Latest 40 CDN Interview Questions

Introduction

Are you preparing for an interview in the field of Content Delivery Networks (CDNs)? CDNs are crucial in delivering web content efficiently and improving user experience. To help you succeed, here’s a quick introduction to CDN interview questions. Expect queries about CDN basics, such as its purpose and benefits. You may also encounter questions about CDN architecture, caching mechanisms, and load balancing techniques. Understanding CDN security, performance optimization, and troubleshooting will be essential. Moreover, be prepared to discuss popular CDN providers and their features. Remember to demonstrate your knowledge and passion for CDNs while answering these questions to impress your potential employers. Good luck with your interview preparation!

Questions

1. What is a CDN?

A CDN (Content Delivery Network) is a distributed network of servers strategically placed across various geographic locations to deliver web content efficiently to end-users. CDNs work by caching and delivering static content (such as images, videos, CSS, JavaScript files, etc.) closer to users, reducing the distance between the user’s device and the server, thereby improving website performance and load times.

Example: Let’s say you have a website with images hosted on a server in the United States. Without a CDN, users from other countries would experience slower load times due to the distance between their location and the server. With a CDN, copies of those images are cached on servers located in multiple regions worldwide. When a user accesses your website, they get served the image from the closest CDN server, resulting in faster loading times.

2. How does a CDN work?

CDNs work by employing a network of geographically distributed edge servers. The process of how a CDN works can be summarized as follows:

1. Content Replication: The CDN provider caches and stores copies of your website’s static content on its edge servers located in various geographic locations.
2. DNS Resolution: When a user tries to access your website, their DNS request is routed to the nearest DNS server of the CDN.
3. Edge Server Selection: The CDN’s DNS server selects the most suitable edge server based on the user’s location and other factors (e.g., server load, latency).
4. Content Delivery: The selected edge server delivers the requested content to the user’s device from its cache, reducing the load on the origin server and improving performance.
5. Cache Management: CDNs employ various cache eviction policies to ensure they serve fresh content while still benefiting from caching.

3. What are the benefits of using a CDN?

Using a CDN offers several benefits:

• Improved Website Performance: Content is delivered from the nearest edge server, reducing latency and improving load times.
• High Availability: CDNs replicate content, providing redundancy and ensuring your website remains accessible even if the origin server goes down.
• Reduced Server Load: Offloading traffic to CDN edge servers reduces the load on the origin server, improving its performance and scalability.
• Global Reach: CDNs have servers in multiple regions, allowing your content to be accessible worldwide with minimal latency.
• Bandwidth Savings: CDNs optimize content delivery, reducing the bandwidth consumption of the origin server.
• Improved User Experience: Faster load times and reduced latency lead to a better overall user experience.

4. What types of content can be served by a CDN?

CDNs can serve various types of content, including:

• Static Content: This includes images, videos, CSS files, JavaScript files, fonts, and other assets that do not change frequently.
• Dynamic Content: Though CDNs are primarily designed for static content, some CDNs can cache and deliver dynamic content too. This includes content generated by server-side scripts like PHP or data fetched from APIs.
• Streaming Media: CDNs are widely used for video and audio streaming, providing smooth and buffer-free playback.
• Large File Downloads: CDNs can efficiently handle the delivery of large files like software installers, game updates, etc.
• Web Pages: CDNs can also cache entire web pages and deliver them to users.

5. What is the difference between push and pull CDNs? (in tabular form)

6. What are cache eviction policies in CDNs? (in points)

Cache eviction policies determine how long content should be cached on CDN edge servers before it is purged and refreshed from the origin server. Common cache eviction policies include:

• Time-based Expiration: Content is cached for a specific time duration, after which it is considered stale and fetched from the origin server again.
• LRU (Least Recently Used): When the cache reaches its limit, the least recently accessed content is evicted to make room for new content.
• LFU (Least Frequently Used): Content with the lowest access frequency is evicted from the cache.
• MRU (Most Recently Used): The most recently accessed content is evicted first when the cache is full.
• Random Replacement: Content is evicted randomly when the cache reaches its limit.

