What is bull whip effect and what is the relationship in terms of information technology to SMDC - suppliers , manufacturers , distributor&customers?

Bullwhip effect : Parent company or manufacture have to maintain a plan to prepare the goods according to the considerations of end user and they have to manage their stocks.

Use of Information technology connects supplier or manufacture to Customers by the channel of distribution  they have to use some apps which are easily accessible for everyone (distributors,Suppliers & Customers)