A Quick Look at QUIC*
The design of QUIC is described in detail, with a focus on the fundamental underpinnings of its most important concepts, including its combination of connection and security setup, use of IP address independent connection identifiers and persistent connection state, and its tight coupling with applications.
Abstract
QUIC represents the latest transport protocol development with the potential to replace TCP over time. Instead of describing the QUIC operations mechanically by enumerating, step-by-step, how it works, this paper aims to explain QUIC from the core ideas that its design is based on. We first describe TCP, the first deployed transport protocol and the most widely used so far, to explain the basic functions performed by a transport protocol and the issues observed from the TCP operations; we also discuss the insights learned from the design of a few other transport protocols. Then, we describe the design of QUIC in detail, with a focus on the fundamental underpinnings of its most important concepts, including its combination of connection and security setup, use of IP address independent connection identifiers and persistent connection state, separate window mechanisms for congestion control and data delivery reliability, and its tight coupling with applications, demonstrating how these new design features effectively address the identified issues in the existing transport protocols.