You can use Alibaba Cloud DNS to configure intelligent DNS resolution for your online website or application. This allows you to accelerate and optimize user access across carriers or geographical areas. For example, you can configure DNS records for the domain name dns-example.com based on the following table.
The preceding configuration achieves the following results:
If a China Unicom user requests the domain name, 192.0.x.x is returned.
If a China Mobile user requests the domain name, 192.1.x.x is returned.
If a user of any other carriers requests the domain name, 192.2.x.x is returned.
What happens if the server of China Unicom (192.0.x.x) becomes faulty?
China Unicom users fail to access your website or application by using the domain name.
Users of China Mobile and other carriers are not affected.
How do I route China Unicom users to the server of another carrier after the server of China Unicom becomes faulty?
You can route China Unicom users to the server of another carrier by using Global Traffic Manager in Alibaba Cloud DNS. Global Traffic Manager performs health checks to determine whether a server is faulty. If the server of China Unicom becomes faulty, the DNS server forwards domain name requests to a backup server to implement failover.
For more information about Global Traffic Manager, see What is GTM?.