A CDN edge server is a computer positioned at the edge of a network, designed to store and deliver content efficiently to reduce latency and improve page load times. It serves as a bridge between different networks and is a crucial component in Content Delivery Networks (CDNs). The primary function of an edge server is to cache content close to the requesting client machine.

In a network layout, edge devices, including edge servers, connect separate networks and facilitate the flow of traffic. Networks connect across the edge, and the ability for different networks to share transit relies on the availability of edge devices. CDN providers strategically place edge servers at key locations, especially at the edge between different networks, to enable quick and efficient content delivery.

The key difference between an edge server and an origin server lies in their roles within a CDN. An origin server is the central web server that handles all Internet traffic when a web property is not using a CDN. In contrast, edge servers in a CDN store and cache content in various locations, reducing the load on origin servers and improving the speed of content delivery by bringing it closer to the end-users. Origin servers remain essential for maintaining server-side code and critical data.