H2 is an acronym that stands for Hypertext Transfer Protocol version 2 (HTTP/2). It is a major revision of the Hypertext Transfer Protocol (HTTP) and the most recent version of the protocol used to communicate between browsers and web servers. It is an application layer protocol that is used to transfer data between a client and a server.
HTTP is the protocol that is used to access web pages. It is the set of rules that allow two computers to communicate and exchange information over the Internet. When you type in a URL or click on a link, your web browser sends a request to a web server, which then responds with the requested page or file.
The new version of the protocol, HTTP/2, was designed to provide faster loading of web pages and more efficient data transfer. The biggest changes that HTTP/2 brings are multiplexing, header compression, server push, and improved security.
Multiplexing
Multiplexing is a technique that allows multiple requests to be sent and received simultaneously over the same connection. With HTTP/1.1, each request had to be sent one at a time, and the response had to be waited on before the next request could be sent. This process was slow and inefficient, leading to longer page loading times.
With HTTP/2, multiple requests can be sent over the same connection, allowing for faster loading of web pages. This greatly improves the performance of web applications and websites, as the browser does not have to wait for the server to respond before sending the next request.
Header Compression
Header compression is another feature of HTTP/2 that improves the performance of web applications and websites. In HTTP/1.1, each request and response had to include a header, which contained information about the request. This header was always the same size, regardless of the size of the request or response.
With HTTP/2, the header is compressed, which reduces the amount of data that needs to be sent and received. This reduces the amount of time it takes to load a page, as less data needs to be transferred.
Server Push
Server push is an advanced feature of HTTP/2 that allows a server to proactively send data to the client before the client requests it. This is useful for applications and websites that require multiple resources to be loaded, as the server can push the resources to the client in one request, rather than having the client send multiple requests for each resource.
Improved Security
HTTP/2 also improves the security of web applications and websites, as it requires all data to be encrypted. This helps to protect data from being intercepted and read by malicious actors.
Conclusion
HTTP/2 is the latest version of the protocol used to access web pages. It brings improvements to the performance of web applications and websites, including multiplexing, header compression, server push, and improved security. These features help to make web applications and websites faster and more secure.