HTTP/2 is the latest version of the HTTP protocol. It improves the efficiency of resource access. This topic describes the concepts and benefits of HTTP/2 and explains how to configure it.
Background information
HTTP/2, also known as HTTP 2.0, provides new features compared with HTTP 1.1, such as multiplexing, header compression, request prioritization, and server push. HTTP/2 resolves the performance issues of HTTP 1.1, optimizes request performance, and is compatible with HTTP 1.1 semantics. HTTP/2 is supported by browsers such as Google Chrome, Internet Explorer 11, Safari, and Mozilla Firefox.
HTTP/2 has the following benefits:
Binary protocol: Unlike HTTP 1.x, which is text-based, HTTP/2 splits all transmitted information into smaller messages and frames and encodes them in a binary format. This binary format makes the protocol more extensible. For example, frames can be used to transmit data and instructions.
Content security: HTTP/2 is typically implemented over HTTPS to provide enhanced security. The performance improvements of HTTP/2 help offset the overhead that is associated with HTTPS encryption.
Multiplexing: On a single connection, a browser can send multiple requests at the same time, and the server can return responses concurrently. Multiplexing also supports stream dependencies. This feature allows the client to inform the server which resources are more important so that they can be transmitted with a higher priority.
Header compression: HTTP request headers contain a large amount of information and are often sent repeatedly. HTTP/2 uses the HPACK format for compression. The client and server each cache a header table. For subsequent requests with identical headers, only the index is sent. This improves efficiency and speed.
Prerequisites
Before you enable HTTP/2, ensure that an HTTPS certificate is configured for the domain name. For more information, see Configure an HTTPS certificate.
If you are configuring an HTTPS certificate for the first time, you must wait for the certificate to take effect before you can enable HTTP/2.
If you disable the HTTPS certificate feature after you enable HTTP/2, HTTP/2 is automatically disabled.
Procedure
Log on to the ApsaraVideo VOD console.
In the navigation pane on the left, under Configuration Management, click CDN Configuration > Domain Names.
Find the domain name that you want to configure and click Configure.
Click the HTTPS tab and turn on HTTP/2.