How to accelerate access to a specific IP - Global Accelerator

Use case

A company headquartered in US (Silicon Valley) deploys an enterprise application on a self-managed server. Employees at the China (Hong Kong) office experience high latency, jitter, and packet loss when accessing the application over the unstable public network.

You can configure Global Accelerator so that traffic from the Hong Kong (China) office enters the Alibaba Cloud acceleration network at a nearby access point and reaches the US server through intelligent routing, reducing latency for Hong Kong (China) users.

Note

This example uses a pay-as-you-go standard Global Accelerator instance to configure the Global Accelerator service to accelerate access to a backend service at a specific IP address. Before you purchase a pay-as-you-go standard Global Accelerator instance, note the following:

Pay-as-you-go GA instances use Pay-By-Data-Transfer for bandwidth billing. You do not need to associate a bandwidth package. Cloud Data Transfer (CDT) handles traffic billing.
The first time you use a pay-as-you-go GA instance, you must Activate the Service.

Step 1: Configure basic information about an instance

Log on to the GA console.
On the Instances page, click Create Standard Pay-as-you-go Instance.

In the Basic Instance Configuration step, configure the parameters based on the following table and click Next.

Parameter	Description
GA Instance Name	Enter a name for the GA instance.
Instance Billing Method	Pay-As-You-Go is selected by default. You are charged instance fees, Capacity Unit (CU) fees, and data transfer fees for pay-as-you-go standard Global Accelerator instances. For more information about instance fees and CU fees, see Billing for pay-as-you-go Global Accelerator instances. For more information about data transfer fees, see Data transfer billing.
Resource Group	Select the resource group to which the standard Global Accelerator instance belongs. The resource group must be created by the current Alibaba Cloud account in Resource Management. For more information, see Create a resource group.

Step 2: Configure an acceleration area

Configure an Global Accelerator for the Global Accelerator instance to specify user regions and allocate acceleration bandwidth.

On the Configure acceleration areas page, configure the following parameters and click Next.

Parameter	Description
Acceleration Area	Select one or more regions to accelerate and click Add to List. In this example, the China (Hong Kong) region in the Asia Pacific area is selected.
Assign Bandwidth
Maximum Bandwidth	Set the bandwidth for the acceleration region. Valid range: 2 to 10,000 Mbps per region. The maximum bandwidth serves as a speed limit. Data transfer fees are billed by CDT. In this example, the default value of 200 Mbps is used. Important If the maximum bandwidth is too low, traffic may be dropped due to speed limiting. Plan the maximum bandwidth based on your business requirements.
IP Protocol	Select the IP protocol used to access the Global Accelerator service. In this example, the default value IPv4 is used.
ISP Line Type	Select the ISP line type used to access the Global Accelerator service. In this example, BGP (Multi-ISP) is selected.

Step 3: Configure a listener

A listener listens for connection requests and distributes the requests to endpoints based on the port and the protocol that you specify. 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, network traffic is distributed to the optimal endpoint in the endpoint group.

On the Configure Listeners page, configure the following parameters and click Next.

Parameter	Description
Listener Name	Enter a name for the listener.
Routing Type	Select a routing type. In this example, Intelligent Routing is selected.
Protocol	Select a protocol for the listener. In this example, TCP is selected.
Port	Specify the listener port for receiving and forwarding requests. Valid values: 1 to 65499. In this example, port 80 is used.
Client Affinity	Enable client affinity to direct all requests from the same client to the same endpoint for stateful applications. In this example, Source IP Address is selected.

Step 4: Configure an endpoint group and endpoints

On the Configure an Endpoint Group page, configure the endpoint group and endpoints based on the following information, and then click Next.

