An edge server is any type of server that resides on the logical edge of two networks, typically between a private network and the internet.
It can serve many purposes depending on the context. The major purpose of the content delivery network is to store content at the closest location to the requesting client machine, thereby reducing the latency times and improving the page load times. An edge server provides a gateway for entering into the network. Edge devices are usually placed inside internet exchange points to allow different networks to connect and share transit.
How does an edge server work?
In any network, many devices connect to each other using one or more than one pre-defined network patterns. If any network wants to connect another network then it must have some sort of bridge and edge devices can be used to create that bridge. In a typical scenario, mobile or computer devices connect or disconnect through a hub-and-spoke network model.
All of these computing devices exist within a LAN and each network device is connected to a central router through which the devices are able to communicate with each other. In order to connect two networks, a connection has to be developed between two networks which are done via an edge server.
For example, a computer resides inside a network X and wants to connect to a computer residing inside the Network Y. For two computers to connect, the connection must pass from network X to the edge server and then the network Y. The same methodology becomes more complex when connections are being made across the internet. The ability for networks to share transit is bottlenecked by the availability of edge devices between them. When a connection must pass through the internet then more intermediary steps have to be taken between network X and network Y.