An SAP Business Suite system is base on SAP NetWeaver. As of SAP NetWeaver version 7.0, SAP Business Warehouse is part of SAP NetWeaver itself, which means a BW system exists inside SAP Busiess Suite system such as ERP(ECC 6.0 or higher). This BW system is referred to as an "embedded BW system".
DXC does not require BW on SAP HANA. Also with DXC, data is not loaded into the embedded BW system. Instead, data is redirected into SAP HANA.
DXC internally in HANA uses the ICM ( internet connectivity manager ) --- receives XML packages over http connection.
Mechanism written on the XS Engine( special component for HANA )
-- receives data packets from ICM, converts format
-- Insert the records into the activation queue of the in-memory DSO
-- Activation processing --> records are go into the active table in proper sequence
SAP HANA Direct Extractor Connection
原文：http://www.cnblogs.com/grantliu/p/4127658.html