There are two different types of dust collection, high velocity and conventional dust collection.
High velocity vacuum moves low CFM (example 50 CFM, 75 CFM, etc.), but at a terrific velocity or air speed (normally 8,000 FPM). High velocity vacuum is done in small pipes and hoses (i.e. 1″ or 2″). It is designed to lift dirt from carpets, etc.
Conventional dust collection moves a lot of air in larger pipes and hoses (4″, 5″, 6″, etc.) at a velocity sufficient to keep material flowing to the dust collector (normally at 4,000 FPM). This type of dust collector moves large quantities of air necessary to evacuate dust hoods on machinery.
Summary: If you try to pull vacuum through a 1 ½” diameter hose on a conventional dust collector, it will be like sucking a milk shake through a cocktail straw.
If you attach 2″ hose from a high velocity vacuum to a planer hood with a 5″ outlet, you will not evacuate the hood. The two sciences do not overlap. They must be treated separately.