Hello Satyam,

IIT also called as Indian Institute of Technology is a premier institute of India that is among one of the best colleges in the world. 

The cutoff rank for M.Tech in GATE for the previous year for CS are - 

•  IIT Mumbai - 750 (general)
•  IIT Madras -  799 (general)
•  IIT Kharagpur  - 791 (general)
•  IIT Guwahati - 770 (general)
•  IIT Kanpur - 732 (general)

This is a comprehensive rank and the rank for 2019 may vary slightly but is expected to remain almost the same. 

I wish you all the best for getting into one of these IITs. Hope this helps.