The Sensex is trading up by 312 points at 19, 829 on persistent buying, mainly in IT, metal, tech, auto and consumer durable sectors. The Sensex resumed higher at 19,585 and firmed up further to 19,823 before quoting at 19,829 a short while ago.The NSE 50-share Nifty also rose by 108 points to 5,888.