The Schlieffen plan was a plan to win a swift victory over France, by engaging massive military German forces and invading Belgium and Luxembourg, in order to overwhelm French defensive capabilities. The idea was that the implementation of such plan would force the French army into a decisive battle that it would lose and Germany would be able to dictate favorable conditions to a shocked French republic.
The plan was devised by Field Marshal Alfred von Schlieffen. It did not yield all the expected results. Although France suffered heavy losses, Germany was unable to stop the strategic, fast retreat of French forces to heavily defended positions and the war evolved into a very long trench was of attrition.
In my view, speed was the only way such plan would have worked. Had the Germans used all the mechanized troop transportation systems it could muster, the French army would have been encircled and cut from its strategic rear and the Germans would have forced them into surrendering.
