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What is a CDN edge server?

An edge server in a CDN is a component that resides at the "edge" or "periphery" of a network system and serves as a connection point between two or more distinct networks.

The main purpose of a CDN edge server, similar to a CDN in general, is to store content as close as possible to the requesting client machine, thereby reducing latency and improving page load speed.

An edge server is a type of "edge" device used to provide an entry point for a specific network system. Other common edge devices include routers and switches. These edge devices are often placed within Internet Exchange Points (IXPs) to allow different networks to interconnect and share data.

How does an edge server work?

In any given network layout, different devices connect together through predefined network patterns.

If a network wants to connect with another network or a larger Internet network, it needs some form of bridge to transmit access traffic from one location to another. The hardware devices that create this bridge at the edges of a network are called edge devices.

Networks connecting through the edges

In a typical home or office network with multiple interconnected devices, devices such as mobile phones or computers connect and communicate with the network using a hub-and-spoke model (all devices present in the same local area network [LAN], where a central hub acts as a gathering point for branch devices, and these branch devices communicate with each other through the central hub).

To connect a second network system to the first network system, there needs to be a connection made at certain points between these networks. The device through which networks can connect to each other is called an "edge" device.

Now, if a computer within Network A needs to connect to a computer within Network B, the connection must pass through the network edge and then enter the second network.

This model also works similarly in more complex contexts, such as when connections are made over the Internet. The data sharing capability of networks can also become congested depending on the capacity of the edge devices used for connectivity.

When connecting through the Internet, there are often multiple intermediate steps that need to be taken between Network A and Network B. To simplify, imagine each network as a circle, and the points where the circles touch each other are the network edges. To establish smooth connections over the Internet, networks come into contact with each other, and the data stream moves through various network edge nodes.

In general, the farther the connection, the more networks it has to traverse. A connection may go through multiple Internet service providers and the core infrastructure of the Internet before reaching its destination.

A CDN service provider will place servers in multiple locations, but the most important points are the connection points at the edges of networks (edge servers). These edge servers connect multiple networks together and enable fast and efficient access flow between networks.

Without a CDN, access flow may be slow or routed through complex paths from source to destination. In the worst-case scenario, the access flow may experience the "trombone effect" (data takes a complex route with significant distance despite the destination being geographically close) when connecting to a device along its path, causing the access flow to loop through a large geographical area and bounce back.

By placing edge servers at key locations, CDNs can provide content quickly to users across different networks. To learn more about the advancements in using CDNs, explore how CDN works here:

• Why should businesses use CDN for their websites?

What is the difference between an edge server and the original cloud server

The original cloud server is the web server that receives all the Internet traffic when the website does not use a CDN. Using the original cloud server without a CDN means that each Internet request has to go back to the actual location of that original cloud server, regardless of where the request originates in the world. This results in increased loading times and additional resource usage on the cloud server to serve the requesting clients.

CDN edge servers store and cache content at strategic locations to reduce the load on one or multiple original cloud servers. By moving static content such as images, HTML files, JavaScript, and other cacheable resources closer to the requesting clients, the caching performed by the edge servers can significantly reduce the time required to load resources from a website.

The original cloud server still plays a crucial role when using a CDN. For example, important server-side codes like database information for client authentication are typically maintained on the original server rather than the CDN edge servers.