What is HTTP/2?

HTTP/2 is the latest HTTP protocol published in May 2015. It is supported by mainstream browsers such as Chrome, IE11, Safari, and Firefox.

HTTP/2 features optimized performance, and is also compatible with the HTTP/1.1 syntax. It has features similar to SPDY. HTTP/2 and HTTP/1.1 are very different. For example, HTTP/2 is a binary protocol rather than a text protocol. In addition, it uses HPACK to compress HTTP headers, and supports multiplexing and server push.

Why is HTTP/2

  • It uses a binary protocol.
  • Header compression: HTTP/2 compresses and transfers message headers in the HPACK format and creates an index table for the headers. To send an identical header, only the index number is sent, which improves both the efficiency and speed.
  • Multiplexing: In HTTP/2, requests and responses do not have to be in matching order and an obstruction to any of the multiple concurrent requests and responses does not affect the rest. This effectively avoids the head-of-line blocking problem.
  • Server push: In HTTP/2, servers can actively push resources to clients without a request, significantly improving web page loading speeds.
  • Security: HTTPS is the trend of future, and the same goes for HTTP/2, which is based on HTTPS. Security is also an important feature of HTTP/2.

How do I enable HTTP/2?

Warning
Before enabling HTTP/2, make sure your HTTPS certificates are successfully configured.
  • If you configure HTTPS certificates for the first time, you must wait until certificate configuration is finished and the certificates take effect before enabling HTTP/2.
  • If you have already enabled HTTP/2, but your HTTPS certificate function is disabled, HTTP/2 is automatically turned off.
  1. Go to Domain Namespage, select the domain name, then click Manage.
  2. Enable the function in HTTPS Configuration > HTTP/2.