HTTP2 is a new version of HTTP developed by the HTTPbis working group.
It is the first update in approximately 17 years since HTTP / 1.1 established in 1999, and it is mainly developed to improve performance.
Main features of HTTP / 2
HTTP / 1.1 used to exchange requests and responses in text format, but
HTTP / 2 makes it possible to efficiently transfer information by using a binary format called frame.
HTTP / 1.1 can send and receive only one request and response pair at a time, which is a performance issue.
In HTTP / 2, multiple virtual pipelines called streams can be launched, and requests and responses
can be exchanged within each stream, so multiple sets of transmission and reception are possible at the same time. This will improve performance. The client can also inform the server side of the stream priority.
Header compression, Since the HTTP header compression method has been changed to a method that extracts only the headers that need to be sent as a difference and sends it, the transfer amount is reduced.
Even if there is no request from the server push client, the required files can be determined on the server side and sent to the client in advance.