Hi,
In Simple words if I define
MRP is calculates gross requirements based on sales orders and Independent Requirements ( PIR)
CBP is based on past consumption values and uses the forecast or other statistical procedures to determine future requirements. the net requirements calculation is not triggered either by planned independent requirements or dependent requirement. Instead, it is triggered when stock levels fall below a predefined reorder point or by forecast requirements calculated using past consumption values.
For rest go through this link which will helps you in understanding the difference
For Materials Requirements Planning
http://help.sap.com/saphelp_sbo2005asp1/helpdata/en/ac/25563e33854d5db3d6a352150bf6ba/content.htm
http://help.sap.com/saphelp_sbo2005asp1/helpdata/en/07/c51ac8c6724eb8adf1b342fcc4497d/content.htm
For Consumption-Based Planning :
http://help.sap.com/saphelp_erp2005vp/helpdata/en/7d/c27097454011d182b40000e829fbfe/frameset.htm
rgds
gsc
