to ECC through BLS transaction.
Regards,
Praveen Reddy