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Infrastructure

CDN (Content Delivery Network)

A distributed network of servers that caches and delivers web content from locations geographically close to users, reducing latency and improving download speeds for websites and streaming.

What It Means

A Content Delivery Network (CDN) is a geographically distributed network of caching servers that store and deliver internet content from locations close to end users, reducing latency and offloading traffic from origin servers. The largest commercial CDNs include Cloudflare (serves roughly 20% of global web traffic), Akamai Technologies (the pioneer of the category, founded 1998, serves an estimated 15 to 30% of global traffic), Amazon CloudFront (AWS), Fastly, Google Cloud CDN, and Microsoft Azure CDN. Video-specific CDNs include Netflix Open Connect and Google Global Cache. Together, CDNs deliver an estimated 60 to 70% of all internet traffic. When you watch Netflix, the video almost certainly comes from a Netflix Open Connect Appliance (OCA) embedded directly inside your ISP's network, reducing the round-trip from hundreds of milliseconds (fetching from Netflix's origin data center in California or Virginia) to single-digit milliseconds (fetching from a local OCA cache in your ISP's regional headend). CDNs fundamentally changed the economics of streaming: without CDN caching, Netflix would consume far more peering and transit bandwidth than available ISP interconnect capacity. Speed test results can vary depending on which CDN server you connect to, this is why Ookla, Fast.com, M-Lab NDT, and the FCC speed test can show materially different numbers on the same connection. For the Broadband Grade speed test, the tool selects a geographically close CDN endpoint to measure delivered throughput in a manner representative of real-world streaming and web browsing.

Frequently Asked Questions

What does "CDN" mean?

A distributed network of servers that caches and delivers web content from locations geographically close to users, reducing latency and improving download speeds for websites and streaming.

Why does CDN matter for internet quality?

A Content Delivery Network (CDN) is a geographically distributed network of caching servers that store and deliver internet content from locations close to end users, reducing latency and offloading traffic from origin servers. The largest commercial CDNs include Cloudflare (serves roughly 20% of gl...

Related Terms

ISP (Internet Service Provider)
A company that provides internet access to consumers and businesses. Major U.S. ISPs include Comcast (Xfinity), Charter (Spectrum), AT&T, Verizon, and T-Mobile.
Last Mile
The final leg of the network connecting the ISP's infrastructure to the customer's home or business. The last mile is typically the most expensive part of broadband deployment.
Provider Competition
The number of ISPs offering broadband service in a given area. Areas with three or more competitors typically have lower prices and faster speeds than monopoly or duopoly markets.
Municipal Broadband
Internet service owned and operated by a local government or public utility, rather than a private ISP. Often provides faster speeds at lower prices than incumbent providers.

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About This Data

Definitions based on FCC standards, industry specifications, and federal broadband policy. Speed benchmarks reflect 2024 FCC standards. See our methodology.

this entity is one of the U.S. internet availability and broadband speed concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the the FCC Broadband Data Collection (BDC) data behind every per-entity page on the site.

In the the FCC Broadband Data Collection (BDC) data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.

Source: FCC Broadband Data Collection, 2026.