7. How can you ensure cache freshness in a CDN?

To ensure cache freshness in a CDN, you can use cache control headers to specify how long the content should be cached before it is considered stale. Two common cache control headers are:

• Cache-Control: This header allows you to set various caching directives, including “max-age” to specify the time duration for which the content is considered fresh.
• Expires: This header indicates an absolute expiration time for the content, after which it should be revalidated with the origin server.

Example (in C++) – Setting Cache-Control header for a static file:

#include <iostream>
#include <string>

int main() {
    std::string staticFileContent = "Your static file content here...";
    // Assuming you are serving this file via a web server, add the Cache-Control header:
    std::cout << "Content-Type: text/plain" << std::endl;
    std::cout << "Cache-Control: max-age=3600" << std::endl; // Cache for one hour
    std::cout << std::endl;
    std::cout << staticFileContent;
    return 0;
}

8. How can you measure the performance of a CDN?

The performance of a CDN can be measured using various metrics, including:

• Latency: The time it takes for a user’s request to reach the CDN edge server.
• Load Time: The time it takes for a web page or content to load completely in the user’s browser.
• Cache Hit Ratio: The percentage of requests that are served from the CDN cache without fetching from the origin server.
• Throughput: The rate at which data is transferred between the CDN and the user.
• Error Rate: The percentage of requests that result in errors or failures.
• Geographic Distribution: The coverage of the CDN’s edge servers across different regions.

9. What security measures can be implemented in a CDN?

CDNs can implement various security measures to protect against threats such as DDoS attacks, data breaches, and unauthorized access. Some common security

measures include:

• Web Application Firewall (WAF): WAF filters and blocks malicious traffic before it reaches the origin server.
• DDoS Mitigation: CDNs can use DDoS protection techniques to detect and mitigate large-scale attacks.
• SSL/TLS Encryption: CDNs can provide SSL/TLS certificates to enable secure encrypted communication between the user and the CDN server.
• Access Control: CDNs can restrict access to certain content based on user authentication or IP whitelisting.
• Bot Protection: CDNs can identify and block malicious bots to prevent scraping and abuse.
• Origin Shielding: Adding an extra layer (origin shield) between the CDN and the origin server to further protect it from direct access.

10. How does a CDN handle dynamic or personalized content?

CDNs are primarily designed for caching and delivering static content. However, some CDNs offer solutions for handling dynamic or personalized content. One common approach is to use Edge Side Includes (ESI) or similar technologies.

ESI allows you to cache parts of a web page while dynamically fetching personalized content from the origin server. The static parts of the page are cached on the CDN, while the dynamic parts are fetched and assembled at the edge servers.

Example (in C++) – Using Edge Side Includes (ESI):

#include <iostream>
#include <string>

// Function to fetch personalized content from the origin server
std::string fetchDynamicContentFromOrigin(int userId) {
    // Code to fetch dynamic content for the given user ID from the origin server
    return "Dynamic content for user " + std::to_string(userId);
}

int main() {
    int userId = 12345;
    // Assuming you have a CDN serving this page with ESI support:
    std::cout << "Content-Type: text/html" << std::endl;
    std::cout << std::endl;
    std::cout << "<html><head><title>Personalized Page</title></head><body>" << std::endl;
    // Cached static content:
    std::cout << "<h1>Welcome to the CDN</h1>" << std::endl;
    // ESI tag to fetch dynamic content:
    std::cout << "<esi:include src=\"/dynamic-content?user=" << userId << "\" />" << std::endl;
    std::cout << "</body></html>" << std::endl;
    return 0;
}

In this example, the CDN caches the static HTML content, and the dynamic content is fetched from the origin server using ESI.

