Tools Used

How It Works

The idea is simple: split traffic with DNS CNAME records. Domestic users go through the domestic CDN, overseas users go through the overseas CDN.

The rough flow:

1. User request: The user types vluv.space into the browser, and the OS sends a resolution request to the Local DNS Server (browsers and the OS also cache DNS results, skipped here)
2. Recursive query: If the Local DNS Server has no cache, it starts from the Root DNS Server, works its way down to the TLD (Top-Level-Domain) DNS Server for .space, and finally reaches the Authoritative DNS Server responsible for vluv.space
3. Different CNAME records by route: The Authoritative DNS Server, the endpoint of the whole query chain, holds all DNS records for vluv.space (e.g. A, CNAME, TXT records…); here that is Tencent Cloud’s DNSPod server.
   Tencent Cloud’s smart resolution detects where the user comes from and returns an IP accordingly, see DNS smart resolution route documentation - DNSPod
   • Domestic route: if the user is judged to be in mainland China, the authoritative DNS server returns a CNAME record pointing to the domestic CDN, e.g. vluv.space.s4cdn.dogecast.com.
   • Overseas visitors: otherwise, it returns a CNAME record pointing to the overseas CDN, e.g. vluv.space.eo.dnse4.com.

Final CDN resolution: After the Local DNS Server gets the CNAME record, it starts another full round of DNS resolution for the new domain in that record. In the end the CDN provider’s Authoritative DNS Server system takes over, and based on the user’s location, node load, and so on, returns the IP of the most suitable edge node. The user’s browser gets this IP, connects to the CDN edge node, and fetches the site content at full speed.

To verify the split routing works, run curl -I <your-domain> and inspect the response headers. Taking EdgeOne as an example, if the response contains an eo-cache-status header, the request went through an EdgeOne CDN node. See the EdgeOne default HTTP response headers documentation

Steps

Domestic and Overseas CDN Setup

Onboard each CDN following the provider’s instructions. For EdgeOne, see EdgeOne walkthrough: quick onboarding for security and acceleration - Tencent EdgeOne and just follow the steps. Roughly:

1. Add the site
2. Choose the service region and plan
3. Choose the acceleration region and access mode (usually CNAME access)

DNSPod CNAME Split Routing

DNSPod can return different CNAMEs depending on the user’s route, so domestic users go to Bitiful and overseas users go to EdgeOne.

Configuration steps:

1. Log in to the DNSPod console, select the domain, and open the “Record Management” page
2. Add two CNAME records, one for the domestic route and one for the overseas route, as in the table below

Do the same for the image hosting domain:

Results

Test site: ITDOG