The minimum required speed is 56 kbps. You should opt for that internet connection that provides you with minimum guaranteed speed. Do not pay too much attention on the maximum speed claimed. It is the stability of speed which is important in virtual classroom. You may test your internet connection here at different times to check its stability.

PS: Some of the virtual classrooms that we use work at 28.8 kbps dial-up modem but 56 kbps is fine for all virtual classrooms that we use and hence 56 kbps is the requirement that we officially state. We have chosen the technologies which are the best and most suitable for both within India and outside India.