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    ENS:Configure a UDP listener

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    ENS:Configure a UDP listener

    Last Updated:Jun 11, 2024

    If your service prioritizes real-time content delivery over reliability, such as video chats and real-time financial market pushes, you can add a UDP listener to an Edge Load Balancer (ELB) instance to forward UDP requests to backend servers.

    Prerequisites

    An ELB instance is created. For more information, see Create an ELB instance.

    Procedure

    1. Log on to the ENS console.

    2. On the ELB Instance page, find the ELB instance that you want to manage and click Listener Configuration in the Actions column.

    3. On the Listener tab, click Add Listener.

    4. Configure the parameters. The following table describes the parameters.

      Parameter

      Description

      Listener Name

      Specify a name for the listener.

      ELB Protocol

      Select UDP.

      Listener Port

      Specify a listening port that is used by ELB to receive requests and forward the requests to backend servers. Valid values: 1 to 65535.

      Note

      You cannot specify port 250, port 4789, or port 4790 for UDP listeners. They are reserved by the system.

      Advanced Settings

      Note

      Click Modify to configure the advanced settings.

      Scheduling Algorithm

      • Weighted Round-Robin (WRR): Backend servers that have higher weights receive more requests than backend servers that have lower weights.

      • Weighted Least Connections (WLC): Requests are distributed based on the combination of the weights and active connections of backend servers. If multiple backend servers have the same weight, requests are forwarded to the backend server that has the least number of connections.

      • Round-Robin (RR): Requests are distributed to backend servers in sequence.

      • Consistent Hashing (CH)

        • Consistent hashing based on source IP addresses is used. Requests from the same source IP address are distributed to the same backend server.

        • Consistent hashing based on Quick UDP Internet Connections (QUIC) IDs is used. Requests that contain the same QUIC ID are distributed to the same backend server.

      • IQCH: Consistent hashing based on specific three bytes of the iQUIC CIDs from the second byte is used.

      Obtain Client IP Address

      Specify whether to retrieve the IP addresses of clients. Only Layer 4 listeners support this feature. By default, this feature is enabled.

    5. Click Next, and configure health checks. For more information, see Configure health checks.

    6. After you configure health checks, click Next. Confirm the settings and click Create.

    7. On the Listener tab, find the listener that you want to enable and click Enable in the Actions column.