For more information, see CDN.
As part of the Internet service, Domain Name System (DNS) is a distributed database that maps between domain names and IP addresses, making it easier for users to access the Internet. DNS uses TCP and UDP port 53. Each level of domain name is up to 63 characters, and a full domain name cannot exceed 253 characters.
Content Delivery Network (CDN) is a new layer of network architecture built on the existing internet. It consists of servers distributed across regions to accelerate internet content delivery. These high-performance cache nodes store your content based on caching policies. When a user makes a content request, it will be routed to the node closest to the user, reducing access latency and improving availability.