Support for HTTP/2 Protocol

Last updated: 2019-10-14 21:02:45


Product Content

What is HTTP/2?

  • HTTP/2 (Hypertext Transfer Protocol Version 2) is a major revision of the HTTP protocol used in web services.
  • HTTP/2 is designed to address the performance issues in HTTP1.X to make better use of network resources and reduce network application latency.
  • HTTP/2 is backward compatible with HTTP1.X.

Why should you use HTTP/2?

Compared with HTTP1.X, HTTP/2 can make a response faster and more efficient. It features the following advantages:

  • Multiplex: concurrent processing leads to a faster response.
  • Server push: the server proactively pushes the resources needed by the client, reducing the number of requests.
  • More features include traffic control, request priority, header compression, and binary framing, etc.

Product Purchase

How is CLB billed?

CLB supports the HTTP/2 protocol by default with no extra fees charged.

Product Implementation

How to enable HTTP/2 on CLB?

The listener supports HTTP/2 on HTTPS by default with no additional configuration required.
During the handshake process of HTTPS, the protocol version will be negotiated. The client uses ALPN (Application Layer Protocol Negotiation) to inform the server of a list of protocols supported. The server selects HTTP/2 or HTTP1.X according to the protocol list. It is backward compatible automatically with no additional configuration required.


  1. Plaintext HTTP/2 is not supported. Mainstream browsers and web servers only support TLS-based HTTP/2 protocol.
  2. The HTTP1.X protocol is still used between CLB and real server.

Which regions support HTTP/2?

HTTP/2 is supported in the Beijing, Shanghai, Guangzhou, Hong Kong (China), Silicon Valley, and Frankfurt regions.