If this a supply chain question? Or more from a Technology planning perspective?
If supply chain, then IBP is all about brining together finance, supply chain, marketing/sales teams together to work on a common view of supply & demand.
Tactical DP is doing demand forecasting on a short-term horizon, typically in isolation with the business (marketing, sales, finance etc).
Feel free to write to me if you want help in understanding the supply chain world.