@raman07 I think you are totally confused. Since i took Airtel FTTH connection in september, let me clear your doubts...
1. 100 mbps is only available on FTTH(Fibre) line. V-Fibre is just VDSL with 40 mbps max...
100mbps has been available on VDSL over 2 months now. It started from Chennai / Hyderabad but is available majorly (North) since last 2 weeks provided the loop length from the area Exchange is less than 250m. All those who have max attainable speeds of 110+mbps can anytime upgrade to it for as low as 1099+taxes