What is a CDN? How does a CDN work?

Introduction

People connect to websites and applications from various corners of the world to access the content. However, if the website’s servers are based in one location, for instance, New Delhi, people beyond the city boundaries might experience sluggish content rendering compared to those within the city. And this increases the chances of the consumers abandoning these web pages due to slow load times. To speed up the web assets, businesses need Content Delivery Network (CDN) services 

This article discusses the basics of CDNs and how they help businesses ensure easy, efficient, and seamless content delivery to their end users.

What is a Content Delivery Network?

CDNs are somewhat in line with an automated teller machine (ATM). Having a cash dispenser on practically every corner makes it easy and fast for people to withdraw money. There are no waiting periods in long bank queues, and the ATMs are stationed in multiple convenient locations for immediate access.

A CDN is a group of servers dispersed across geographies that team up to deliver a stable content access experience to end-users quickly, securely, and efficiently. This geographically distributed server network allows companies to keep a copy of their websites’ content closer to their customers.

A CDN can deliver types of digital content, including 4K and HD videos, audio streams, and software downloads such as applications, games, and OS upgrades.

What is a CDN used for?

When you access a website, instead of all the content coming from a single server, a CDN ensures it is delivered from a server closer to your location. This efficient setup not only enhances the performance of websites but also guarantees their availability even during high traffic, providing a sense of reassurance to web developers, IT professionals, and business owners.

Here are some of the primary uses of a CDN:

Faster load times

A CDN caches (stores) content on servers that are geographically close to the user. This means that frequently accessed data, such as images and videos, is stored on these servers, reducing the distance the data needs to travel and speeding up the loading time of web pages. When websites load faster, it improves the user experience, potentially increasing conversions and reducing the likelihood of visitors leaving the site (bounce rate).

Reduced bandwidth costs

Without a CDN, all content has to be served from the central server, which requires a lot of bandwidth (the amount of data transferred over a network). CDNs reduce this load by caching static content (files that don't change often, like images and videos) and serving it from their servers. This optimisation not only speeds up content delivery but also helps reduce bandwidth consumption, making it a prudent and business-savvy choice for businesses.

Improved availability and redundancy

When all content is served from a single origin server, the risk of downtime (periods when a site is unavailable) increases due to potential hardware failures or network issues. A CDN, with its distributed content across multiple servers in different locations, ensures that if one server fails, another server can seamlessly continue to deliver the content, instilling a sense of security and confidence in website availability.

Enhanced website security

CDNs also improve website security. They can protect against distributed denial-of-service (DDoS) attacks (where a website is overwhelmed with traffic to make it unavailable) and help secure sensitive data through features like better management of digital certificates (which encrypt data to keep it secure). This reduces the risk of cyberattacks, making your website safer for users.

What is the history of CDN technology?

CDNs have played a critical role in improving how content is delivered across the internet. As online data grew rapidly, producing large volumes of content quickly and efficiently became challenging. CDNs emerged as the solution, continuing to evolve as technology advances.

Here's a breakdown of the history of CDN technology:

Pre-formation period

The foundations of CDNs were laid in the early days of the internet with the development of technologies like server farms (groups of servers working together), caching (storing frequently accessed data for quicker access), and multihoming (connecting to multiple networks for reliability). These innovations helped websites manage large amounts of data and provided the starting point for CDNs to grow.

First generation of CDNs

The first generation of CDNs focused on delivering static and dynamic content (content that does not change frequently versus content that updates regularly) more efficiently. This was done by creating content replicas across multiple servers and using intelligent routing (directing data in the most efficient path) to reduce load times. This era significantly improved web performance as content was distributed closer to users.

Second generation of CDNs

With the rise of Video-on-Demand (VoD) services, the second generation of CDNs shifted focus to streaming video and audio content. During this period, delivering content to mobile users became a priority, revolutionising how people consumed media.

Technologies like P2P (peer-to-peer networks), where users share data directly with each other, and cloud computing (remote servers that store and manage data) were introduced to further improve content delivery and storage.

Third generation of CDNs

The third generation of CDNs is still in development but is expected to focus on community-driven content delivery, where everyday users play a role in managing and distributing data.

These systems are expected to be self-configuring and self-managing, meaning they will automatically adjust and optimise their operations. This generation aims to improve the overall quality of experience (QoE) for users by making CDNs more adaptable and efficient.

Is a CDN the same as a web host?

CDN) and web hosting serve different but complementary roles in delivering content to users online. While both involve similar technologies, understanding their unique functions can help you optimise your website's performance.

What is Web Hosting?

