HTTP/2 is the latest version of HTTP. HTTP/2 provides more secure and efficient access to resources. This topic introduces the concept and benefits of HTTP/2, and describes how to use HTTP/2.


An SSL certificate is configured. For more information, see Configure an SSL certificate.
  • Before you enable HTTP/2, we recommend that you wait until the certificate takes effect. This applies if you configure an SSL certificate for the first time.
  • If you disable SSL certificates after your enable HTTP/2, HTTP/2 is automatically disabled.

Background information

HTTP/2, originally named HTTP/2.0, is the latest version of HTTP. Compared with HTTP/1.1, HTTP/2 supports more features. For example, multiplexing, header compression, request prioritization, and server push are supported. HTTP/2 provides optimized performance and is compatible with HTTP/1.1 semantics. It is supported by all major browsers such as Google Chrome, Internet Explorer 11, Safari, and Mozilla Firefox.

Benefits of HTTP/2:
  • Binary encoding: HTTP 1.x is used to parse data into text. However, HTTP/2 is used to split the data to be transmitted into messages and frames, and encode them into binary formats. Binary encoding can be used to ensure that HTTP/2 is more scalable. For example, frames can be introduced to transmit data and instructions.
  • Content security: HTTP/2 is designed based on HTTPS. This ensures content security and network performance.
  • Multiplexing: HTTP/2 allows multiplexing of multiple concurrent streams through a single connection. For example, a browser can be used to initiate a large number of requests in parallel through one connection. Then, the responses to these requests are returned at the same time. In addition, stream dependencies can be configured. This allows a client to provide further details of prioritized streams to the server by using the same connection. This way, important content can be delivered in priority.
  • Header compression: HTTP headers support large volumes of information. Each request and each response are transmitted at the same time as these headers. HTTP/2 can be used to compress HTTP headers into the HPACK format. After HTTP/2 is enabled, both ends of a connection cache a copy of HTTP header indexes. Therefore, index numbers can be transmitted to identify duplicate HTTP headers. The system does not need to transmit these HTTP headers. This increases the transmission speed and efficiency.


  1. Log on to the Alibaba Cloud CDN console.
  2. In the left-side navigation pane, click Domain Names.
  3. On the Domain Names page, find the domain name that you want to manage and click Manage in the Actions column of the domain name.
  4. In the management pane of the domain name, click HTTPS.
  5. In the HTTP/2 section, turn on HTTP/2.