Global Accelerator:Enable HTTP/3 for GA to enhance application access

QUIC and HTTP/3

The QUIC protocol is a transport protocol based on UDP that provides faster and more secure internet connections. The primary goal of QUIC is to address the performance bottlenecks of TCP and TLS in modern network environments, especially in high-latency networks and with multiplexed connections.

Due to its performance advantages, QUIC is widely considered a key technology for future internet transport protocols and is the underlying transport layer for HTTP/3. As major browsers and web servers begin to support QUIC, it is gradually becoming a part of modern internet infrastructure.

Use cases for the HTTP/3 protocol

• Improved web browsing experience: For web browsing, HTTP/3 can reduce page load times, especially for complex web pages that load multiple resources. With capabilities like multiplexing provided by QUIC, users see web content faster.

• Real-time communication applications: Applications that are highly sensitive to latency, such as instant messaging, video conferencing, and online gaming, can benefit from HTTP/3. QUIC's low latency and fast error recovery mechanisms help ensure a smooth real-time communication experience.

• Applications on mobile devices: Connections on mobile networks are often unstable. HTTP/3 provides a more stable connection experience for mobile users through QUIC's connection migration feature and its ability to adapt to network changes.

• Streaming media services: For video and audio streaming services, such as short-form video and live streaming, HTTP/3 can ensure a smoother playback experience by reducing buffering and interruptions, thereby improving user satisfaction.

• High concurrency scenarios: For large e-commerce or social media platforms during peak traffic, the multiplexing capability of HTTP/3 can effectively handle a large number of concurrent requests without encountering the head-of-line blocking issues common with HTTP/2.

Supported protocol versions and client requirements

GA supports the h3 version of the HTTP/3 protocol. You must ensure that the client's supported HTTP/3 version is compatible with GA's version:

• The corresponding Chrome browser version is Chrome 87 or later. If you use other browsers, you need to ensure the browser supports HTTP/3.

• If you use other clients such as self-developed applications, the client must integrate network libraries that support the QUIC protocol, such as: lsquic-client, cronet network library, ngtcp2, and quiche.

How GA negotiates HTTP/3 with clients

Before establishing an HTTP/3 connection between the server and client, due to the connectionless nature of UDP, the client typically first establishes a secure connection with the server through a TLS 1.3 handshake, and automatically negotiates the use of HTTP/3 during this process, without requiring explicit specification by the user or developer.

HTTP/3 is a new protocol, not an update or extension of HTTP/1.1 or HTTP/2. It is based on the QUIC protocol. Due to this fundamental change, HTTP/3 is not directly compatible with previous HTTP versions. To ensure backward compatibility, web servers and browsers typically implement multiple HTTP versions, including HTTP/1.1, HTTP/2, and HTTP/3. They can automatically negotiate the most suitable protocol version based on what both the client and server support. This means that while HTTP/3 itself is not directly compatible with older HTTP versions, modern client and server implementations handle protocol selection and fallback automatically, so users and developers do not need to manage compatibility issues.

The following process describes how GA negotiates an HTTP/3 connection with a client:

1. After configuring the maximum HTTP version to HTTP/3 in the HTTPS listener of the GA instance, GA will announce HTTP/3 support to the client. This support is announced in the HTTP response header Alt-Svc, with the Alt-Svc header value: Alt-Svc : h3=":$quic_port"; ma=3600.

2. The client attempts to establish an HTTP connection with GA. Note:

   • When the client cannot establish an HTTP/3 connection, it always falls back to using HTTP/1.1 or HTTP/2.

   • The client supports caching cookies related to HTTP/3.

   • Scenarios where HTTP/3 connections cannot be established:

     • The HTTP/3 version supported by the client is incompatible with the HTTP/3 version supported by GA.

     • GA detects UDP traffic blocking or rate limiting that prevents HTTP/3 from working.

     • The client does not support HTTP/3 at all, so it does not attempt to negotiate an HTTP/3 connection.

3. Enabling or disabling HTTP/3 in GA does not affect existing connections or GA's ability to serve traffic over other HTTP versions.

Step 1: Configure a GA instance and enable HTTP/3

1. Log on to the GA console.

2. On the Instances page, click Create Standard Pay-as-you-go Instance

3. On the Basic Instance Configuration page, customize the GA instance name. After you complete the configuration, click Next.

4. On the Configure Acceleration Area page, select China (Beijing) for Acceleration Area. You can keep other parameters at their default values or modify them as needed. After you complete the configuration, click Next.

