HTTP/2 is the latest version of HTTP. HTTP/2 enables more efficient access to resources. This topic describes the concept and benefits of HTTP/2. This topic also describes how to enable HTTP/2.

Background information

HTTP/2 is also called HTTP 2.0. Compared with HTTP 1.1, HTTP/2 provides new features such as multiplexing, header compression, request priority setting, and server push. HTTP/2 resolves the issues in HTTP 1.1, optimizes the request performance, and is compatible with the semantics of HTTP/1.1. HTTP/2 is supported by browsers such as Google Chrome, Internet Explorer 11, Safari, and Mozilla Firefox.

HTTP/2 has the following benefits:
  • Binary encoding: Unlike HTTP 1.x that parses data into texts, HTTP/2 splits the data to be transmitted into messages and frames and encodes them into binary formats. Binary encoding makes HTTP/2 more scalable. For example, frames can be introduced to transmit data and instructions.
  • Content security: HTTP/2 is designed based on HTTPS and ensures content security. You can use HTTP/2 to minimize performance degradation that is caused by using only HTTPS.
  • Multiplexing: HTTP/2 allows multiplexing of multiple concurrent streams on a single connection. Specifically, you can initiate countless requests at the same time over one connection by using a browser. The server responds to these requests at the same time. In addition, you can set stream dependencies, which the client uses to inform the server of the importance of a given stream relative to other streams on the same connection. This ensures that resources are appropriately allocated.
  • Header compression: HTTP headers carry large volumes of information, which is repeatedly transmitted. HTTP/2 compresses HTTP headers into the HPACK format. Both ends of the communications cache a copy of the HTTP header indexes and hence transmit only index numbers for duplicate HTTP headers. This increases transmission speed and efficiency.


An HTTPS certificate is configured before you enable HTTP/2. For more information, see Enable HTTPS secure acceleration.

  • If you are configuring an HTTPS certificate for the first time, you must wait for the certificate to take effect before you enable HTTP/2.
  • If you disable HTTPS certificates after you enable HTTP/2, HTTP/2 is automatically disabled.
  1. Log on to the ApsaraVideo VOD console.
  2. In the left-side navigation pane, click Configuration Management.
  3. Choose CDN Configuration > Domain Names.
  4. On the Domain Names page, select the domain name that you want to configure, and click Configure in the Actions column.
  5. Click HTTPS and turn on HTTP/2.