Quick UDP Internet Connections is an transport layer network protocol designed by Jim Roskind at Google, initially implemented in 2012.
- Dramatically reduced connection establishment time
- Improved congestion control
- Multiplexing without head of line blocking
- Forward error correction
- Connection migration
QUIC is a new transport which reduces latency compared to that of TCP. On the surface, QUIC is very similar to TCP+TLS+HTTP/2 implemented on UDP. Because TCP is implemented in operating system kernels, and middlebox firmware, making significant changes to TCP is next to impossible. However, since QUIC is built on top of UDP, it suffers from no such limitations.
QUIC supports a set of multiplexed connections between two endpoints over UDP, and was designed to provide security protection equivalent to TLS/SSL, along with reduced connection and transport latency, and bandwidth estimation in each direction to avoid congestion. QUIC’s main goal is to improve perceived performance of connection-oriented web applications that are currently using TCP.
Google is already using QUIC on its major sites.