Web hosting is the service that allows you to store your website's files on a server, making them accessible on the internet. When someone visits your website, their browser connects to your web host's server, typically located in a single physical location, to retrieve the content. This means that if a user is far from that location, it may take longer for your website to load, causing delays.

What is a CDN?

A CDN is a network of servers located in various geographic areas. It helps deliver content more quickly by caching (storing copies of) your website's data closer to users. When a user requests content, the CDN serves it from the nearest server, reducing the time it takes for the data to travel. This improves loading speeds and overall user experience.

Differences between CDNs and web hosting

While both CDNs and web hosting are essential for a website's performance, they differ in several key ways:

• Server locations: Web hosting typically uses a single server location, while a CDN employs multiple servers around the globe. This means a CDN can serve your content from a location much closer to your users, speeding up delivery.
• Content delivery: Web hosting delivers all types of content directly from the server. In contrast, a CDN primarily serves static content (files that do not change often, such as images and videos). By offloading this static data, a CDN reduces the load on your web host, allowing it to function more efficiently.
• Reliability: CDNs increase reliability by providing backup options. If one server fails, another nearby server can take over, minimising downtime. With traditional web hosting, if the primary server goes down, your entire website may become inaccessible.

Why use a CDN with web hosting?

Using a CDN alongside your web hosting service can significantly improve your website's performance. CDNs help reduce bandwidth costs by caching content, preventing interruptions by distributing data across multiple servers and enhancing security features against attacks.

How do CDNs work?

To minimise the distance between visitors and a business’s website, CDNs create a copy of the web assets (Caches) in several geographical locations - points of presence (PoP). Each PoP entails loads of caching servers responsible for web content delivery to visitors within its radar.

CDNs store and safeguard these cached files of the online content, including images, live videos, JavaScript files, and HTML pages, on hard-disk and solid-state drives (HDD and SSD) or in random-access memory (RAM).

So when another visitor within the same geography browses the website, CDNs forward the request from the origin server to the nearest server (edge server). That server then delivers the cached content significantly faster as it has less distance to traverse.

However, this is not the only way that CDNs serve material more rapidly and reliably.   

A real-world illustration to explain how a CDN works would be to view online traffic in the same way as actual traffic. Assume there is more than one route from point A to point B. In the event of congestion, it is better for everyone to spread the traffic over a few different courses, even if there is a preferred route. While this may result in a path that is a few minutes (or microseconds, when scaled to internet speeds) longer, it prevents you from being caught in the traffic congestion building up on the quickest route. It is also possible that you will be sent along the shortest way after other vehicles have been routed differently. Thus, CDN works by balancing the load and maximising all available resources. 

Besides speeding up web content delivery, CDNs also safeguard the business’s website as they reside in front of the backend server. They can act to effectively block cyberattacks and handle the incoming traffic flow to balance the load on each server.

It's little wonder that CDNs have been the hidden backbone of the internet for more than 20 years, providing online information for commerce, banking, healthcare, and other companies rapidly and at scale.

Who uses CDNs?

CDNs were designed to give all internet users a speedier and more consistent experience. Some use cases are as follows:

CDN for end users

Through a CDN, end users benefit from quicker page loads, more straightforward transactions, and a more stable online experience. Since the technology operates invisibly, users may not realise they are connected via a content delivery network. From their perspective, they are simply receiving content from their ISP or mobile provider.

CDNs for content publishers

Content and application owners, such as eCommerce sites, media assets, and cloud computing firms, utilise CDNs to enhance the user experience, decrease abandonment, increase ad impressions, boost conversion rates, and reinforce customer loyalty. Using a content delivery network may also improve online security, for instance, by helping to absorb and neutralise a Distributed Denial-of-Service (DDoS) assault.

CDNs for service providers

Online streaming and other rich media services have explosive growth and higher user expectations regarding web performance across various device types. Many network service providers deploy via CDNs to minimise subscriber churn, stimulate the development of value-added services, and reduce traffic on the core network. CDN services can benefit companies and third-party content owners.

Five main benefits of CDNs

The surge in Internet usage for media and data transfer and increasing consumer shift toward over the top (OTT) content and video on demand (VOD) has pushed the demand for CDN services worldwide.

As such, the capability of CDN solutions to decrease hosting bandwidth by using the cache, and thus, curb the risk of low quality or service interruptions, has become quintessential for broadcasters to keep up with the phenomenal appetite for new and different content.

Let’s look into why businesses should kick-start their CDN journey.

Improve website loading time 

CDN solutions are immensely beneficial for businesses that depend on their websites to deliver content rapidly. Organisations can achieve this by caching content on the CDN servers nearest to the end-users.

