This topic describes how to use Global Accelerator (GA) to accelerate connections to backend servers that have specific IP addresses.

Scenario

The following scenario is used as an example in this topic. A company has built two on-premises backend servers Server 1 and Server 2 in the US (Silicon Valley) region and deployed enterprise applications on the servers. Server 1 processes up to 20% of the total workloads. Server 2 processes up to 80% of the total workloads. Unstable network performance may cause issues such as increased latency, network jitter, and packet loss. These issues arise when users from the office in the China (Hong Kong) region connect to the enterprise applications deployed in the US (Silicon Valley) region over the Internet. Accelerate transmission of network traffic destined for a specified IP address

To accelerate connections to the backend servers, you can create a GA instance that provides an access point in China (Hong Kong). When users in the China (Hong Kong) region send requests to the servers, the access point in the China (Hong Kong) region receives the requests and forwards the requests to the endpoints in the US (Silicon Valley) region through intelligent routing. The system uses the endpoints to distribute 20% of the requests to Server 1 and 80% of the requests to Server 2.

Procedure

Procedure

Step 1: Purchase a GA service bundle

You can enter the information about the web service in the GA console. After you enter the information, the system generates a list of recommended services. The list includes a GA instance and a basic bandwidth plan.

  1. Log on to the Global Accelerator console.
  2. In the upper-right corner of the Instances page, click Purchase Guide.
    Note If this is the first time that you use the GA service, skip this step.
    Purchase Guide
  3. In the Enter the required information to generate a list of recommended services section, enter the required information and click Generate Service List.
    Parameter Description
    Acceleration Area Select the region that requires acceleration.

    In this example, China (Hong Kong) is selected.

    Service Region Select the region where the backend servers are deployed.

    In this example, US (Silicon Valley) is selected.

    ICP Filing Specify whether you have applied for an Internet Content Provider (ICP) number for the domain name of the web service.

    In this example, No is selected.

    Note All websites must obtain an ICP number before they are allowed to provide services to users in mainland China. For more information, see What is an ICP filing?.
    Server Area Specify whether the web service is deployed on Alibaba Cloud.

    In this example, Off Alibaba Cloud is selected.

    Peak Bandwidth Range Enter the bandwidth required during peak hours. Unit: Mbit/s.

    In this example, 2 is entered.

    Maximum Concurrent Connections The maximum number of concurrent connections that a GA instance supports. When the number of existing concurrent connections reaches the upper limit, new connection requests are dropped.

    In this example, 5 Thousand is selected.

  4. In the Recommended Service List section, click Generate Service List after you confirm the information.
    Generate Service List
  5. On the buy page, set the following parameters and click Buy Now to complete the payment.
    Parameter Description
    Term Select the subscription duration.
    Specification Select a specification for the GA instance.

    In this example, Small I (Specification Unit) is selected.

    Bandwidth Type Select a bandwidth type for the basic bandwidth plan.

    In this example, Premium is selected.

    Peak Bandwidth Select the bandwidth limit of the basic bandwidth plan.

    In this example, 2 Mbit/s is selected.

Step 2: Add an acceleration area

After you purchase a GA instance, you can add an acceleration area, specify the region where users are located, and then allocate bandwidth resources to the region.

  1. On the Instances page, find the GA instance and click its ID.
  2. Click the Acceleration Areas tab and then click Add Region on the Asia Pacific tab.
  3. In the Add Acceleration Area dialog box, set the following parameters and click OK.
    Parameter Description
    Regions Select the region where the users are located.

    In this example, China (Hong Kong) is selected.

    Bandwidth Specify a bandwidth value for the acceleration region.

    In this example, 2 Mbit/s is entered.

    Internet Protocol Select the IP address version used to access GA.

    In this example, IPv4 is selected.

    After you add the region, the system assigns an accelerated IP address to the region that is added to the GA instance. This accelerated IP address is used to accelerate data transfer from users in the specified region to the specified backend servers through GA. Accelerated IP address

Step 3: Add a listener and an endpoint group

A listener checks for connection requests and then distributes the requests to backend servers based on the specified protocol and ports. Each listener is associated with an endpoint group. You can associate an endpoint group with a listener by specifying the region to which you want to distribute network traffic. After you associate an endpoint group with a listener, traffic is distributed to the optimal endpoint in the associated endpoint group.

  1. On the instance details page, click the Listeners tab and then click Add Listener.
  2. On the Configure Listener & Protocol wizard page, set the following parameters and click Next.
    Listener
    Parameter Description
    Listener Name Enter a name for the listener.

    The name must be 2 to 128 characters in length, and can contain letters, digits, underscores (_), and hyphens (-). The name must start with a letter.

    Protocol Select the protocol of the listener.

    In this example, TCP is selected.

    Port Number Specify a listener port. The port is used to receive and forward requests to endpoints. Valid values: 1 to 65499.

    In this example, the value is set to 80.

    Client Affinity Specify whether to enable client affinity. If client affinity is enabled, requests from the same client are forwarded to the same endpoint when the client connects to a stateful application.

    In this example, Source IP Address is selected.

  3. On the Configure Endpoint Group wizard page, set the following parameters and click Next.
    IP address endpoint
    Parameter Description
    Endpoint Group Name Enter a name for the endpoint group.

    The name must be 2 to 128 characters in length, and can contain digits, underscores (_), and hyphens (-). The name must start with a letter.

    Region Select the region to which the endpoint group belongs, which is the region to which the destination servers belong.

    In this example, US (Silicon Valley) is selected.

    Backend Service Specify whether the backend service is deployed on Alibaba Cloud.

    Off Alibaba Cloud is selected in this example.

    Preserve Client IP Specify whether to preserve client IP addresses. After the feature is enabled, backend servers can obtain source IP addresses of clients.

    In this example, this feature is disabled.

    Endpoint An endpoint serves as the destination that a client requests to access. Set the following parameters to configure an endpoint:
    1. To configure Server 1 as an endpoint, set the following parameters:
      • Backend Service Type: Select Custom IP Address from the drop-down list.
      • Backend Service: Enter the IP address that you want to accelerate. In this example, the IP address of Server 1 is specified.
      • Weight: Specify a weight for the endpoint. Valid values: 0 to 255. GA routes network traffic to endpoints based on the specified weights. In this example, the weight of Server 1 is set to 10.
    2. Click Add Endpoint to configure Server 2 as an endpoint. Set the following parameters:
      • Backend Service Type: Select Custom IP Address from the drop-down list.
      • Backend Service: Enter the IP address of Server 2.
      • Weight: Set the weight of Server 2 to 40.
    Notice If you set the weight of an endpoint to 0, GA does not route network traffic to the endpoint. Proceed with caution.
  4. On the Confirm wizard page, confirm the configurations of the listener and endpoint, and then click Submit.

Step 4: Test the acceleration performance

Note If you specify UDP as the protocol when you add a listener, you can verify the acceleration performance by using UDPing. For more information, see Test the acceleration performance a GA instance that uses a UDP listener.
  1. Open the CLI on an on-premises machine in the China (Hong Kong) region.
  2. Run the following command to query the network latency:
    curl -o /dev/null -s -w "time_connect: %{time_connect}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n" "http[s]://<accelerated IP address>[:<port>]"
    In the command:
    • time_connect: the period of time that it takes to establish a TCP connection. Unit: seconds.
    • time_starttransfer: the start time of data transfer. The start time refers to the amount of time from when the client sends a request to the backend server to when the first byte is sent to the client. Unit: seconds.
    • time_total: the total connection time. The total connection time refers to the amount of time from when the client sends a request to when the client receives the last byte from the backend server. Unit: seconds.