How Does a CDN Work: Principles, Setup, and Tips to Boost Site Speed

What is a CDN (Content Delivery Network)?

A Content Delivery Network (CDN) is a system of servers located around the world that speed up content delivery. For example, if your site is hosted in Canada and a visitor from Ukraine browses it, it will take a long time for the data to travel back and forth without a CDN. With a CDN, the data will already be stored and waiting for the Ukrainian visitor in Kyiv.

How Does It Work?

• Static Files: Images, CSS, JS—cached on the nearest servers, which means they load almost instantly even if the visitor is overseas.
• Dynamic Content: CDN optimizes requests through smart routing, sending users' requests via the shortest, most efficient route available.
• Media: Videos and podcasts are distributed across servers.

You can picture CDN as a global highway for your content.

Principles of CDN Operation

Servers Worldwide
At Hostiserver, we have launched over 100 Points of Presence (PoPs) in Europe, the US, and Asia; a user based in London connects to a UK PoP; a user in Sydney connects to an Australian PoP. Studies like CDNPerf show CDNs typically reduce latency by 50%, with other studies showing reductions of up to 75% for global projects depending on where the server is located and how it is configured.

Caching: Smart Storage
CDNs store file copies. Updated your site? Clear the cache via Hostiserver’s API:

curl -X POST "https://api.hostiserver.com/v1/cache/purge" \
-H "Authorization: Bearer {your_api_key}" \
-H "Content-Type: application/json" \
--data '{"zone":"yourdomain.com","purge_all":true}'

Load Balancing
A CDN spreads traffic across servers. Imagine hosting a major sale—thousands of visitors come at once, yet your website remains stable and responsive. Smart algorithms redirect requests to available resources, ensuring stability during peak times.

Benefits of Using a CDN

• Speed: Latency decreases from 200 ms to 20 ms, giving your visitors faster load times.
• Stability: If one server (aka point of presence) goes down, the CDN technology will automatically send traffic to select the nearest healthy server.
• Resource Savings: After the CDN serves the static content for you, our main server is freed up to handle dynamic requests.
• SEO Boost: Sites that are faster help the Core Web Vitals, according to Google, and enhance search rankings.

For instance, implementing our CDN reduced load times for a client with 10,000 daily visitors from 4.8 to 1.2 seconds.

When Does Your Site Need a CDN?

How to Choose a CDN Provider?

• Coverage: A wider network of servers will lead to faster content delivery to more locations.
• Speed: Latency needs to be low—you can test it with trusted tools.
• Integration: Easy set up saves a lot of time and effort.
• Pricing: There are plans to meet any budget.
• Support: Fast technical support can really be a lifesaver in an unexpected emergency.

Hostiserver is a well-balanced tool with quality support with simple integration, but you have to decide what you're looking to achieve.

Provider Comparison

Technical Tips for Webmasters

Complex Configuration: For frequently updated sites:

location /news {
    proxy_cache off; # Disable caching for news
}
location /images {
    proxy_cache_valid 200 1y; # Cache images for a year
}

Apache Example: Using mod_cache:

    CacheEnable disk /images
    CacheDefaultExpire 31536000 # 1 year for static files

For SaaS: Use a CDN with WebSocket support for real-time chats or updates.

For Large Platforms: Distribute API requests via CDN with load balancing.

Tips for Complex Projects

CDN is just one piece of the puzzle for big systems. Here’s how to scale:

Docker: Containerization enables rapid site replication. For ecommerce during peak loads:

version: '3'
services:
  web:
    image: your-app:latest
    deploy:
      replicas: 5
    ports:
      - "80:80"

CDN handles traffic distribution, while Docker scales fast.

Kubernetes: Automate scaling with Horizontal Pod Autoscaler (HPA):

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: app-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: your-app
  minReplicas: 3
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 70

CDN offloads static content, allowing Kubernetes to efficiently manage dynamic loads. You can further enhance performance by combining CDN with edge computing, which processes requests even closer to users.

A CDN adds performance and reliability to your site - desirable if you have a global audience, an ecommerce site, or host media projects. However, if you're running a small local blog, a standard hosting plan is usually sufficient without a CDN. Hostiserver provides integrated CDN solutions.

Ready to speed things up? Contact our team or explore Hostiserver CDN offerings to find the best fit for your website.

FAQ