This guide introduces basic CDN concepts to help you understand and use Atomile CDN products more effectively.

Origin Server

The origin server is your primary website server where your business content and services are hosted. It serves as the source of content for acceleration and distribution. When a CDN edge server does not have the requested content in its cache, it retrieves the content from the origin server and then responds to the user. The origin server can be either Atomile Object Storage or your own origin server, identified by an IP address or a domain name.

CDN PoP

A CDN PoP (Point of Presence), also known as an edge server, caches content from the customer’s origin server to respond quickly to end-user requests.

Acceleration Domain

An acceleration domain is a domain configured for CDN services through which end users access your services and benefit from faster content delivery. For example, after adding example.com to a Content Acceleration or Dynamic Content Acceleration service, that domain becomes an acceleration domain. In this documentation, an acceleration domain may sometimes be referred to simply as a domain.

CNAME Record / CNAME Domain

A CNAME record, or Canonical Name record, is a type of DNS record that maps an alias domain name to a canonical domain name. In CDN services, it is typically used to associate your custom domain with a CDN-provided domain, which ultimately resolves to the IP addresses of CDN edge servers.

In the context of Atomile, when you add an acceleration domain in the Atomile console, the system assigns a domain name that serves as the CNAME domain. You must then configure a CNAME record with your DNS service provider. This record directs requests for your custom domain, such as example.com, to the assigned CNAME domain. DNS resolution then continues from the CDN domain to the actual CDN edge servers that cache and serve your content. This setup helps distribute traffic across the global CDN infrastructure and accelerates content delivery by serving requests from the nearest available edge server.

Static Content

Static content refers to content that returns the same data in response to multiple requests, such as images, videos, web files (HTML, CSS, and JavaScript), and software packages. By caching static content from the origin server on CDN nodes around the world, the CDN allows users to access nearby cached content, thereby improving access speed.

Dynamic Content

Dynamic content refers to content that may return different data in response to multiple requests, such as dynamic web pages (ASP, JSP, PHP, and others), API interfaces, and database interaction requests.

Back-to-Origin

When a CDN edge server does not have the requested content in cache, or when the cached content has expired, the server retrieves the content from the origin server and then responds to the user. This process is called Back-to-Origin.

Origin Host

Also known as the Host header, this required field in an HTTP request specifies the hostname or domain name of the server that the client wants to communicate with. It is important because multiple domains can share the same origin IP address on a single origin server, and the Host header identifies which domain the client is requesting.

Cache Prefetch

Cache prefetch is a proactive strategy that preloads large files or predicted popular content onto CDN edge servers in advance. This allows users to immediately access cached files when requested, without waiting for the content to be fetched from the origin server. As a result, it helps reduce bandwidth pressure on the origin server and improves file response speed.

Cache Purge

When cached file versions on CDN edge servers become outdated, the cache purge feature allows you to specify file URLs or directories to remove outdated cached content from edge servers. After the purge, when a CDN edge server receives a user request for that content, it retrieves the latest version from the origin server.