Feature Overview

If you use multiple origin servers to host a domain name, you can group origin servers by region or ISP to balance workloads among the origin servers. Content Delivery Network (CDN) redirects requests from different client IP addresses to the closest origin servers or the origin servers that you specified for the requests transmitted over the networks provided specific ISPs. The following figure shows how ISP-based redirect works. CDN points of presence (POPs) redirect requests from China Telecom clients to the China Telecom origin server and requests from China Unicom clients the China Unicom origin server. The principle of region-based redirect is similar.

Application Scenarios

Scenario 1: Region-based redirect

A domain name is hosted on multiple origin servers which are distributed in Beijing, Shanghai, and Guangzhou respectively. After region-based redirect is configured, CDN redirects user requests from North China, Northwest China, and Northeast China to the origin server in Beijing, those from East China and Central China to the origin server in Shanghai, and those from South China and Southwest China to the origin server in Guangzhou. This ensures that user requests initiated in each region are responded to by the closest origin server. This also helps balance workloads among the origin servers.

Scenario 2: ISP-based redirect

A domain name is hosted on multiple origin servers. You can group the origin servers by China Telecom, China Unicom, and China Mobile. You can configure CDN to redirect requests from China Unicom clients, China Mobile clients, and China Telecom clients as well as other clients to specific origin servers respectively. This way, requests from China Telecom, China Unicom and China Mobile users are redirected to the corresponding origin servers, and requests from other network users are forwarded to the origin servers for China Telecom users. This improves the performance of handling cross-ISP back-to-origin requests.

Scenario 3: Multiple origin servers provide different content, and specific content is only visible to users in specific regions

For example, a domain name is host on an origin server deployed in China and an origin server deployed in a region outside China. The origin server in China hosts the Chinese edition of the website and the origin server deployed outside China hosts the English edition of the website. You can configure CDN to redirect requests from China to the origin server deployed in China and requests from regions outside China to the origin server deployed outside China.

Scenario 4: Region and ISP-based redirect

For example, a domain name is hosted on the following origin servers: Origin Server 1, Origin Server 2, and Origin Server 3. You can configure Origin Server 1 for Fujian Telecom, Guangxi Telecom, and Guangdong Telecom, Origin Server 2 for Shanghai Mobile, Zhejiang Mobile, and Jiangsu Mobile, and Origin Server 3 for other regions and ISPs.

Additional Considerations

You can configure region-based redirect at the city, province, and region/country levels. The priorities are as follows: City > Province > Region/Country. For example, if you configure Origin Server 1 for Suzhou City and Origin Server 2 for Jiangsu Province, CDN redirects requests from Suzhou City to Origin Server 1 and requests from other cities other than Suzhou City in Jiangsu Province to Origin Server 2.
Region- and ISP-based redirect can be used together with Origin request based on IPv4/IPv6. For example, you can configure CDN to redirect requests sent over IPv4 from users in Region A to Origin Server A and those sent over IPv6 from users in Region B to Origin Server B.

Procedure

Currently, this feature cannot be configured on your own. If you need to configure this feature, please contact our customer support team via hotline (852)31000000 or email global.noc@chinatelecomglobal.com. This feature can only be manually configured by the technical support team.

Please provide the following information:

• Describe the association relationships between ISPs/regions and origin servers. If you have multiple origin servers in the same region for the same ISP, specify the active and standby origin servers and the weights of the origin servers.

• Specify origin servers for handling requests from users that are not in the designated regions or that use network services not provided by the specified ISPs.

Content Delivery Network

Origin request based on region/ISP