​I. What is CDN Acceleration?

from flask import Flask, request, Response
import requests
import hashlib
import os
app = Flask(__name__)
CACHE_DIR = "cdn_cache"  # Local cache directory
os.makedirs(CACHE_DIR, exist_ok=True)
ORIGIN_SERVER = "http://origin-server.com"  # Origin server address

def get_cache_path(url):
    """ Generate the cache file path """
    hashed_url = hashlib.md5(url.encode()).hexdigest()
    return os.path.join(CACHE_DIR, hashed_url)

@app.route("/cdn/", methods=["GET"])
def cdn_proxy(file_path):
    cache_path = get_cache_path(file_path)
    
    # If the cache exists, return the cache content directly
    if os.path.exists(cache_path):
        with open(cache_path, "rb") as f:
            return Response(f.read(), content_type="application/octet-stream")
    
    # Fetch the resource from the origin server
    origin_url = f"{ORIGIN_SERVER}/{file_path}"
    response = requests.get(origin_url)
    
    if response.status_code == 200:
        # Save to the cache
        with open(cache_path, "wb") as f:
            f.write(response.content)
        return Response(response.content, content_type=response.headers["Content-Type"])
    else:
        return Response("Not Found", status=404)

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)

II. The Working Principle of CDN Acceleration

; Example: CNAME Record Configuration in Route 53
example.com. 300 IN CNAME d123456abcdef.cloudfront.net.

from flask import Flask, request, jsonify
import random

app = Flask(__name__)
# Simulate a list of backend servers
backend_servers = [
    {"url": "http://backend1.local", "load": 10},
    {"url": "http://backend2.local", "load": 20},
    {"url": "http://backend3.local", "load": 5}
]

def select_server():
    """ Select the server with the lowest load """
    return min(backend_servers, key=lambda x: x["load"])

@app.route("/route", methods=["GET"])
def route_request():
    server = select_server()
    server["load"] += 1  # Simulate the increase in load due to the request
    return jsonify({"redirect_to": server["url"]})

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)

3，Caching Technology

server {
    listen       80;
    server_name  example.com;

    location / {
        proxy_pass http://origin_server;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        # Set the cache expiration time
        expires 1h;
    }
}

III. Core Technologies

• Caching Technology: By leveraging technologies such as proxy caching and transparent caching, static resources are stored on nodes closer to users, reducing repeated requests and data transfer times.
• Load Balancing Technology: This technology distributes user requests evenly among multiple edge servers to prevent a single node from being overloaded and to ensure high availability across the entire network.
• Intelligent Scheduling Algorithm: Based on factors like user geolocation, network conditions, and node load, this algorithm selects the best - performing node in real - time to provide services, enabling nearby access.
• Dynamic Content Delivery: In addition to static content, some CDNs also support accelerating certain dynamic content. This is accomplished by optimizing transport protocols (such as HTTP/3 and QUIC) to reduce latency.

IV. Advantages of CDN Acceleration

• Improved Access Speed: User requests can be directly responded to by nearby edge nodes, significantly reducing latency caused by long - distance transmission.
• Reduced Origin Server Load: Most user requests are directly answered from the edge node cache, alleviating the pressure on the origin server. This, in turn, reduces operating costs and bandwidth consumption.
• Enhanced Website Stability: When a node fails, the system can automatically switch to other nodes, ensuring continuous service availability.
• DDoS Resistance: The distributed architecture spreads traffic across multiple nodes, effectively mitigating the impact of large - scale attacks on a single server.
• Global Coverage and Elastic Scalability: Regardless of the user's location, they can enjoy nearby services. Additionally, CDN can dynamically expand service nodes according to traffic demands.

V. Application Scenarios

• Full - site Website Acceleration: Caches static resources and some dynamic content to improve web page loading speed.
• Video on Demand and Live Streaming: Distributes large - scale video streams to ensure smooth playback and a low - latency experience.
• Large - file Download: Rapidly distributes large - volume files such as software, games, or documents, reducing the bandwidth pressure on the origin server.
• Mobile Application Acceleration: Enables fast and stable data transmission for scenarios such as App data synchronization and image loading.

VI. Service Provider Recommendations and Price Comparison

1. cdn07
   • Features and Advantages:
     • Global License - free and High - security DDoS Protection: cdn07 focuses on license - free services in the Asia - Pacific region, T - level DDoS protection, and intelligent acceleration. It is especially suitable for enterprises with extremely high security requirements.
     • Flexible Billing: Offers a free trial plan (no credit card required) and has two billing models: pay - as - you - go and package - based billing, making it suitable for small and medium - sized enterprises as well as international projects.
     • Multilingual Localization Support: In addition to Chinese, it supports multilingual interfaces such as English and Japanese, facilitating use by global customers.

