As far as i know. Ceasefire is informal cessation of hostilities on the battlefield just in one front. To collect dead bodies and stuff. World War 1 had lots of this. Most notably altough called Christmas Truce it was practically a ceasefire on Western Front of WW1. Armistice is immediate cessation of all hostilities on all fronts in a form of a treaty. Since peace talks may take a long time armistice provides the transitional period between war and final peace treaty. They may have include some pro-defensive clauses. Like allowing occupation (not annexation) of some defensible mountain passages or river crossings (most notably Rhine) to victors. And always enforces demobilization of the losing side. Truce is the final treaty after a war. All demands of the victors are satisfied with truce. Annexations and war reparations etc are decided and after implemented with truce.