11. What are the popular CDN providers in the market?

Some popular CDN providers in the market include:

• Cloudflare
• Akamai
• Amazon CloudFront
• Microsoft Azure CDN
• Fastly
• StackPath
• KeyCDN
• Verizon Media Platform (formerly Verizon Digital Media Services)
• Limelight Networks

12. What factors should be considered when selecting a CDN provider?

When selecting a CDN provider, consider the following factors:

• Geographic Coverage: The number and distribution of edge servers around the world.
• Performance: Latency, load times, and cache efficiency.
• Scalability: Ability to handle traffic spikes and growing demand.
• Security: DDoS protection, SSL/TLS support, and other security features.
• Pricing: Cost structure, overage charges, and additional features.
• Support: Availability of technical support and documentation.
• Reliability: Uptime and SLAs (Service Level Agreements).
• Integration: Compatibility with your existing infrastructure and applications.
• Analytics and Reporting: Insights into CDN performance and usage.

13. What is the role of DNS in a CDN?

The DNS (Domain Name System) plays a crucial role in a CDN. When a user enters a URL in their web browser, the DNS is responsible for translating the human-readable domain name into the IP address of the closest CDN edge server. This process is known as DNS resolution. By directing users to the nearest edge server, the DNS helps reduce latency and improve the performance of content delivery.

14. How can you invalidate or purge content from a CDN’s cache?

To invalidate or purge content from a CDN’s cache, you typically need to send a request to the CDN with specific cache invalidation instructions. Many CDNs provide APIs or control panels for managing cache purging. You can use the URL of the content you want to invalidate or purge, or use wildcard patterns to invalidate multiple files.

Example (in C++) – Using a hypothetical CDN API for cache invalidation:

#include <iostream>
#include <string>

void invalidateCDNCache(const std::string& url) {
    // Code to send a request to the CDN API for cache invalidation.
    // The API call could be something like:
    // cdnProvider.invalidateCache(url);
}

int main() {
    std::string contentUrl = "https://www.example.com/images/example.jpg";
    invalidateCDNCache(contentUrl);
    return 0;
}

15. How can you ensure the consistency of content across a CDN?

To ensure content consistency across a CDN, follow these best practices:

• Use a versioning or fingerprinting mechanism for static files to prevent serving outdated content.
• Set proper cache control headers to control the caching behavior and expiration of content.
• Implement cache purging or invalidation mechanisms when content is updated on the origin server.
• Regularly monitor CDN behavior and cache hit ratios to identify any discrepancies.

16. What challenges can arise when using a CDN?

Using a CDN can introduce some challenges, such as:

• Cache Invalidation: Ensuring that updated content is immediately reflected across the CDN.
• Dynamic Content: Handling personalized or dynamically generated content effectively.
• Security: Ensuring proper security measures to protect against potential threats.
• Cost: Managing costs, especially for large-scale websites with high traffic.
• Integration: Integrating the CDN with existing infrastructure and applications.
• Consistency: Ensuring content consistency across the CDN and origin server.

17. How can you determine if a CDN is providing the expected performance improvement?

To determine if a CDN is providing the expected performance improvement, you can:

• Measure and compare the load times and latency with and without the CDN.
• Analyze cache hit ratios to see how often content is served from the CDN cache.
• Monitor network performance and server response times for CDN requests.
• Conduct real-world tests with users from different locations and analyze their experiences.
• Use performance monitoring tools and CDN analytics to gain insights.

18. What is the difference between a CDN and a web server?

19. Can a CDN handle dynamic or real-time data?

While CDNs are primarily designed for caching and delivering static content, some CDNs offer solutions for handling dynamic or real-time data. Edge Side Includes (ESI) and other technologies can help fetch personalized content from the origin server while caching the static parts of a web page.

20. How does a CDN handle SSL/TLS encryption?

CDNs can handle SSL/TLS encryption by providing SSL/TLS certificates and enabling secure communication between users and the CDN edge servers. When a user accesses a website over HTTPS, the SSL/TLS handshake is established between the user’s device and the CDN server, ensuring encrypted data transmission.

21. Can a CDN be used for video streaming?

Yes, CDNs are widely used for video streaming. CDN edge servers cache and deliver video content to users, reducing buffering and improving the overall streaming experience. Popular video streaming services often leverage CDNs to deliver their content globally.

