What is the QUIC protocol? Why was it invented?

QUIC (Quick UDP Internet Connections) is a transport protocol developed by Google and standardized by the IETF, which operates over UDP. Its main goal is to reduce delays during connection establishment and improve data transfer performance on the internet.

Why was QUIC invented:

• TCP requires several handshake rounds to establish a connection, which increases latency. QUIC combines connection setup and TLS encryption into a single process, reducing the time to the first byte.
• QUIC operates over UDP, allowing to bypass restrictions and improve flow control and multiplexing, avoiding the "head-of-line blocking" problem in TCP.
• Built-in encryption support and improved packet loss management.

Example: when loading a webpage via HTTPS using QUIC, the browser can start transmitting data faster than with traditional TCP+TLS, enhancing the user experience.