Price Comparison (Reference):

• Free Trial Plan: You can experience a certain amount of traffic for free each month (for example, a 100GB free quota according to the official website announcement).
• Examples of Paid Packages: The price range of standard, business, and enterprise packages generally starts from around $10 per month. The specific price depends on protection capabilities, traffic, and additional features such as SSL and WebSocket support.
  Official Website: https://www.cdn07.com/

2. Amazon CloudFront

• Features and Advantages:
  • Deep Integration with the AWS Ecosystem: Suitable for enterprises that have already deployed services on AWS, supporting seamless integration with S3, EC2, Elastic Load Balancing, etc.
  • Wide Global Coverage: With over 180 edge nodes, it can provide relatively stable acceleration services globally.
  • High Security: Equipped with strict security certifications and flexible access control policies.
• Price Comparison (Reference):
  Depending on the usage region, the price for the first 10TB of traffic ranges from $0.04 - $0.085 per GB. The price structure is relatively complex, making it suitable for medium - to - large - scale traffic projects.
  Official Website: https://aws.amazon.com/cloudfront/

3. Cloudflare

• Features and Advantages:
  • Advantages of the Free Tier: Cloudflare offers a free CDN service, which is suitable for personal websites with low traffic or startup enterprises.
  • Easy to Connect: After changing the NS, you can enjoy automatically issued SSL, intelligent routing, and protection functions.
  • Global Anycast Network: With numerous global nodes, it ensures excellent access speeds from overseas.
• Price Comparison (Reference):
  • The free version can meet basic needs.
  • The professional version is approximately $20 per month, and the enterprise version is about $200 per month, suitable for projects with high security and customization requirements.
    Official Website: https://www.cloudflare.com/

4. Fastly

• Features and Advantages:
  • High Performance and Flexibility: A premium CDN service for developers, supporting instant configuration updates and fine - grained cache control, suitable for accelerating high - demand Web and mobile applications.
  • Real - Time Logging and Monitoring: Helps with precise tuning and troubleshooting.
• Price Comparison (Reference):
  • North America/Europe Region: Approximately $0.12 per GB for the first 10TB (the price decreases for the excess amount).
  • The price structure varies greatly by region, making it suitable for enterprises with high traffic and a pursuit of high performance.
    Official Website: https://www.fastly.com/

5. KeyCDN

• Features and Advantages:
  • Cost - effective: KeyCDN's pay - as - you - go model is very flexible with a relatively low unit price, making it especially suitable for projects with limited budgets.
  • Simple Integration Method: It offers CNAME integration, a 30 - day free trial (about 25GB of traffic), and supports Let’s Encrypt independent SSL.
• Price Comparison (Reference):
  • North America/Europe Region: The price for the first 10TB can be as low as $0.04 per GB. The price in Asia/Oceania is slightly higher, but it remains competitive overall.
• Official Website: https://www.keycdn.com/

6. Microsoft Azure CDN

• Features and Advantages:
  • Deep Integration with Azure Cloud Services: For enterprises that have already built applications within the Azure ecosystem, Azure CDN is a great choice.
  • Global Coverage and Strong Back - end Support: It has wide - reaching coverage and relatively transparent pricing, making it suitable for international projects.
• Price Comparison (Reference):
  • Pricing varies depending on the operating region and traffic requirements. Generally, the price is at a mid - level among international mainstream CDN service providers. For specific details, refer to the official Azure pricing page.
• Official Website: https://azure.microsoft.com/en - us/products/cdn
   

7. Akamai

• Features and Advantages:
  • Globally Leading Network: Akamai has an extremely large edge - node network, suitable for ultra - large enterprises with extremely high requirements for stability and performance.
  • Advanced Security and Media Services: It provides adaptive media delivery, real - time analysis, and professional security protection.
• Price Comparison (Reference):
  • Akamai's pricing is usually a customized plan, suitable for large enterprises and multinational companies. The price is high, but it offers comprehensive services and excellent performance.
• Official Website: https://www.akamai.com/

Comprehensive Comparison

Selection and Implementation Recommendations

1，Service Provider Selection Criteria

• Node Coverage: The number of global nodes, the quality of carrier network lines (such as BGP multi - line).
• Protection Capability: DDoS scrubbing bandwidth, the update frequency of WAF rules.
• Data Monitoring: Provide tools for real - time traffic analysis, log auditing, etc.
• Service Response: 7×24 - hour technical support, SLA commitments (such as 99.99% availability).

2，Implementation Steps

• Content Classification: Differentiate between static and dynamic content and develop differential caching strategies.
• Origin - Pull Optimization: Configure intelligent origin - pull routing to reduce cross - carrier origin - pull latency.
• Monitoring and Tuning: Integrate with cloud monitoring platforms through APIs to adjust node loads in real - time.

VII. FQA