22. How does a CDN handle caching when the origin server sets cache control headers?

When the origin server sets cache control headers, the CDN follows the specified caching directives. For example, if the origin server sets a “max-age” value of one hour, the CDN will cache the content for one hour before checking for updates. If the content has not expired, the CDN serves it from the cache; otherwise, it fetches the updated content from the origin server.

23. What is the role of edge locations in a CDN?

Edge locations are data centers or servers strategically located in various geographic regions. Their role in a CDN is to cache and serve content to end-users from nearby locations, reducing latency and improving content delivery performance. These edge locations act as intermediate points between the origin server and the end-users.

24. How does a CDN handle client-side cache control?

CDNs can handle client-side cache control through cache control headers, such as “max-age” and “Cache-Control: private.” These headers instruct the user’s browser on how long to cache the content locally. The browser then uses the cached content for subsequent requests without contacting the CDN until the specified expiration time.

25. What is the role of DNS-based load balancing in a CDN?

DNS-based load balancing in a CDN involves using DNS to direct users to the most suitable edge server based on factors such as their location, server load, and network conditions. This helps distribute user requests across multiple servers, optimizing resource usage and improving performance.

26. How does a CDN handle HTTPS requests?

CDNs handle HTTPS requests by acting as a middle layer between the client and the origin server. When a client makes an HTTPS request to the CDN, the CDN terminates the SSL/TLS connection on its edge servers. It then establishes a separate SSL/TLS connection with the origin server to fetch the requested content. The CDN encrypts the content again with its SSL/TLS certificate before delivering it securely to the client.

Here’s an example of how a CDN might handle an HTTPS request using a Python-based CDN edge server:

# Assuming the CDN edge server receives an HTTPS request
def handle_https_request(request):
    # Terminate the client's SSL/TLS connection
    decrypted_request = decrypt_ssl_request(request)

    # Determine the content to fetch from the origin server
    requested_content = get_requested_content(decrypted_request)

    # Establish a separate SSL/TLS connection with the origin server
    origin_server_response = establish_ssl_connection_with_origin(requested_content)

    # Encrypt the response with CDN's SSL/TLS certificate
    encrypted_response = encrypt_ssl_response(origin_server_response)

    # Send the encrypted response back to the client
    return encrypted_response

27. Can a CDN help mitigate distributed denial-of-service (DDoS) attacks?

Yes, CDNs can help mitigate DDoS attacks by distributing and absorbing the attack traffic across their globally distributed edge servers. When a DDoS attack is launched against a website, the CDN’s edge servers act as a buffer, filtering out malicious traffic and allowing only legitimate requests to reach the origin server. By doing so, the CDN prevents the origin server from being overwhelmed and ensures the website remains accessible to legitimate users.

CDNs can use various techniques like rate limiting, IP filtering, and challenge-response tests to identify and block malicious traffic. Here’s a simplified example of how a CDN might handle DDoS protection:

def handle_ddos_attack(request):
    if is_legitimate_request(request):
        # Allow legitimate traffic to pass through to the origin server
        return forward_to_origin(request)
    else:
        # Block malicious traffic at the edge server level
        return block_request(request)

28. How can a CDN improve website scalability?

CDNs can improve website scalability by distributing content across multiple geographically dispersed edge servers. When users request content, the CDN serves it from the nearest edge server, reducing the load on the origin server and minimizing latency. This distribution of content ensures that the website can handle a large number of concurrent users without becoming overwhelmed.

Additionally, CDNs often use caching mechanisms to store frequently accessed content at the edge servers. Caching reduces the need to fetch content from the origin server for every request, further improving the website’s scalability and response times.

29. How does a CDN handle content updates or changes?

When content is updated or changed on the origin server, the CDN needs to ensure that the changes propagate to all its edge servers. This process is known as cache invalidation. CDNs use various cache invalidation techniques to ensure that stale content is purged from their edge servers, and fresh content is fetched from the origin server when necessary.