   Important

   If the bandwidth peak value is set too low, throttling may occur causing traffic to be dropped. Please plan the bandwidth peak value reasonably to ensure it matches your business requirements.

   

5. On the Configure listeners page, configure the following information. You can keep other parameters at their default values or modify them as needed. After you complete the configuration, click Next.

   Parameter	Description
   Protocol	Select HTTPS.
   Maximum HTTP Version	Select HTTP/3. Note If your pay-as-you-go GA instance does not support configuring Maximum HTTP Version, it may be because the instance version does not support it. To use this feature, please contact your account manager to request an instance upgrade. If the client does not support HTTP/3, Global Accelerator also supports HTTP/2 or HTTP/1.1 request access.
   Port	Select the HTTPS default port 443.
   Server Certificate	Select the SSL certificate corresponding to your domain name.

   

6. On the Configure an endpoint group page, configure the following information. Keep other parameters at their default values or modify them as needed. After you complete the configuration, click Next.

   Parameter	Description
   Region	Select Germany (Frankfurt).
   Endpoint Configuration	Select ECS for Backend Service Type. Select your application server for Backend Service.
   Port Mapping	When the listener port and application service port are different, you need to configure port mapping relationships. In this article, the listener port is configured as 443, and the endpoint port is configured as 80.
   Cross-border Acceleration Settings	In this scenario, when business configuration involves cross-border access acceleration between the Chinese mainland and regions outside the Chinese mainland, or between other countries and regions, you need to read and select Compliance Commitments Regarding Cross-border Data Transfers.

   

   

7. On the Configuration Review page, review the configuration and click Submit, then wait for the instance to complete creation and configuration.

Step 2: Configure DNS records

Point your domain name to the CNAME of the GA instance. This forwards access requests to GA for acceleration.

1. Log on to the GA console.

2. Select the GA instance for which you want to configure domain name resolution, and copy its corresponding CNAME address.

3. Complete the following steps to add a CNAME record.

   1. On the Public Zone page, find your target custom domain name, and click Settings in the Actions column.

      Note

      For domain names not registered with Alibaba Cloud, you need to first add the domain name to the Cloud DNS console before you can configure domain name resolution.

   2. On Settings page, click Add Record.

   3. In the Add Record panel, configure the following information to complete the CNAME record configuration, then click OK.

      Parameter	Description
      Record Type	Select CNAME from the drop-down list.
      Hostname	The prefix of your domain name.
      Query Source	Select Default.
      TTL	Time To Live, which indicates the cache time of DNS records on DNS servers. This article uses the default value.
      Record Value	Enter the CNAME address corresponding to the domain name, which is the CNAME address of the GA instance you copied.

Step 3: Verify HTTP/3 and acceleration effect

Use a client located in the China (Beijing) acceleration area to test the video acceleration effect.

1. Test the GA acceleration effect using HTTP/3:

   Open the developer tools in your browser and access https://<your custom domain name> to normally access the backend service. You can disable browser caching to avoid cache impact on HTTP/3 negotiation, for example, by checking Disable cache in Chrome.

   

2. Test the GA acceleration effect without using HTTP/3:

   Modify the HTTPS listener configuration parameters of the GA instance, changing Maximum HTTP Version to HTTP/2.

   Open the developer tools in your browser and access https://<your custom domain name> to normally access the backend service.

   

3. Test without GA acceleration:

   If the application server does not have a public IP address, bind an Elastic IP Address (EIP) to it.

   Open the developer tools in your browser and directly access http://<public IP address>:<port> to normally access the backend service.

   

4. Acceleration effect comparison:

   Summarizing the test data above, it can be seen that using GA acceleration with HTTP/3 improves the speed at which clients access videos on the backend server.

   Scenario	Page preload time (3.3MB)	Full video load time (112 MB)	Page preload comparison	Full video load comparison
   Scenario 1: Using GA with HTTP/3	16.86 seconds	3.8 minutes	Compared to Scenario 2: 0.78s faster (4.42% improvement)	Compared to Scenario 2: 0.4 min faster (9.52% improvement)
   Scenario 2: Using GA without HTTP/3	17.64 seconds	4.2 minutes	Compared to Scenario 3: 48.36s faster (73.27% improvement)	Compared to Scenario 3: 34.4 min faster (89.12% improvement)
   Scenario 3: Not using GA acceleration	1.1 minutes	38.6 minutes	/	/

   Note

   The examples and data in this article are for reference only. Actual acceleration effects will vary based on your specific tests.