What is the best for classroom

There are several that come to mind, although your low bandwidth connection may pose an issue with that many individual clients. It would be easier with just two clients connected to large displays than it would be to have 10 clients on that connection. As far as software:

Cisco WebEx
Go To Meeting
Office 365
InterCall Unified Meeting

They all have a monthly charge however.
 
thanks for your replay.

Can I find a solution that is using server to server connection.

I want to set a server in my classroom it will broadcast video to all students.
 


There are solutions like that, but they are costly ($1000-$10,000USD). What is your budget?