One common technique is the use of cache expiration headers, such as “Cache-Control” and “Expires,” which specify how long the content should be considered valid. When the expiration time is reached, the CDN fetches the updated content from the origin server.

Here’s an example of cache invalidation using HTTP cache headers:

# Origin server response with cache headers
def get_origin_server_response(request):
    if is_content_updated(request):
        # Update cache expiration headers
        response_headers = {
            "Cache-Control": "max-age=3600",  # Cache content for 1 hour
            "Expires": "Mon, 01 Jan 2024 00:00:00 GMT"
        }
        updated_content = fetch_updated_content()
        return (updated_content, response_headers)
    else:
        # Serve cached content from the CDN edge server
        return serve_cached_content()

30. Can a CDN be used for delivering APIs?

Yes, CDNs can be used for delivering APIs. CDNs are not limited to delivering static content; they can also cache and accelerate API responses. By caching API responses at the edge servers, CDNs can reduce the load on the origin server and improve the API’s performance and response times for users located far from the origin.

However, it’s essential to carefully consider caching strategies for APIs, as some API responses may be dynamic and not suitable for caching. Cache control headers and proper cache purging mechanisms should be implemented to ensure that only appropriate API responses are cached and served by the CDN.

31. How does a CDN handle cache coherency?

Cache coherency is the process by which CDNs ensure that the content served from their edge servers is consistent with the content on the origin server. When content is updated on the origin server, the CDN needs to invalidate or update the cached content on its edge servers.

CDNs use cache invalidation mechanisms, such as cache expiration headers or cache tags, to manage cache coherency. Cache tags are unique identifiers associated with cached content, allowing the CDN to selectively invalidate or purge specific content items.

Here’s a simplified example of using cache tags for cache coherency:

# Origin server response with cache tags
def get_origin_server_response(request):
    content, cache_tags = fetch_content_with_tags()
    return content, cache_tags

# CDN edge server handling request with cache tags
def handle_cdn_request(request):
    cached_content, cache_tags = get_cached_content_with_tags(request)
    if cache_tags_match_origin(cache_tags):
        # Serve cached content since it's still valid
        return cached_content
    else:
        # Fetch updated content from the origin server and update cache
        updated_content = fetch_updated_content()
        update_cache(request, updated_content)
        return updated_content

32. Can a CDN help in reducing server costs?

Yes, CDNs can help in reducing server costs for the website owner. By offloading a significant portion of the content delivery to the CDN’s edge servers, the origin server’s load is reduced, allowing it to handle fewer requests. This can lead to cost savings, as the origin server requires fewer resources and can be provisioned with lower capacity.

Furthermore, CDNs often offer various pricing plans based on the amount of data transferred or the number of requests made to their edge servers. By caching and serving content from the CDN, the amount of data transferred from the origin server decreases, potentially lowering data transfer costs.

33. How does a CDN handle failover and high availability?

CDNs ensure failover and high availability by deploying multiple redundant edge servers across different geographic locations. If one edge server becomes unavailable or experiences issues, the CDN automatically routes traffic to the nearest available edge server that can serve the requested content.

Additionally, CDNs monitor the health and performance of their edge servers and continuously update their routing tables to ensure efficient and reliable content delivery. This approach helps maintain high availability and ensures that users can access the content without interruptions, even if certain edge servers are experiencing problems.

34. Can a CDN improve SEO (Search Engine Optimization)?

Yes, a CDN can improve SEO by enhancing the website’s performance and user experience. Search engines consider page load times as one of the factors in their ranking algorithms. CDNs can significantly reduce page load times by caching and serving content from the nearest edge server to the user, resulting in better SEO rankings.

Additionally, CDNs help reduce server response times and lower the risk of slow-loading pages, which can contribute to better user engagement and lower bounce rates. As a result, CDNs indirectly impact SEO by providing a faster, more reliable website experience for users.

35. What is the role of origin shielding in a CDN?

Origin shielding, also known as origin cloaking, is a technique used by CDNs to add an extra layer of protection for the origin server. The purpose of origin shielding is to hide the actual origin server’s IP address from external requests, making it less susceptible to direct attacks or exposure.

