16 Most Popular CDN Interview Questions and Answers (2024)

Blog / 16 Most Popular CDN Interview Questions and Answers (2024)

A CDN (Content Delivery Network) is a system of distributed servers that delivers web content, such as web pages, videos, images, and other types of web assets, to users based on their geographic location.

CDNs are becoming a bigger and bigger part of distributed computing and something all developers need to know the fundamentals about.

This blog will teach you the most up to date CDN interview questions and will help you nail your next interview.

Q1.

What is a CDN?

Junior

A Content Delivery Network (CDN) is a system of distributed servers that delivers web content, such as web pages, videos, images, and other types of web assets, to users based on their geographic location, the origin of the webpage, and a content delivery server.
The primary goal of a CDN is to improve access to web content by reducing latency, which is the time taken for a web page or file to be delivered to a user's device.

Q2.

Name some advantages of a CDN.

Junior

Faster Load Times: Reduces website and content loading time.
Reduced Bandwidth Costs: Decreases data load on the origin server, cutting bandwidth expenses.
High Availability and Redundancy: Ensures content availability even during high traffic or server failures.
Enhanced User Experience: Improves overall responsiveness and user interaction.
Scalability: Effectively handles traffic spikes and large-scale content delivery.
Improved Security: Offers features like DDoS protection and SSL/TLS encryption.
Global Reach: Delivers content efficiently worldwide, minimizing geographic latency.
Load Balancing: Distributes traffic evenly across servers, preventing overload.
SEO Benefits: Faster sites potentially achieve better search engine rankings.
Lower Server Load: Eases the burden on the origin server, enhancing performance and reducing maintenance needs.

Q3.

Briefly explain how a CDN works.

Junior

A Content Delivery Network (CDN) enhances the speed and efficiency of content delivery over the internet. It works by:
- Distributing Servers Globally: Placing multiple servers at different geographic locations.
- Redirecting User Requests: When a user requests content (like a web page or image), the request is redirected to the nearest server.
- Delivering Cached Content: The closest server responds with the cached content, reducing the data delivery time.
- Fetching and Storing New Content: If the content isn't on the nearest server, it's retrieved from the origin server and cached for future requests.

Preparing for a tech interview?👉Top 23 CDN questions

Q4.

Name some applications of a CDN.

Junior

Web Content Delivery: Speeding up the loading of web pages by caching HTML files, stylesheets, JavaScript, and images.
Video Streaming: Reducing buffering and improving the quality of video streaming services.
Software Distribution: Facilitating faster downloads of software, updates, and patches.
E-commerce Platforms: Enhancing the performance and user experience of online shopping sites, especially during high traffic periods.
Online Gaming: Reducing latency and improving the speed of game content delivery for a better gaming experience.
Media and Advertising: Efficient delivery of media content and advertisements to various geographical locations.

Q5.

How does caching work in a CDN.

Mid

Initial Content Fetch: Content is initially retrieved from the origin server upon the first request.
Caching on Edge Servers: This content is cached on CDN's edge servers, located closer to users.
Serving Cached Content: Subsequent user requests are fulfilled from the nearest edge server's cache, reducing load times.
Time-to-Live (TTL): Cached content has a set TTL, determining how long it's stored before being refreshed from the origin server.
Cache Invalidation: Content can be manually removed or updated in the cache as needed.
Optimization: The CDN may optimize content for faster delivery, like compressing files.

Don't let one question ruin your next technical interview...

Caching•13

Microservices•37

Q6.

What does TTL mean?

Mid

TTL, or "Time to Live," is a setting that determines how long a piece of information remains valid or stored. In networking, it refers to the lifespan of data packets, decreasing with each hop in the network until they are discarded. In DNS systems, it dictates how long DNS records are cached before a fresh query is made.
In caching systems, like CDNs, it specifies how long content stays in the cache before being refreshed or removed. Essentially, TTL helps balance data freshness with resource usage.

Q7.

What does cache hit ratio mean?

Mid

Cache hit ratio in computing refers to the percentage of requested data that is served from the cache, rather than directly from the original data source. It's a measure of the effectiveness of the cache system.
Higher ratios indicate more efficient caching, leading to faster data retrieval and reduced load on the primary data source.

Q8.

What is cache invalidation?

Mid

Cache invalidation is the process of removing or marking as outdated the cached data. This is necessary when the original data has changed, ensuring that users don't receive stale or incorrect information. Invalidation can be challenging in distributed systems, as it must ensure that all cache locations are updated or cleared simultaneously.

Q9.

What are edge servers?

Mid

Edge servers are computing nodes located close to the end-users, designed to deliver content and services with reduced latency and improved performance by processing data closer to where it is generated or consumed.
They are commonly used in distributed networks and content delivery systems.

Q10.

Name some popular CDN providers

Mid

Akamai Technologies: Extensive network, advanced security services.
Cloudflare: User-friendly, integrated security services, strong web security focus.
Amazon CloudFront: Seamless integration with AWS services.
Fastly: High-performance edge computing, real-time updates, streaming support.
KeyCDN: Cost-effective, pay-as-you-go pricing, suits small to medium businesses.
MaxCDN (StackPath): Ease of use, comprehensive web services suite.
CDN77: Transparent pricing, strong data security, high bandwidth.
Microsoft Azure CDN: Integration with Azure services, tailored for Microsoft applications.
Google Cloud CDN: Integration with Google Cloud, advanced analytics, machine learning features.
Limelight Networks: Specializes in video and media content delivery, robust content management tools.

Q11.

How do you measure the performance of a CDN?

Mid

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem.

Q12.

How does DNS play a role in CDN functionality?

Senior

Q13.

Describe the architecture of a typical CDN.

Senior

Q14.

Discuss common security practices in CDN operations.

Senior

Q15.

How does a CDN contribute to web optimization techniques like minification, compression, and image optimization?

Senior

Q16.

Describe how a CDN can manage a sudden increases in traffic

Senior