Introduction to the Content Delivery Network (CDN)

You might not be aware, but you are interacting with content delivery networks every day. Content delivery networks (CDNs) are the Internet's transparent backbone for content distribution. 

 

When we read articles on news sites, shop online, watch YouTube videos, or scroll through social media feeds, we interact with CDNs. CDNs are behind every word of text, every picture pixel, and every movie frame sent to your PC and mobile browser, regardless of what you do or what sort of material you receive.

 

What exactly are content delivery networks? We will find out in this article.

 

What is a CDN?

 

A content delivery network (CDN) is a collection of geographically spread computers that speeds up online content delivery by bringing it closer to consumers. Caching, a practice that temporarily saves copies of information in data centers across the world, allows you to access online material via a web-enabled device or browser more quickly through a server near you. This is accomplished by delivering material closer to users' geographic locations via strategically situated data centers known as Points of Presence (PoPs).

 

Web pages, pictures, and videos are cached by CDNs on proxy servers near your physical location. This eliminates the need to wait for content to load before watching a movie, downloading software, checking your bank balance, posting on social media, or making transactions.

 

To understand CDN, you can compare it with an ATM. Having a cash machine on almost every corner makes getting money quick and easy. There are no long bank lines, and ATMs are located in a variety of accessible places for quick access. CDN services are critical for organizations that rely on users receiving material, such as:

 

• Large news organizations with a global audience

• Users' feeds on social networking platforms that need to offer multimedia material

• Netflix and other entertainment websites are offering high-definition online material in real-time.

• Millions of clients on e-commerce platforms

• Gaming firms with graphics-intensive content that is viewed by customers from all around the world

 

All of these companies must guarantee that their information is delivered quickly, that services are available, that resources are scalable, and that web applications are secure. CDN services emerge as a distinct benefit in this situation.

 

The History of CDN:

 

Since the 1990s, commercial CDNs have existed. They passed through multiple evolutionary phases before becoming the strong application delivery platform they are today, just like any other decades-old technology.

 

Market pressures, such as new patterns in content consumption and significant connection developments, impacted CDN development. Fiber optics and other modern communication technologies have permitted the latter.

 

Overall, there are three generations of CDN evolution, each of which introduces new capabilities, technologies, and concepts to the network architecture. Working in tandem, each iteration saw CDN service pricing fall, signaling the technology's metamorphosis into a mass-market technology.

 

• The technology and infrastructure needed for CDNs were being developed prior to their actual creation. The growth of server farms, hierarchical caching, advancements in web servers, and caching proxy deployments defined this time. Mirroring, caching, and multihoming were additional technologies that helped CDNs get started and thrive.

 

• The original generation of CDNs largely focused on dynamic and static content distribution, as these were the only two forms of material on the web at the time. The construction and implementation of replicas, intelligent routing, and edge computing technologies were the main mechanisms at the time. Apps and data were distributed over several servers.

 

• The second generation of CDNs focuses on streaming video and audio material, as well as video-on-demand services such as Netflix for consumers and news services. This generation also witnessed the application of P2P and cloud computing techniques, as well as the delivery of website content to mobile users.

 

• We are presently in the third generation of CDNs, which is continually changing due to fresh research and development. We may anticipate CDNs to become more community-oriented in the future. This means that the systems will be driven by ordinary people. Self-configuring, as well as self-managing and autonomic content delivery, are projected to be the future technical mechanisms. Going ahead, the key driver is likely to be the quality of the end-user experience.

 

Also Read | A Gentle Introduction to Video Streaming Technology

 

Are CDN hosts and Web hosts the same thing?

 

Although content delivery network servers are geographically spread to cache material closer to users and their ISPs wherever they are in the globe, CDNs are not web hosts and do not carry products across the last mile to consumers. This temporary content storage at the network edge allows for lower latency and more efficient delivery of the same material to many consumers.

 

A CDN hosting platform may be a very effective and cost-effective option for network operators, also known as wireless service providers or mobile network carriers, who are trying to keep up with the never-ending demand for online video. On every web-enabled device, a content delivery network can enable operators to provide a quick, secure, and reliable online experience with the constant quality that users demand.

 

How do CDNs work?

 

Latency is the irritating wait you get while trying to view a web page or video stream on your device before it is fully loaded. Even though it's measured in milliseconds, it might feel like an eternity, and it could cause a load error or time-out. A CDN's purpose is to minimize latency.

 

Some content delivery networks reduce latency by shortening the distance that material must travel to reach you. As a result, larger, more widely spread CDNs may provide online material more rapidly and reliably by placing it as near as feasible to the end-user.

 

How does a CDN improve Latency?

 

When it comes to websites loading content, visitors leave quickly if the site takes too long to load. CDN services can aid in load time reduction in the following ways:

 

• Because a CDN is globally dispersed, it reduces the distance between users and website resources. Instead of connecting to the origin server of a website, a CDN allows users to connect to a data center that is closer to them. Faster service equals less travel time.

