Online whiteboard using WebRTC -- 2

We require online whiteboard using WebRTC in our e-learning website. Through our website, students take private lessons from their tutors. The online whiteboard will be used when tutors teach their students. 1. Online whiteboard client program: see the attached descriptions. If you have better functions, layouts or graphic design than ones of the whiteboard sketch, you can propose me. 2. Signaling server - node.js or Java - The sigaling server needs to communication with the existing Tomcat server on which e-Learning website is running. (For example, getting participants information, getting lesson information, etc) - The server needs to take the limited users based on the setting data of DBMS - I'd like to know maximum concurrent users of the online whiteboard You can test it and get the result or let me know how to test it * There should be no license issue in service