What are the main differences between an Mtech,ME and MS courses in India?

Hi, i'm currently studying for Gate.

I've been having this doubt for a long time, since the Mtech,ME,MS are considered equivalent courses then why the difference in name?
Is there a difference in the syllabus or what you study?
Is there a difference in the duration of the courses?
What are the advantages and disadvantages of each course?

I've heard Mtech is superior to ME and MS is more research oriented, is it true?
Can i get into research later on even if i take up an Mtech?