This is me taking note on HTTP/2.
What is the problem with HTTP/1.1 ?
Modern websites requires lots of resources. And resources are communicated through TCP, and TCP is slow in starting, because it required key value exchanges, three way hands shaking etc. And we call that RTT (Round Trip Time).
Some uses KeepAlive flag to keep single connection and use this single connection with multiple resources. But this also have problem, because when one resource takes up time, all resources behind the line gets stuck.
With TCP/1.1, it made it possible to have 6 instances of resources to be handled at same time.
What people try to do within limitation of HTTP/1.1.
6 is better than 1 but demand for resources to travel over http exceed 6 times more, so people had to come up with ways to reduce request over http.