What Are HTTP/2 and HTTP/3 Protocols?
HTTP/2 and HTTP/3 are advanced versions of the Hypertext Transfer Protocol (HTTP), the fundamental application-layer protocol for the World Wide Web. As the core means of transmitting data between a client (typically a web browser) and a server, HTTP has evolved over the years to improve its performance, security, and efficiency.
HTTP/2, formally standardized as RFC 7540 in 2015, introduced several significant enhancements over the previous version, HTTP/1.1. Key features of HTTP/2 include:
- Binary framing layer. Unlike the text-based HTTP/1.1, HTTP/2 employs a binary framing layer, enabling more efficient and accurate parsing and reducing latency.
- Multiplexing. HTTP/2 supports multiple concurrent requests and responses within a single connection, reducing the need for multiple connections and improving page load times.
- Header compression. By compressing HTTP headers using the HPACK compression algorithm, HTTP/2 reduces the amount of data transmitted, leading to better performance and lower overhead.
- Server push. This feature enables a server to proactively send resources to the client's cache, even before the client requests them, resulting in faster load times.
- Stream prioritization. HTTP/2 allows clients to assign priorities to different streams, enabling servers to allocate resources more effectively and improving the overall user experience.
HTTP/3, specified as RFC 9000 in 2021, builds upon HTTP/2 and addresses the limitations of its underlying transport layer protocol, the Transmission Control Protocol (TCP). HTTP/3 replaces TCP with the Quick UDP Internet Connections (QUIC) protocol, which utilizes the User Datagram Protocol (UDP) to provide several benefits:
- Reduced connection establishment latency. To establish a connection, QUIC requires fewer round trips between the client and server, resulting in faster connection times.
- Improved congestion control. QUIC incorporates advanced congestion control algorithms that better adapt to varying network conditions, leading to more efficient data transmission.
- Connection migration. QUIC supports connection migration, allowing clients to switch between network interfaces (e.g., Wi-Fi and cellular) without interrupting the connection.
- Built-in encryption. QUIC has encryption and authentication mechanisms built into the protocol, providing improved security and privacy.
- Better handling of packet loss. QUIC's independent streams can continue data transmission even when individual packets are lost, mitigating the impact of packet loss on overall performance.
HTTP/2 and HTTP/3 are the latest iterations of the HTTP protocol, designed to enhance web performance, security, and efficiency.