Every second counts when it comes to keeping users engaged online. During traffic surges, delivering a seamless experience is critical. A content delivery network (CDN) ensures fast, reliable access to web content by distributing it across servers located near end users. This reduces latency, improves load times, and helps maintain the performance and reliability of websites and applications—regardless of user location.
Over time, organizations often end up with more than one CDN. The organization may have acquired a second one through a merger or may be considering a multi-CDN strategy to improve performance and operations.
By understanding how a single CDN improves the end-user experience and the challenges of maintaining one, organizations can make an informed decision about implementing a single or multi-CDN strategy.
What is a CDN?
A Content Delivery Network (CDN) is a network of servers designed to deliver internet content quickly to users. It works by caching content on edge servers located around the world. This setup reduces load times by minimizing the physical distance between the user and the server that has the content.
CDNs help organizations reduce bandwidth consumption and lower bandwidth costs. By storing both static and dynamic content closer to users, CDNs ensure faster load times. This improves user experience, even during traffic spikes when demand for online content is high.
What Does a Content Delivery Network Do?
By caching and delivering content from servers located geographically near the end-user, CDNs improve content availability and provide a more responsive and reliable online experience.
High-Speed Content Delivery
CDNs store cached content on edge servers situated at points of presence (PoP) near users. Since this reduces the physical distance data travels, CDNs cut down latency and speed up load times. With traffic distributed across multiple servers, no single server becomes overwhelmed by requests, so the setup improves availability during high-traffic periods. Additionally, CDNs reduce bandwidth consumption and costs by reducing the origin server’s data transfers.
Real-Time Streaming
Real-time streaming services use CDNs to prevent buffering. They ensure a smooth user experience across nearly all industry verticals, including:
- Entertainment: improving streaming for videos, games, and music
- Education: enabling online learning environments that host course materials and live virtual classes
- New media: improving delivery of updates during heavy traffic
- Financial services: loading banking and investment applications
Multi-User Scaling
CDNs effectively scale to handle traffic surges during peak periods so organizations can manage server expenses efficiently. Caching content in a geographic location closer to the audience reduces origin server data transmissions, which lowers infrastructure costs and expands end-user reach. As CDNs improve content load times, organizations gain benefits like:
- Increased page views
- Better customer engagement
- Lower site abandonment
- Improved search engine rankings
- Boosted organic traffic and exposure
How Do CDNs Work?
CDN distributes a website’s content across a network of servers worldwide. These servers, known as edge servers, help route users to the most efficient path to load content.
Caching
Caching involves storing static content on multiple servers. Some examples of static content include:
- Images
- HTML files
- JavaScript files
- CSS files
When a user requests content, the request goes to the geographically closest server, reducing the distance it has to travel and sending the cached content back to the user. This process typically involves:
- Origin server interaction: The origin server sends a copy of the content request to the nearest CDN point of presence (POP) for caching.
- Edge server delivery: The cached content stays at the edge servers, geographically distributed servers, which improves load times and reduces the load on the origin server.
Dynamic acceleration
Dynamic content relies on user-specific data, so caching won’t work. However, CDNs optimize the delivery of dynamic content by identifying the most optimized route between edge servers and the origin server. The process looks like this:
- User sends a request.
- Request goes to the geographically closest edge server.
- CDN identifies the fastest route from the edge server to the origin server, forwarding the request there.
- Origin server responds to the edge server using the fastest route.
- Edge server sends response to the user.
By identifying the fastest route across all these connections, the CDN reduces load times.
What Is the Difference Between a CDN and Web Hosting?
A Content Delivery Network (CDN) and web hosting serve content to users but work differently. Web hosting uses a single server to deliver the entire website from its origin server. This approach can increase load times due to the physical distance between users and the server.
In contrast, a CDN uses a network of servers, known as edge servers, positioned in various geographical locations. This setup helps deliver content faster by reducing latency. CDNs often complement traditional web hosting to improve performance and customer experience, leading to higher website engagement.
What Are the Challenges of a Single CDN?
Operating with a single CDN means that the organization may over-rely on a single provider that can impact the operations and the end user’s experience.
Setup and Configuration Complexity
Often, setting up and configuring a CDN requires technical experience since the organization needs to modify DNS settings and integrate the CDN with its content management systems. For example, optimal performance requires configuring the caching and content delivery settings, which can include configuring:
- Metadata: setting attributes like content type for rendering content, cache control for determining how long browsers and caches store the content’s copy, content encoding for compressing files, and content disposition for file display
- Domains: creating zones, updating the registrar’s domain settings to point to the appropriate name servers, selecting the origin load balancers
- Distribution type: selecting how to distribute content, like using HTTP Distribution, HTTPS Distribution, or HTTPS with custom certificate distribution
Dependency on a Single Provider
Relying on a single CDN provider introduces significant risks that can include:
- Service disruption arising from a technical issue or cyber attack
- Provider network problems that impact access to DNS records
- Lack of customer support unless using a higher-paid subscription tier
Performance Limitations
While a CDN should improve website performance, using a single provider can undermine this benefit. Some examples of how relying on a single CDN provider can reduce performance include:
- Degraded user experience from cache hit rates
- Delays updating dynamic content performance from a lack of real-time cache invalidation
- Service disruptions from cache poisoning that replaces relevant content with useless data
- Delivery failures from incorrect CDN configuration settings that lead to cache misses and delivery failures
Considerations for a Multi-CDN
A multi-CDN strategy enables organizations to optimize their CDN using several providers, increasing agility and flexibility. By leveraging multiple CDN vendors, companies can enhance their reach and reliability across different geographic locations. Organizations relying on a single CDN provider should consider these technical and operational issues to determine whether a multi-CDN makes sense for their business objectives.
For a deeper dive, check out The Benefits of Multi-CDN.
Technical Considerations
Choosing a single content delivery network can expose companies to various technical challenges. With a multi-CDN implementation, organizations have a backup option if a CDN Provider experiences a security issue that can threaten content delivery and user data protection, like misconfigurations and Distributed Denial of Service (DDoS) cyberattacks. With a multi-CDN, the organization eliminates the single point of failure and the risk of complete service disruption if technical malfunctions or outages occur.
Operational Considerations
Using a multi-CDN architecture, organizations can improve performance by using providers to cover more geographical areas. Additionally, a multi-CDN strategy is more flexible and scalable, enabling the organization to manage traffic spikes and adapt to changes quickly.
UltraDNS: Intelligent Real-Time Traffic Routing to Optimize Performance
UltraDNS uses a robust network of monitoring nodes and real user data to automate routing and identify the fastest provider in each region. We automatically update your DNS records to point to the fastest one for huge performance gains, even when CDNs share the same PoPs. Our CDN load-balancing services include built-in failover and outage recovery so that you can seamlessly migrate traffic to backup providers to prevent downtime and reduce business interruption. With our global GeoDNS capabilities, you can build your own custom configurations or use our traffic steering capability to dynamically route users to the fastest servers in their region or for their specific location or network.
