How can i get chance to carry on M.S in computer science & engineering in india?

How can i get chance to carry on M.S in computer science & engineering in india?I am ga final yr engineering student.How do iits offer admission to students for M.S course?apart from iits, are there any institutes in india,offering M.S. course in engineering. If yes,then please tell me the exact admission procedure to those institutes?Is GATE exam score/rank mandatory for talking admission in M.S course? plrase help.