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Edge caching is the practice of moving memory storage, or caches, closer to the network’s edge, rather than housing it all at a central location. 

When end users access data in these edge caches, they are able to retrieve it much more efficiently than when it has to cross the entire network. This added efficiency ultimately reduces overall network loads and latency, and puts less stress on the data center.

This is where edge caching comes in. By caching a digital resource, temporary data, or files on an edge server, when a user requests that resource, it is served directly from the cache instead of processing the request on the edge or a distant server. 

To understand edge caching, it’s essential to understand the global digital world and the technology that makes it work. This article will explain the principles of edge servers and edge computing, how edge caching works, its benefits and drawbacks, and finally provide some examples of where edge caching is found on today’s networks.

What Is Edge Computing?

Edge computing is a distributed network framework where data and application service providers shift server processing as close to end users as possible. 

High-capacity remote data centers have long been vital to the digital ecosystem, but the distance between those data centers and users accessing them can create network disruptions, bandwidth limitations, and latency issues—especially in the era of Big Data and Content Delivery Networks (CDNs).

Edge computing solves this problem by creating edge data centers closer to the user, reducing latency and increasing performance and security.  

Though edge computing is a decades-old network concept aligned to remote computing, only in the new millennium has its value been realized. The proliferation of mobile and internet of things (IoT) devices and their capabilities has only been possible thanks to more storage and processing resources on the network edge. 

As a commercial industry, edge computing vendors offer solutions for building distributed networks that enable localized computing power and enrich connectivity with end users.

What Are Edge Servers?

An edge server is a physical hardware device strategically located at a network’s edge. It is typically a small, rack-mounted server equipped with high-performance computing resources, such as a powerful CPU and GPU. However, it can also be deployed on other smaller devices. 

Edge servers are designed to handle the processing and storage of data generated at the network’s edge, such as from IoT devices, cameras, and sensors. To bring the data closer to the user, edge servers are typically deployed as nodes of networks.  

Edge servers may be smaller than cloud data centers, but they have the same purpose: to store and process data. Additionally, while cloud data centers are centric to a system, edge servers are distributed. The top edge servers and edge computing providers include Microsoft, IBM, Amazon Web Services (AWS), Google Cloud Platform, NVIDIA, Dell, and others.   

Types of edge servers

• Device edge: Components or attachments of an end-user device
• On-Premises edge: Nodes physically located in the network or facility
• Network edge: Network-specific nodes like base stations and telco data centers 
• Regional edge: Traditional data centers serving the largest geographic regions

How Does Edge Caching Work?

Edge caching works by moving regularly accessed resources closer to the end user accessing them, mitigating deductive or reduplicative network traffic and speeding up load times.

To accomplish this, data centers, edge servers, and local memory components work together to create a memory hierarchy. 

Though traditional data centers have the largest capacity, their resources in the edge computing landscape are accessed the least by network end users. Edge servers, on the other hand, have less capacity but store more frequently used resources. 

Finally, local storage has the least storage space but contains the contents and resources needed the most often. 

When deployed effectively, edge caching enhances endpoint performance while relieving remote data centers of added stress with load balancing.

Caching in action: Web browsers

For most end users, web browsers are the most visible example of caches in action. Caches for web browsing, including edge caching, typically follow these steps:

1. The end user navigates to a specific website or application.
2. The web browser downloads content to display to the user.
3. The user visits the same website at a later time or date.
4. The browser retrieves the original website’s content from cached memory, rather than having to download all of the data again.
5. The browser scans the webpage for any new content and updates the resource as necessary.

Instead of reloading the static contents of a webpage every time the user visits, caches allow for the adaptive updating of new, dynamic content. The same principles are applied in edge caching. 

Benefits of Edge Caching 

From speed and efficiency to security and reliability, edge caching has numerous benefits. 

Edge caching can: 

• Improve performance and reduce latency. 
• Power real-time responses for various applications, from autonomous vehicles to livestreaming, social media, or e-commerce.
• Reduce bandwidth and improve security. 
• Deploy efficient algorithms to reduce the amount of data that needs to be transferred. 
• Optimize data structures to improve the performance of queries. 
• Leverage parallel processing and distributed computing to improve the scalability of edge computing systems.

Drawbacks of Edge Caching 

Edge caching is a great way to improve a network’s performance and scalability, but it does have some drawbacks. 

The most common challenges of edge caching include:

• Storage and configuration: Caches have storage limitations and configuration complexities. Administrators or users will typically need to clear space or reconfigure the cache to restore functionality after a malfunction.
• Increased cost: Edge caching requires the deployment of additional hardware and software, which can increase the cost of a network.
• Increased complexity: Edge caching can add complexity to a network, making it more challenging to manage and maintain.
• Reduced control: Edge caching can reduce a network administrator’s control over the network, as decisions about caching are made at the network’s edge.

Where and How Is Edge Caching Used?

Edge caching is deployed through several different types of edge servers—including CDNs, wireless, and IoT servers—to a variety of industries, from smart manufacturing facilities to retail touchpoints and healthcare centers.

Edge caching servers

The most common types of edge servers include:

• CDN edge servers: CDN edge servers are used to deliver content, such as web pages, videos, and images, to end users. They are typically located in strategic locations around the world where the CDN’s users are more heavily concentrated.
• Wireless edge servers: Wireless edge servers are used to provide connectivity and computing resources to wireless devices, such as smartphones, tablets, and laptops. They are typically located at the edge of a cellular network.
• IoT edge servers: IoT edge servers are used to collect and process data from IoT devices, such as sensors and actuators. They are positioned close to the IoT devices.
• Edge computing servers: Edge computing servers perform compute-intensive tasks at the network’s edge. They are positioned close to the end users..

The type of edge server that is best for a particular application will depend on several factors, including the type of content being delivered, the location of the end users, and the application’s performance requirements.

Industries that use edge caching

Industries and new technologies that use edge cache include: 

• Smart factories and manufacturing facilities
• Warehouses
• AI and machine learning (ML)
• Biometrics (face and fingerprint ID)
• Agritech
• Augmented and virtual reality (AR and VR)
• Smart cities
• Robotics, IoT, and Industrial IoT
• Retail touchpoints
• Energy
• 5G and Open RAN
• Healthcare
• Defense

Hardware vs. software edge caches

Additionally, edge caching can be created physically as hardware caches or deployed virtually as software caches, each with pros and cons. 

Developers must evaluate the costs, complexity, security, and performance of software versus hardware caches before deciding the best fit for their use case. 

Software caches examples include: 

• Operating systems
• Domain name systems (DNS)
• Databases
• Web app servers

Hardware caches can be: 

• CPU or GPU
• Hard disk drives (HDDs)
• SSDs

Bottom line: Edge caches enable the modern network

Without edge computing, the digital world as we know it and the online services billions of people use every day would not exist. Where data is located and how fast it can be processed and transferred has become vital for our society, and edge caching is widely responsible for making this happen. 

As the amount of data the world generates continues to increase, edge computing and edge caching will only grow more necessary for our highly innovative digital ecosystem. The expansion of edge infrastructures will continue to expand caching capabilities, enabling ever faster and more dependable delivery.

Sam Ingalls contributed to this guide.

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