There were mainly five rounds
2 Technical
1 Technical by MD
1 Managerial
1 HR
Questions were asked from Data Structures, C, C++, Puzzles.
They also asked about final year project and individual projects done.
For me these interviews increased with difficulty for every round. Some of my peer also had 6 rounds of interviews. For others, they asked Java, OS, Unix, DBMS.
The interviews were from the slotted time till evening.
For me, they went well. As long as you know the answers well and answer confidently it will go easily. Also, if you don't know any answer, be truthful as i'm sure value honesty as much as knowledge. But be sure to know other answers as well.