You will have to give the entrance test for M.PHIL/PH.D. And for that you will have to meet the below provided enfilibility criteria -

ME/M.Tech in relevant field of Engineering with a minimum CGPA of 6.5 or not less than 60% for General Category and for SC/ST/OBC minimum CGPA of 6.0 or not less than 55% marks at Master’s level or any other equivalent qualification recognized by the Institute (OR)
BE/B.Tech with valid GATE scores, also the candidates shall have a minimum CGPA of 8.0 or not less than 75% for General Category/OBC and for SC/ST minimum CGAP of 7.5 or not less than 70% at BE/B Tech level.