QUIC vs UDP vs TCP: A Detailed Comparison

What is QUIC？

QUIC (Quick UDP Internet Connections) is a protocol developed by Google that is built on top of UDP (User Datagram Protocol). It aims to provide a faster and more reliable alternative to TCP (Transmission Control Protocol) for modern web applications.

QUIC includes features such as stream multiplexing, congestion control, and encryption, which makes it ideal for modern web applications. It also includes built-in error correction mechanisms that ensure data is transmitted without errors and in the correct order.

QUIC is designed to reduce the latency of internet communication, which is particularly important for mobile devices and real-time applications such as gaming and video streaming. By reducing the number of round trips required to establish a connection, QUIC can significantly improve the performance of web applications.

QUIC is now supported by all major web browsers, including Chrome, Firefox, and Safari. It is expected to become the dominant protocol for internet communication in the future.

What is UDP？

UDP (User Datagram Protocol) is a protocol used for internet communication. It is a connectionless protocol, which means it does not establish a connection before data transmission.

UDP is a faster protocol than TCP (Transmission Control Protocol), as it does not have to perform the three-way handshake. However, it is an unreliable protocol that does not guarantee the delivery of data, nor does it ensure it is transmitted in the correct order.

UDP is ideal for applications that require low-latency, such as online gaming, video streaming, and VoIP. These applications prioritize speed over reliability, and the occasional loss or out-of-order delivery of data is acceptable.

UDP is also used for certain types of network discovery and broadcasting, as well as for time-sensitive applications that can tolerate some level of data loss.

What is TCP？

TCP (Transmission Control Protocol) is a protocol used for internet communication. It is a reliable protocol that ensures data is transmitted in the correct order and without errors.

TCP is a connection-oriented protocol, which means it establishes and maintains a connection between the sender and receiver before data transmission. This process involves a three-way handshake, which ensures both parties are ready to transmit and receive data.

TCP is ideal for applications that require error-free and ordered data transmission, such as web browsing, email, and file transfer. It is slower than UDP, as it has to perform the three-way handshake and ensure data is transmitted without errors.

TCP includes features such as congestion control, flow control, and error correction, which make it suitable for reliable transmission of data over the internet. It is the most commonly used protocol for internet communication and is used by all major web applications.

What are the differences between QUIC, UDP, and TCP?

1. Connection-oriented vs Connectionless

TCP is a connection-oriented protocol, which means it establishes and maintains a connection between the sender and receiver before data transmission. QUIC and UDP are connectionless protocols, which means they do not establish a connection before data transmission.

2. Reliability

TCP is a reliable protocol that ensures data is transmitted in the correct order and without errors. UDP is an unreliable protocol that does not guarantee the delivery of data, nor does it ensure it is transmitted in the correct order. QUIC is a protocol that combines the reliability of TCP with the speed of UDP.

3. Latency

UDP is a faster protocol than TCP, as it does not have to perform the three-way handshake. QUIC is designed to reduce the latency of internet communication even further by reducing the number of round trips required to establish a connection.

4. Features

TCP includes features such as congestion control, flow control, and error correction, which make it suitable for reliable transmission of data over the internet. QUIC includes features such as stream multiplexing, congestion control, and encryption, which makes it ideal for modern web applications. UDP is a simple protocol that is ideal for low-latency applications.

5. Adoption

TCP is the most commonly used protocol for internet communication and is used by all major web applications. UDP is mainly used for low-latency applications such as online gaming, video streaming, and VoIP. QUIC is a relatively new protocol but is now supported by all major web browsers, including Chrome, Firefox, and Safari.

In summary, TCP is a reliable protocol that guarantees the delivery of data and ensures it is transmitted in the correct order. UDP is a faster protocol that does not guarantee the delivery of data nor its correct order but is ideal for low-latency applications. QUIC is a protocol that combines the reliability of TCP with the speed of UDP, making it ideal for modern web applications.

Optimize your network with Tencent EdgeOne

EdgeOne supports both HTTP/3 and QUIC protocols, with the following versions of the QUIC protocol supported:

- If your users need to access through an App, the App needs to integrate support for HTTP/3 or QUIC protocols. EdgeOne provides a QUIC SDK to help you quickly complete the integration. For details, please refer to the QUIC SDK download and integration example.

- If your site is mainly a website, and the user's current browser supports the QUIC protocol and has enabled QUIC protocol access, your site only needs to enable HTTP/3 (QUIC) on EdgeOne to support it. You can check whether the current browser supports HTTP/3 by viewing if the browser supports HTTP/3.

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FAQ

1. What is HTTP/3?

HTTP/3 is the latest version of the Hypertext Transfer Protocol (HTTP), which is the foundation of any data exchange on the Internet. HTTP/3 is the next-generation transport protocol on the Internet, aiming to provide faster, more secure, and more reliable network communication. It is based on the QUIC (Quick UDP Internet Connections) protocol, which brings numerous innovations and advantages. 

2. What is the difference between QUIC and HTTP/3?

QUIC is a transport protocol that handles the reliable and ordered delivery of data packets between two endpoints. It provides features such as congestion control, flow control, and error correction to ensure a smooth and efficient connection. HTTP/3, on the other hand, is an application-layer protocol that defines how web browsers and servers communicate and exchange data. It builds on top of QUIC to provide features such as multiplexing, server push, and stream prioritization that can improve the performance of web applications.

3. What is HTTP/2?

HTTP/2 (originally named HTTP 2.0) is the second version of the Hypertext Transfer Protocol, used for the World Wide Web. It is primarily based on the SPDY protocol, implementing measures such as data compression of HTTP header fields, multiplexing of data transmission, and server push to reduce network latency and enhance client page load speed. HTTP/2 does not change the application semantics of HTTP, still utilizing HTTP request methods, status codes, and header fields. It primarily modifies the message transmission format of HTTP, enhancing performance through the introduction of binary framing.

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