Speed: It’s what everyone in our industry ultimately craves. When networks are fast, many things happen: work is completed quickly, customers are happier, frustrations are kept to a minimum and unplanned downtime doesn’t negatively impact business performance.

In our conversations about speeding up networks, one phrase is becoming more common: content delivery network (CDN). Content delivery networks can enhance network performance across the globe in a simple platform. Here, we explain what a CDN is, why it’s being used and how it impacts speed and bandwidth.

What is a Content Delivery Network?

A content delivery network is a system of strategically placed servers around the world, working together to connect large numbers of users – through the Internet – to original content. Content is duplicated on several intermediate content servers and edge servers located closer to where users are.


Content delivery network systems are spread across different geographic regions, widely used by web portals and internet service providers (ISPs) to cache and offload dynamic or static web pages.

Each CDN node (edge server) caches static content; when a user heads to a website, the edge server closest to him or her is the one that delivers the static content. This allows the data to travel the shortest distance possible, reducing latency (delays) and speeding up page-load time.

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Bandwidth and Availability

Today, content delivery network bandwidth requirements are exploding as these networks deliver data storage and audio/video streaming services from cloud service providers (CSPs) and original content providers. Most of this growing traffic is contributed by over-the-top (OTT) service providers, such as Netflix, YouTube and iTunes, among others. (OTT involves internet delivery of audio, video and other media without involving a multiple-system operator controlling or distributing the content.)

Instant availability is very critical to most OTT businesses, but limited bandwidth availability can give rise to traffic congestion and latency issues. For an organization that depends on website performance, load time and delays can often be catastrophic. This is even truer for global content owners and cloud service providers, such as Amazon, Google, Facebook and Microsoft, which face increasing competition and very demanding customers.

Content Delivery Network Adoption Expands

chart depicting global internet traffic downstream

chart depicting global internet traffic upstream

If we examine global internet traffic today, video on demand consumes more than half of the total bandwidth available. With the new video format transition from 1080p HD to 4K UHD, more advanced smartphones uploading billions of pictures daily and the impact of the Internet of Things (IoT), CDNs will play a more important role in the expanding internet ecosystem.

The adoption of CDN is expanding exponentially as major vendors aggressively invest in their network infrastructure to optimize content delivery while looking for cost-effective solutions that offer lower prices and better experiences and service.

In addition to offering improved performance through content traveling shorter distances, a content delivery network can also help manage spikes when traffic is offloaded to a CDN. Reliability improves as well; if the closest server to the user isn’t available, requests are automatically sent to the next closest (and available) server.

Who’s Using Content Delivery Networks?

Although OTT content delivery consumes most of the CDN bandwidth, the margin is relatively low due to the high costs and high competition associated with CDN solutions. Today, CDN service providers have to combine bandwidth with adjacent/embedded solutions, such as security, DRM (digital rights management), PCI compliance, load balancing and asset monetization, into their service packages to enable and optimize clients’ business processes and workflows.

The leading traditional CDN companies, such as Akamai, CDNetworks, ChinaCache, ChinaNetCenter, CloudFront, and Limelight Networks, along with telco CDNs, such as Level3, Tata Communications and Verizon (EdgeCast), are selling CDN caching capabilities as standalone packages, while cloud CDN providers, such as AWS and Microsoft Azure, are offering the CDN as a feature within digital acceleration services.

According to MarketsandMarkets, the global CDN market size is expected to grow from $4.95 billion in 2015 to $15.73 billion in 2020, at a CAGR (compound annual growth rate) of 26%. CDNs are also growing fast in cloud computing, internet/cloud security and mobile clouds. Other crossover markets include the multiprotocol label switching (MPLS) market to serve the coming WAN-as-a-service providers, as well as the cloud radio access network (cloud RAN), as the number of connected mobile devices and IoT both explode in the next few years.

How will enterprises benefit from a content delivery network? Is it something you need to look into? Belden can answer all of your network questions. Learn more here.

Were you familiar with content delivery networks before reading this blog? Would you like to learn more in future articles? Let us know in the comments section below!