What does CDN stand for?
CDN stands for Content Delivery Network. A geographically distributed set of servers that caches web content close to users to cut latency and offload the origin server. Many CDNs also absorb DDoS traffic and terminate TLS at the provider's edge.
A CDN is a network of servers spread around the world that deliver a website's content from a location close to each visitor. Copies of images, scripts, video and often whole pages are cached on these edge servers. A visitor's request is steered to a nearby edge, which answers from its cache and goes back to the site's own server, the origin, only for what it does not have. Pages load faster because the distance is shorter, the origin carries less load, and the capacity of the CDN helps to absorb traffic floods that would overwhelm a single site.
CDN in practice: an example
A news site hosted in Frankfurt has readers in Sydney, and for them every page is slow. After the site is put behind a CDN, the Sydney readers are served from an edge server in Australia that holds cached copies. Only the first request for a new article travels to Frankfurt. During a breaking story the origin sees a small part of the traffic, because the edges answer most of it.
What CDN is confused with
CDN vs load balancer: what is the difference?
A load balancer spreads requests across servers in one place. A CDN serves cached content from many places and chooses the one nearest the visitor. Large sites use both.
CDN vs DNS: what is the difference?
DNS turns names into addresses. CDNs often use DNS answers to steer each visitor to a nearby edge, but the CDN is the delivery network itself. What DNS stands for
Which exams cover CDN?
CDN is on the official CompTIA acronym list for one of the four exams covered here.
- Network+ N10-009: 1.0 (Networking Concepts).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A company's product videos load slowly for customers on other continents. The web server itself is not overloaded. Which solution addresses the cause?
- A content delivery network
- A larger DHCP scope
- A second domain controller
- Full-disk encryption on the server
Show the answer
A. A content delivery network. The delay comes from distance. A CDN serves the files from edge servers near the customers.
2. In a CDN, what is the origin?
- The site's own server, which holds the authoritative content
- The visitor's browser cache
- The nearest edge server
- The DNS root zone
Show the answer
A. The site's own server, which holds the authoritative content. Edges cache copies. The origin is where the content really lives and where an edge fetches anything it has not cached.
Sources: RFC 7336: Framework for Content Distribution Network Interconnection (CDNI); Microsoft Learn: What is Azure Front Door? (content delivery network); NIST glossary: CDN. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 12 November 2026.