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Open CDN Debug on the hostname that delivers the content, from the network where the symptom appears. The page shows the Gcore edge server that handled the request and the client network for that request.

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Edge server for the request

The HTML page and JSON endpoint provide the same types of diagnostic information. Use the hostname configured for the CDN resource — the domain through which the content is delivered.
Replace cdn.example.com with the CDN hostname. The debug endpoint returns information about the corresponding CDN resource only when opened on that hostname. Read these objects in the JSON response: The HTML page also shows the request, client, and server details.
Request information for one CDN request
Client network and location for that request
Edge server name, address, and location
server_headers.server identifies the responding edge server. The server_headers object also contains its address and location. other_headers contains the headers captured with the request.
Request headers captured with this request

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Results from two networks

When users experience delays on one network but not another, check CDN Debug from both networks.
  1. Open the JSON URL from each network.
  2. Compare the client ASN, the edge server name, and the location.
  3. Run Speedtest from each network.
  4. Compare Ping and Download.
  5. If the edge server is the expected one and the file is still slow, check cache status and time to first byte in the video delivery guide.
Different edge servers indicate that the requests were handled by different CDN nodes, but do not necessarily indicate a routing issue. A higher Ping indicates greater latency to the diagnostic endpoint during that test. The following example uses illustrative values, not actual Gcore measurements. Network B has higher latency and lower download throughput in this test. These differences warrant further investigation but do not necessarily indicate a routing fault.

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Result interpretation

Use the following table to interpret common results and decide what to check next.

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Speedtest measurements

On the HTML page, open Speedtest and click Start test. Ping, Jitter, Download, and Upload come from /ping, /download, and /upload on the same CDN host.
Speedtest map with upload, download, ping, and jitter
Speedtest measures connectivity to the diagnostic endpoint. Its Ping, Jitter, Download, and Upload results do not necessarily reflect the performance of individual files delivered through the CDN. Attach the JSON body to a Gcore Support request when the comparison above is not enough. The body includes client and server addresses.