The QUIC protocol provides enhanced security for data transmission between clients and CDN edge nodes and also accelerates content delivery. This topic introduces QUIC and the billing rules, and describes how to enable QUIC.

What is QUIC?

QUIC is an experimental transport layer network protocol that provides the same security capabilities as TLS/SSL and reduces connection and transmission latency. QUIC is developed based on UDP and has excellent performance when network connections are weak. When packet loss and network latency issues are severe, QUIC can still ensure service availability. QUIC can implement different congestion control algorithms at the application layer regardless of the operating system or kernel that is used. Compared with TCP, QUIC supports flexible changes based on service requirements. QUIC is a suitable alternative when TCP optimization encounters bottlenecks.

QUIC supported by Alibaba Cloud CDN is implemented at Layer 7.

QUIC types

Alibaba Cloud CDN supports IETF QUIC and Google QUIC (gQUIC). Supported versions of gQUIC are Q39, Q43, and Q46.
  • IETF QUIC is a standard Internet protocol.
  • IETF QUIC is compatible with gQUIC versions G39, Q43, and Q46. We recommend that you use IETF QUIC.

How it works

The following figure shows how QUIC works with Alibaba Cloud CDN. Diagram

Client requirements

QUIC has the following requirements for clients:
  • If you use Google Chrome, the Alibaba Cloud CDN already supports the standard protocol of HTTP/3. Google Chrome can directly send QUIC requests to Alibaba Cloud CDN.
  • If you use a self-developed app, the app must be integrated with a network protocol library such as lsquic-client, Cronet, ngtcp2, or quiche that supports QUIC.

Billing rules for QUIC

QUIC is a value-added service. You are charged based on the number of QUIC requests. For more information, see CDN pricing - QUIC.
  • Alibaba Cloud CDN identifies QUIC requests based on whether they are transmitted over UDP.
  • QUIC requests whose header specifies QUIC: Alibaba Cloud CDN identifies whether the request is a QUIC request. If so, you are charged for a QUIC request. If not, you are charged for an HTTPS request.

How to identify QUIC requests

In the following example, Google Chrome is used to show how to identify QUIC requests.

Procedure: Right-click a blank space on a web page and select Inspect > Network. If the Protocol column displays h3-29, it indicates that the request is a QUIC request.
Note If the Protocol column is not displayed, refresh the page, right-click, and then select Header Options > Protocol.

The following figure shows that the Protocol column displays h3-29, which indicates that the request is a QUIC request.