The Bombay Stock Exchange benchmark Sensex today rose by over 81 points to 17,441 points on buying by funds in auto and consumer durables stocks. The Sensex was trading at 17397, up by 36 points when reports last came in. The wide-based National Stock Exchange index Nifty was trading at 5187, up by 8 points.Brokers said fresh buying activity picked up on optimism over the global economic recovery and robust December quarter earnings for domestic companies. They added, mixed cues from other Asian markets also influenced the trading sentiments in the domestic market.