Hi Whitestar,
Thanks for the reply.
I am thinking of shortlisting c20i. I feel even if I buy C7 which is around 7k, the technology will become obsolete in a couple of years and new one will come up (just like SD,HD,FullHD,4k,ulta,....)
By the way, I am using TpLink TD w8961ND on BSNL...