Instead of directly connecting to the origin server, external requests are routed through an additional layer of servers known as the shield or shield nodes. The shield nodes act as intermediaries, forwarding requests to the origin server and caching responses, if necessary. This way, the actual IP address of the origin server remains hidden, providing an added security measure against potential attacks.

36. How does a CDN handle traffic routing?

CDNs use various algorithms and strategies to handle traffic routing efficiently. The goal is to direct user requests to the most appropriate edge server based on factors such as geographical proximity, server load, and network conditions.

Some common traffic routing algorithms used by CDNs include:

• Geo-based routing: Directing traffic to the nearest edge server based on the user’s geographical location.
• Anycast routing: Using the Border Gateway Protocol (BGP) to route traffic to the nearest available edge server in terms of network hops.
• Dynamic DNS-based routing: Using dynamic DNS updates to direct traffic based on real-time server availability and performance.

37. Can a CDN provide analytics and reporting?

Yes, CDNs can provide analytics and reporting on various aspects of content delivery and website performance. CDNs typically offer dashboards and analytics tools that provide insights into metrics such as:

• Traffic volume: The number of requests served by the CDN’s edge servers.
• Geographic distribution: The geographical locations of users accessing the content.
• Cache hit rate: The percentage of requests served from the CDN’s cache instead of the origin server.
• Performance metrics: Load times, latency, and response times for content delivery.

38. How does a CDN handle large file delivery?

CDNs are designed to efficiently handle large file delivery. When a large file is requested, the CDN splits the file into smaller chunks and distributes them across multiple edge servers. When the client requests the file, the CDN delivers the file chunks in parallel from multiple edge servers, reducing the overall download time.

Additionally, CDNs often use adaptive bitrate streaming techniques for large media files like videos. This approach adjusts the quality of the video stream based on the user’s network conditions, ensuring smooth playback and minimizing buffering.

39. Can a CDN help in reducing network congestion?

Yes, CDNs can help in reducing network congestion by caching and serving content from edge servers located closer to the end-users. By delivering content from nearby edge servers, CDNs reduce the amount of data that needs to traverse through the internet backbone, minimizing network congestion and potential bottlenecks.

Moreover, CDNs also use techniques like content compression and optimizing TCP connections to further reduce the data transmitted over the network, contributing to lower network congestion and improved overall network performance.

40. How can a CDN handle geolocation-based content delivery?

CDNs handle geolocation-based content delivery by leveraging information about the user’s IP address to determine their geographical location. When a user makes a request, the CDN examines the user’s IP address and maps it to a specific geographical region.

The CDN then routes the request to the edge server that is nearest to the user’s location, ensuring minimal latency and faster content delivery. This approach is particularly beneficial for delivering content like images, videos, or large files, where reducing latency is crucial for a better user experience.

To handle geolocation-based content delivery, CDNs maintain databases of IP address ranges and their corresponding geographical locations. They use this information to efficiently route traffic to the appropriate edge server.

MCQ Questions

1. What does CDN stand for?

a) Content Delivery Network
b) Central Data Network
c) Common Domain Name
d) Customer Development Network

Answer: a) Content Delivery Network

2. What is the main purpose of a CDN?

a) To improve website security
b) To reduce server response time
c) To distribute content to users more efficiently
d) To manage domain name registrations

Answer: c) To distribute content to users more efficiently

3. How does a CDN improve website performance?

a) By increasing server capacity
b) By optimizing website code
c) By caching content closer to users
d) By compressing images and files

Answer: c) By caching content closer to users

4. What is the benefit of caching content on edge servers in a CDN?

a) Faster content delivery to users
b) Improved website security
c) Reduced server load
d) Enhanced search engine optimization (SEO)

