What is the Average Latency of a CDN?

CDN Latency

June 10, 2024

For a well-optimized CDN, the average latency is typically in the range of 20 to 50 milliseconds. However, in some cases, it can be lower, especially if the user is near a major data center, or higher if there are network congestion or routing issues.

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Major CDN providers like Cloudflare, Akamai, and AWS CloudFront often report latencies on the lower end of this spectrum.

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How to Check CDN Latency?

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To check the latency of a CDN, you can use several methods and tools:

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Ping Command: You can ping the CDN server to measure the round-trip time (RTT) for packets to travel from your computer to the CDN server and back.some text
- Open a terminal or command prompt.
- Use the command ping [CDN server address].
- Observe the average time reported in milliseconds.
Traceroute Command: This helps to trace the path packets take to reach the CDN server and measure the latency at each hop.some text
- Open a terminal or command prompt.
- Use the command traceroute [CDN server address] (or tracert [CDN server address] on Windows).
- Review the latency at each hop along the path to the CDN server.
Web Performance Tools: Various online tools can help you measure CDN latency.some text
- Pingdom: Offers website monitoring and performance testing, including latency measurements and TTFB.
- GTmetrix: Provides detailed performance reports, including CDN latency.
- WebPageTest: Allows you to test website performance from different locations and provides insights into CDN latency.
Browser Developer Tools: Most modern browsers have built-in developer tools that can help measure latency.some text
- Open the developer tools (usually with F12 or right-click and select "Inspect").
- Go to the "Network" tab.
- Reload the page and observe the "Timing" details for various resources loaded from the CDN.
Third-Party Monitoring Services: Services like New Relic, Dynatrace, or Datadog can provide detailed monitoring and reporting on CDN performance metrics, including CDN latency, website latency, and average latency speed.

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Factors Affecting CDN Latency

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Several factors affect average latency speed, including:

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Factor	Sub-Factor(s)	Latency Range (ms)	Description
Geographical Distance	Same City	5 to 20	When the CDN server is located within the same city as the user.
	Same Country	20 to 50	When the CDN server is located in a different city but within the same country.
	Different Continent	100 to 200	When the CDN server is located on a different continent, leading to higher latency.
Network Congestion	Low Congestion	10 to 30	Low network traffic allows for faster data transmission.
Network Congestion	High Congestion	50 to 100	High network traffic can slow down data transmission, increasing latency.
Routing Efficiency	Direct Routes	10 to 30	Data takes a direct path with fewer hops, reducing latency.
Routing Efficiency	Multiple Hops	30 to 100	Data takes a more complex path with multiple hops, increasing latency.
Server Performance	High Performance Server	5 to 20	Fast servers with high capacity can handle requests quickly, reducing latency.
Server Performance	Low Performance Server	50 to 100	Slower servers with limited capacity can delay request processing, increasing latency.
DNS Resolution Time	Fast Resolution	10 to 20	Efficient DNS resolution speeds up the initial connection.
DNS Resolution Time	Slow Resolution	50 to 100	Delays in DNS resolution can add to the overall latency.
Peering Arrangements	Good Peering	10 to 30	Favorable peering arrangements facilitate faster data transfer.
Peering Arrangements	Poor Peering	50 to 100	Unfavorable peering arrangements can slow down data transfer, increasing latency.
Content Caching	Cached Content	5 to 20	Content already cached on the CDN server is delivered quickly.
Content Caching	Non-Cached Content	50 to 200	Content that needs to be fetched from the origin server can significantly increase latency.