A broad topic that at minimum means connecting to the systems of vendors or customers so the systems themselves can communicate for stock checks, order placement, etc. In earlier times EDI or direct connections with custom interfaces were used. XML Internet transactions are expected to replace the older methods as XML offers the benefits of real-time transactions.
In the broadest sense SCM can include demand planning, order promising, strategic network optimization, production scheduling, transportation planning, transportation execution, tracking, measuring and performance management.