 

• Data may be delivered quicker using hardware and software innovations such as efficient load balancing and solid-state hard drives.

 

• By lowering file sizes with techniques like minification and compression, CDNs can minimize the quantity of data delivered. File sizes that are smaller load faster.

 

• By minimizing connection reuse and allowing TLS false start, CDNs may help speed up sites that use TLS/SSL certificates.

 

A CDN maintains a cached version of original material in various geographical locations (a.k.a. points of presence/ PoPs) to reduce the distance between users and your website's server. Each PoP has a number of edge servers, which are responsible for delivering content to visitors in its immediate vicinity. Content is cached in many locations at once, guaranteeing rapid delivery.

 

Let us look at two cases, one without a CDN and one with a CDN.

 

Without a CDN:

 

When a person visits a website without using a CDN, he establishes a connection similar to the one shown in the diagram. The Local DNS or LDNS converts the website name to an IP address (such as the DNS server provided by the ISP or a public DNS resolution server). If DNS or LDNS is unable to resolve the IP address, it will recursively seek resolution from upstream DNS servers. Finally, the request may be sent to the authoritative DNS server that hosts the zone. The address is resolved and returned to the user by this DNS server.

 

The user's browser then establishes a direct connection with the origin and downloads the website content. The origin serves each successive request directly, and the static assets are cached locally on the user's system. If a person from a similar or different location attempts to visit the same site, the same procedure will be followed. User requests will be sent to the origin every time, and the origin will respond with content. Each step adds a delay, or "latency," to the process. Response times will suffer from high latency if the origin is located far away from the user, resulting in a bad user experience.

 

With a CDN:

 

The approach is slightly different in the presence of a CDN. When his LDNS receives user-initiated DNS queries, it sends the requests to one of the CDN's DNS servers. The Global Server Load Balancer (or "GSLB") architecture includes these servers. The GSLB aids load balancing functionality by measuring the whole Internet and keeping track of all accessible resources and their performance. The GSLB uses this information to resolve DNS requests by utilizing the best-performing edge address (usually in proximity to the user). A group of servers known as "edge" caches and distributes online information.

 

The user sends an HTTPS request to the edge when DNS resolution is complete. When the edge gets the request, the GSLB servers assist the edge servers in forwarding the request to the origin through the most efficient path. The edge servers then get the required data, send it to the end-user who made the request and store it locally. Without having to ask the origin server again, all subsequent user requests will be delivered from the local dataset. Even if the original becomes inaccessible for whatever reason, content stored on the edge can be transmitted.

 

Also Read | What is Semantic Web?

 

Benefits of CDNs:

 

Although the advantages of utilizing a CDN change based on the size and demands of an Internet site, the key advantages for most users may be divided into four categories:

 

1. Visitors benefit from quicker page loading times by delivering material closer to them by utilizing a nearby CDN server (among other enhancements). A CDN may minimize bounce rates and enhance the amount of time people spend on a site, since visitors are more likely to click away from a slow-loading site. In other words, a speedier website will attract more people who will remain longer.

 

2. The cost of bandwidth used for website hosting is a major expense for businesses. CDNs can minimize the quantity of data an origin server needs to offer through caching and other improvements, lowering hosting costs for website owners.

 

3. Large quantities of traffic or hardware breakdowns might cause a website's usual operation to be disrupted. A CDN can manage more traffic and resist hardware failure better than multiple origin servers because of its dispersed nature.

 

4. DDoS mitigation, enhancements to security certifications, and other optimizations may be provided by a CDN.

 

Why do we need CDNs?

 

The internet may come to a halt if CDNs, with their capacity to copy and store information from origin servers and subsequently provide digital material near to where consumers access the internet, were not available. If you've done practically anything online, you've undoubtedly used a CDN to get a quick, consistent, and reliable experience.

 

A CDN balances total traffic to provide the best possible online experience for everyone accessing internet content. Consider how traffic is routed in the real world. If there are no other cars on the road, one route may be the fastest from point A to point B — but if it becomes crowded, it is best for everyone if traffic is spread out across several routes. This may result in you being sent along a road that takes a few minutes longer (or microseconds when scaled to internet speeds), but you won't get caught in the traffic congestion that's building on the fastest route.

 

It might also mean that you'll be sent on the shortest usual route possible, but without being stuck in traffic, because other vehicles will be routed on longer routes. So it's not about slowing down; it's about load-balancing and making the most of all available resources.

 

 

Bottom Line

 

A CDN is used by almost everyone who accesses the internet. They were developed to give users a more stable and speedier internet experience. Content and application owners, as well as network service providers who deliver such advantages to their clients, utilize them.

 

However, the CDN's advantages are not limited to those listed above. Your business and engineering teams will benefit greatly from a modern CDN platform. It may be used to control access from various parts of the globe. You can provide access to specific places while denying access to others.