Parameter	Description
Region	Select the region where the endpoint group is deployed. In this example, US (Silicon Valley) is selected.
Endpoint Configuration	Configure the destination servers (endpoints) that process client requests: Backend Service Type: Select Custom Public IP. Backend Service: Enter the IP address of the backend service that you want to accelerate. Weight: Enter a weight for the endpoint. Valid values: 0 to 255. Global Accelerator routes traffic to endpoints based on the weights that you configure. In this example, the default value of 255 is used. Warning If the weight of an endpoint is set to 0, Global Accelerator stops distributing traffic to that endpoint. Proceed with caution.
Preserve Client IP	Select whether to preserve client IP addresses. When enabled, backend servers can retrieve client source IP addresses. For TCP listener configurations, configure backend servers to retrieve client IPs. The method varies by backend service type. Preserve client IP addresses. In this example, this feature is disabled.
Traffic Distribution Ratio	Configure the traffic ratio for different endpoint groups. Valid values: 0 to 100. In this example, the default value of 100% is used.
Health Check	Enable or disable health checks. When enabled, health checks monitor endpoint availability. Enable and manage health checks. In this example, this feature is disabled by default.

On the Configuration Review page, review the settings and click Submit.

Note
Creating a GA instance takes about 3 to 5 minutes.
Optional: After the task is complete, click Go to Instance Details. On the instance details page, you can view the instance configurations on tabs such as Instance Information, Listeners, and Acceleration Areas.

Step 5: Test the acceleration performance

Note

If you specify UDP as the protocol when you add a listener to Global Accelerator, you can verify the acceleration performance of Global Accelerator by using UDPing. For more information, see Verify the acceleration performance of a UDP listener.

Open the command-line window on a computer in the acceleration area. In this example, the computer is in the China (Hong Kong) region.
Run the following command to check data packet latency.
```
curl -o /dev/null -s -w "time_connect: %{time_connect}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n" "http[s]://<accelerated IP>[:<port>]"
```
Take note of the following parameters:
- time_connect: The period of time that is required 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 period of time from the time when the client sends a request to the time when the client receives the last byte from the backend server. Unit: seconds.
The test results show that using Global Accelerator reduces the total connection time from clients in China (Hong Kong) to the backend service in the US (Silicon Valley) region. This indicates that the latency for clients to access the backend service is lower.

Figure 1. Access latency before acceleration (testing the backend service IP address)

Figure 2. Access latency after acceleration (testing the accelerated IP address)
Note
The actual acceleration performance of the Global Accelerator service depends on your specific tests.

(Optional) Step 6: Configure a CNAME record

If you have a domain name for your enterprise application, such as example.com, configure the following:

Add a CNAME record to map the domain name www.example.com to the CNAME that is assigned to the Global Accelerator instance.
Add an A record to map the domain name www.example.com to the IP address of the backend service in the US (Silicon Valley) region, and set the query source to North America_United States.

Note

Alibaba Cloud DNS Free Edition does not support region-based intelligent resolution. Upgrade to Enterprise Ultimate or Premium Edition. Renewal. If you use a different DNS provider, follow their instructions.

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

Note
If your domain name is not registered with Alibaba Cloud, add it to the Alibaba Cloud DNS console first. Add a domain name. If already registered, skip this step.

On the Settings page, click Add Record. Add a CNAME record and an A record based on the following information and click OK.

Parameter	Description
Record Type	Select CNAME.	Select A.
Hostname	Enter a prefix for your domain name. In this example, enter `www`.
DNS Request Source	Keep the default value.	Select Region, Outside Chinese Mainland, North America, and United States in sequence.
TTL	Cache time for the DNS record. Smaller values propagate changes faster across regions. In this example, the default value of 10 minutes is used.
Value	Enter the CNAME assigned to the Global Accelerator instance. On the Instances page, you can view the CNAME assigned to the Global Accelerator instance.	Enter the IP address of the backend service in the US (Silicon Valley) region.

After configuration, employees access the enterprise application through the domain name www.example.com. US employees connect directly to the backend service in US (Silicon Valley). Employees in China (Hong Kong) and other regions are routed through Global Accelerator.

More information

You can also use a quick configuration template for Global Accelerator provided by Resource Orchestration Service (ROS) to accelerate access from China (Hong Kong) to the backend service in the US (Silicon Valley) region over an IP address. To do this, go to the quick configuration template and follow the on-screen instructions to configure and try out Global Accelerator.