The benchmark BSE Sensex today rose over 100 points in early trade on sustained buying by funds and retail investors, mainly in metal, banking, consumerdurables and realty sector stocks.Rising for the third straight session, the BSE's 30-share barometer rose by 100.86 points to 21,294.44. In the previous two sessions, Sensex had gained 161 points.The wide-based National Stock Exchange index Nifty also edged higher by 18 points to 6,332.In the Asian region, Japan's Nikkei gained 0.38 per cent, while Hong Kong's Hang Seng rose by 0.47 per cent in early trade today.