When a visitor requests content or a page on the website, they do not need to wait for the request to reach the origin server. Instead, they can access the content from the servers closest to them, minimising the delay for the visitor and boosting the business’s website performance.

Deliver richer visual experience faster

An excellent website experience depends on quickly delivering high-quality content, images, and other visual assets to the users. Whether an organisation serves a few hundred or several million photos each month, CDN can help them deliver the contentin a more efficient and effective way. The right CDN service can also automatically resize, compress and convert original large images into optimised versions that are tailored to specific requesting devices. This improves customer experience across mobile devices and allows organisations to build faster websites, reducing page load by a significant margin.

Enhance content availability

With higher traffic volumes comes the higher pressure placed on the origin servers to prevent the websites from collapsing and keep the content intact. CDNs absorb all this traffic and scatter it across their distributed infrastructure, enabling businesses to level up their content availability regardless of the load. Moreover, if any server goes down, other PoPs can handle the traffic and ensure seamless service.

In addition, some top-notch CDNs automatically detect the availability and instantly forward requests and users, also called load balancing, which ensures high levels of availability at any time.

Optimise content across devices

Today’s consumers have an increasing number of connected devices, a changing set of preferred specifications and expectations, and a variety of network conditions that may affect the experience they receive. It is critical to ensure that digital assets are delivered fast to all the right devices, regardless of the location or access network. CDN solutions that address these challenges with a focus on the ‘last mile’ will enable you to reach consumers wherever they may be. In short, a CDN makes it possible for your sites to serve visitors on mobile devices. This helps to ensure that an organisation’s mobile visitors are able to load their site more quickly, which will encourage them to keep visiting your site more often.

Resilience against cybercrime

CDNs are particularly well-suited to keep away cyberattacks, mainly Distributed Denial-of-Service (DDoS), which depend on sending traffic spikes to critical servers. In these attacks, the cybercriminals try to swamp and crash a vital server by directing large volumes of junk requests to that server.  

A CDN service brings peace of mind for organisations. With advanced tools and best practices that ensure maximum availability and resilience, it ensures digital properties are safe against cyberattacks. Furthermore, integrated well with DDoS, WAF, and DNS security, a CDN solution is a perfect solution for enterprises to protect their web properties all the while also preserving performance gains.

Reduce bandwidth costs

Bandwidth consumption expenses can swell for a website, primarily for those using numerous rich media. However, through caching at the edge server, CDNs can slash the data volumes that the hosting server must provide. In many cases, this curbs the bandwidth and hosting expenses of small- and medium-scale businesses (SMB), freeing up valuable resources for other purposes.

Offload network traffic

By responding to a request for web content with a cached version in closer physical and network proximity to the end user—instead of from the server where the content originates—a CDN offloads traffic from content servers and improves the web experience. As a result, the content can stay within the network operator's network and reduce the need to interact with other networks or navigate the broader internet to deliver information.

Provide consumer insights

Since CDN providers transfer more than half of the world's internet traffic, they collect massive amounts of data about end-user connectivity, device types, and browsing experiences. By providing their clients with critical, actionable insights and knowledge about their user base, they may be able to help them improve their business. As part of these services, end users may be monitored and analysed in real-time to determine how they interact with web content.

Increase audience reach and scale effectively

These benefits, when put together, help organisations reach a considerably bigger global audience using CDN services.

As mentioned, CDNs are a more effortless and cost-efficient solution to provide content to visitors in geographic coordinates far off from the headquarters of a company and its origin servers.

Also, they help deliver a consistent customer experience for end-users. Keeping customers satisfied this way will result in a domino effect and boost audience expansion, effectively letting businesses enter new markets.

Tata Communications CDN services allow an organisation’s visitors to enjoy faster load times for rich web content and applications. Sacrificing site performance is no longer an option with our CDN Web Site Acceleration (WSA) solution.

Besides, the Tata Communications CDN also shields your website and users’ data from cyberattacks by providing a Web Application Firewall (WAF), holistic DDoS guarding, and DNS security.  With Tata Communications CDN services, fast content delivery is just a few clicks away. The net result? Lightning fast, reliable, and secure connections 24/7 for end-users worldwide.

Conclusion

In conclusion, a CDN is essential for optimising the delivery of web content, enhancing performance, and improving user experience. By caching data closer to users, CDNs significantly reduce load times, increase reliability, and provide a robust security framework.

Plus, with the increasing demand for rich content, Tata Communications ensures your website delivers high-quality experiences at blazing speeds. Their CDN-backed services enhance web browsing by optimising load times, which reduces bounce rates and drives higher conversions. Schedule a demo now to know more!