HTTP/2 features, support and release date

HTTP/2 features, support and release date

HTTP/2 (originally named HTTP/2.0) is the second major version of the HTTP network protocol used by the World Wide Web. It is based on SPDY. HTTP/2 is being developed by the Hypertext Transfer Protocol working group of the Internet Engineering Task Force. HTTP/2 would be the first new version of HTTP since HTTP 1.1, which was standardized in RFC 2616 in 1999. The Working Group presented HTTP/2 to IESG for consideration as a Proposed Standard in December 2014, and IESG approved it to publish as Proposed Standard on Feb 17, 2015.

After more than two years of consideration, the Internet Engineering Task Force (IETF) has finally approved HTTP/2. HTTP/2 is made up of two specifications: The new protocol itself, and HPACK, which provides header compression for HTTP/2. This revised protocol "will help provide faster user experience for browsing, reduce the amount of bandwidth required, and make the use of secure connections easier".

HTTP/2 is based in part on an earlier protocol called SPDY (pronounced speedy) from Google, and takes most of its speed improvements from it. There was never a competition between the two; SPDY is HTTP/2's father, not its rival.

Why is HTTP/2 better?

In a few words: HTTP/2 loads webpages much faster, saving everyone time that otherwise would go to waste. It's as simple as that.

HTTP/2 improves speed mainly by creating one constant connection between the browser and the server, as opposed to a connection every time a piece of information is needed. This significantly reduces the amount of data being transferred. Plus, it transfers data in binary, a computer's native language, rather than in text. This means your computer doesn't have to waste time translating information into a format it understands. Other features of HTTP/2 include "multiplexing" (sending and receiving multiple messages at the same time), the use of prioritization (more important data is transferred first), compression (squeezing information into smaller chunks) and "server push," where a server makes an educated guess about what your next request will be and sends that data ahead of time.

See also:

Tips to increase WiFi signal strength

Differences from HTTP 1.1

The proposed changes do not require any changes to how existing web applications work, but new applications can take advantage of new features for increased speed.

HTTP/2 leaves most of HTTP 1.1's high level syntax, such as methods, status codes, header fields, and URIs, the same. The element that is modified is how the data is framed and transported between the client and the server.

Additional performance improvements in the first draft of HTTP/2 (which was a copy of SPDY) come from multiplexing of requests and responses to avoid the head-of-line blocking problem in HTTP 1 (even when HTTP pipelining is used), header compression, and prioritization of requests.

Goals

• Support common existing use cases of HTTP, such as desktop web browsers, mobile web browsers, web APIs, web servers at various scales, proxy servers, reverse proxy servers, firewalls, and content delivery networks.
• Server push technologies
• Loading page elements in parallel over a single TCP connection
• Fixing the head-of-line blocking problem in HTTP 1
• Maintain high-level compatibility with HTTP 1.1 (for example with methods, status codes, and URIs, and most header fields)
• Negotiation mechanism that allows clients and servers to elect to use HTTP 1.1, 2.0, or potentially other non-HTTP protocols.

Browser support

• Chrome supports HTTP/2 by default. As of February 2015, Google plans to fully implement HTTP/2 in future versions of its Chrome browser, effectively dumping support for SPDY.
• Internet Explorer supports HTTP/2 in version 11, but only for Windows 10 beta, and is enabled by default. Currently only HTTP/2 over TLS is implemented.
• Opera supports HTTP/2 by default.
• Firefox supports HTTP/2 which has been enabled by default since version 36. Experimental support for HTTP/2 was originally added in version 34. Currently only HTTP/2 over TLS is implemented.

So when will we get to enjoy the benefits of HTTP/2?

There's no real start date for the use of HTTP/2, and many people may already be using it unknowingly. The draft submitted on February 11th will expire in six months (August 15th, to be precise). Before expiring, it has to be confirmed and become a finished document, called an "RFC," or a new draft with changes has to be published.

The HTTP/2 technology is already baked into many web servers and browsers, even if it's still just a draft. For example, Microsoft supports HTTP/2 on Internet Explorer under the Windows 10 Technical Preview; Chrome also supports it (while it's disabled by default, you can easily enable it); and Mozilla has had it available since Firefox Beta 36.