Answer: a) Faster content delivery to users

5. Which of the following is not a type of CDN server?

a) Origin server
b) Edge server
c) Proxy server
d) Load balancer

Answer: d) Load balancer

6. True or False: CDNs are only beneficial for large-scale websites with high traffic.

Answer: False

7. What is the process called when a CDN server requests content from the origin server?

a) Caching
b) Purging
c) Replication
d) Pulling

Answer: d) Pulling

8. Which HTTP header can be used to control caching behavior in a CDN?

a) Cache-Control
b) Content-Encoding
c) Content-Length
d) Last-Modified

Answer: a) Cache-Control

9. What is a POP in the context of a CDN?

a) Point of Presence
b) Proxy Origin Point
c) Packet Optimization Protocol
d) Performance Optimization Platform

Answer: a) Point of Presence

10. Which of the following is not a well-known CDN provider?

a) Cloudflare
b) Amazon Web Services (AWS)
c) Microsoft Office 365
d) Akamai Technologies

Answer: c) Microsoft Office 365

11. True or False: CDNs can help mitigate Distributed Denial of Service (DDoS) attacks.

Answer: True

12. What is the term used to describe the process of removing content from the cache of CDN servers?

a) Caching
b) Purging
c) Replication
d) Flushing

Answer: b) Purging

13. Which protocol is commonly used for content delivery in a CDN?

a) HTTP
b) FTP
c) SMTP
d) DNS

Answer: a) HTTP

14. Which of the following is not a benefit of using a CDN?

a) Improved website availability
b) Enhanced website security
c) Reduced bandwidth costs
d) Increased server response time

Answer: d) Increased server response time

15. What is the term used to describe the process of distributing content to CDN servers?

a) Caching
b) Purging
c) Replication
d) Seeding

Answer: c) Replication

16. True or False: CDNs can improve website rankings in search engine results .

Answer: True

17. Which of the following is not a factor to consider when choosing a CDN provider?

a) Geographic coverage
b) Network performance
c) Server operating system
d) Pricing and cost

Answer: c) Server operating system

18. What is the purpose of DNS-based load balancing in a CDN?

a) To distribute traffic evenly across multiple CDN servers
b) To cache DNS records for faster lookup
c) To manage domain name registrations
d) To protect against DDoS attacks

Answer: a) To distribute traffic evenly across multiple CDN servers

19. True or False: CDNs can only cache static content like images and CSS files.

Answer: False

20. Which of the following is not a commonly used CDN caching strategy?

a) Time-based expiration
b) Content-based expiration
c) Location-based expiration
d) Size-based expiration

Answer: c) Location-based expiration

21. What is the primary benefit of using a CDN for streaming media content?

a) Reduced buffering and improved playback experience
b) Increased video resolution and quality
c) Enhanced content security and DRM support
d) Lower bandwidth usage

Answer: a) Reduced buffering and improved playback experience

22. What is the term used to describe the process of loading content into the cache of CDN servers?

a) Caching
b) Purging
c) Seeding
d) Replication

Answer: c) Seeding

23. True or False: CDNs can provide detailed analytics and insights about content delivery performance.

Answer: True

24. Which of the following is a popular open-source CDN software?

a) Cloudflare
b) Akamai Technologies
c) Fastly
d) Varnish Cache

Answer: d) Varnish Cache

25. What is the term used to describe the process of redirecting user requests to the nearest CDN server?

a) Routing
b) Load balancing
c) Geo-routing
d) Anycast

Answer: c) Geo-routing

26. True or False: CDNs can automatically adapt content delivery based on user device and network conditions.

Answer: True

27. Which of the following is not a CDN performance metric?

a) Time to First Byte (TTFB)
b) Page load time
c) Time to Last Byte (TTLB)
d) DNS lookup time

Answer: c) Time to Last Byte (TTLB)

28. What is the term used to describe the process of distributing traffic across multiple CDN servers?

a) Caching
b) Purging
c) Load balancing
d) Replication

Answer: c) Load balancing

29. True or False: CDNs can provide SSL/TLS encryption for secure content delivery.

Answer: True

30. Which of the following is not a common CDN pricing model?

a) Pay-as-you-go
b) Flat monthly fee
c) Bandwidth-based pricing
d) Time-based expiration

Answer: d) Time-based expiration