tencent cloud


Configuring a QUIC Listener

Last updated:2022-07-28 16:17:31

    You can create a QUIC listener to a CLB instance to forward encrypted QUIC requests from the client. For QUIC listeners, the real server can directly get the real client IP.

    QUIC (Quick UDP Internet Connection) is a transport layer network protocol designed by Google, multiplexing concurrent data streams using UDP. Compared with the popular TCP+TLS+HTTP2 protocol, QUIC has the following advantages:

    • Reduce the time to establish a connection.
    • Improve congestion control.
    • Multiplex without head-of-line (HOL) blocking.
    • Connection migration.

    Use Cases

    A QUIC listener supports connection migration. When your network changes, such as frequent switches between 4G and Wi-Fi networks, it can smoothly migrate the connections without interruption. This is suitable for audio/video services, game services, etc.


    • The QUIC listener is in beta test. To try it out, please submit a ticket.
    • QUIC listener is supported only for CLB but not classic CLB.
    • QUIC listener is supported only for CLB instances in VPCs but not the classic network.
    • Only IPv4 and IPv6 NAT64 CLB instances support the QUIC listener.


    You need to create a CLB instance first.


    Step 1. Configure a listener

    1. Log in to the CLB console and click Instance Management on the left sidebar.
    2. Select a region in the top-left corner of the CLB instance list page and click Configure Listener in the Operation column on the right.
    3. Under TCP/UDP/TCP SSL/QUIC Listener, click Create and configure the QUIC listener in the Create Listener pop-up window.
      1. Basic Configuration
      Configuration Item Description Example
      Name Listener name. test-quic-443
      Listener Protocol and Ports
      • Listener protocol: QUIC is used in this example. After QUIC is selected, CLB can receive QUIC requests made by clients, but TCP is still used between CLB and real server.
      • Listener port: a port used to receive requests and forward them to the real server. Port range: 1-65535.
      • The listener port must be unique in the same CLB instance.
      SSL parsing method One-way authentication and mutual authentication are supported. One-way authentication
      Server certificate You can select an existing certificate in the SSL certificate console or upload a certificate. Existing certificate
      Balancing method For TCP SSL listeners, CLB supports two scheduling algorithms: weighted round robin (WRR) and weighted least connections (WLC).
      • WRR: Requests are sequentially delivered to different real servers according to their weights. Scheduling is done based on the number of new connections, where servers with higher weights will undergo more polls (i.e., a higher probability), while servers with the same weight process the same number of connections.
      • WLC: Loads of servers are estimated according to the number of active connections to the servers. Scheduling is done based on server loads and weights. If their weights are the same, servers with fewer active connections will undergo more polls (i.e., a higher probability).
      2. Health check
      For details of health check, see Configuring Health Check. 3. Session persistence
      QUIC listeners don't support session persistence currently.

    Step 2. Bind a backend CVM

    1. On the Listener Management page, click the created listener QUIC:443 to view the bound real servers on the right of the listener.
    2. Click Bind, select the target real server, and configure the server port and weight in the pop-up window.

      Default port: Enter the Default Port first and then select the CVM instance. The port of every CVM instance is the default port.

    Step 3. Configure a security group

    You need to configure a CLB security group to isolate public network traffic. For more information, see Configuring CLB Security Group.

    Step 4. Modify or delete a listener (optional)

    If you need to modify or delete a created listener, click the listener on the Listener Management page and click for modification or for deletion.


    Using QUIC Protocol on CLB

    Contact Us

    Contact our sales team or business advisors to help your business.

    Technical Support

    Open a ticket if you're looking for further assistance. Our Ticket is 7x24 avaliable.

    7x24 Phone Support