Many people first learn about CDN when their website becomes unbearably slow. Pages take forever to load, images keep spinning, and users close the tab before even seeing the content.

So you search for solutions, and almost every answer points to one thing: CDN Acceleration.

But reality often hits like this------
👉 You spend the money, you set up the CDN, but your website is still slow.

Is the CDN really the problem? Or did we misunderstand what CDN actually does from the very beginning?

1. What is CDN? What is CDN Acceleration?

CDN, short for Content Delivery Network.

Put simply:

It stores your website's content on servers closer to your users in advance.

Before CDNs, all users accessed your single origin server. If the server was in Beijing, users in Guangdong had slow access; if it was overseas, mainland access was even slower.

Here's how a CDN works:

• It caches content like images, JS, CSS, videos, etc.
• On "edge nodes" located all across the country/region.
• When a user visits, the request is served from the nearest available node.

That's what we call CDN Acceleration.

Note a key phrase: 👉 "Nearest".

If this "nearness" itself is problematic, acceleration becomes an empty promise.

2. Why Do Many People Experience "Slow Websites Even With a CDN"?

This is the most common complaint I've seen, hands down.

It usually boils down to these reasons:

1️⃣ The Node is "Geographically Close" but "Network-Far"

Many CDNs advertise hundreds of nodes. But you need to know:

• Mainland China has three major telecom operator systems.
• Quality varies massively between different provinces and network lines.
• Some nodes "appear to be in your province" but traffic takes a serious detour.

The result?
👉 Theoretically nearby, practically slower.

2️⃣ The CDN Only Accelerates Static Resources, Dynamic Requests Are Still Slow Going Back to Origin

This is where most people get tripped up.

Many users think:

"My whole website will be faster once I use a CDN."

But in reality, most CDNs only cache these by default:

• Images
• JS / CSS
• Video chunks

While your:

• Login APIs
• API requests
• Dynamic pages

Still have to travel back to the origin server.

If your origin server is overseas or has poor connectivity,
👉 The CDN only solves half the problem.

3️⃣ During an Attack, the CDN Itself Becomes the Bottleneck

This is an even more real issue.

Many traditional CDNs are essentially just "content distributors," not "protection systems."
Once they face:

• CC attacks
• Low-volume, high-frequency requests
• Malicious bots

The result is:

Nodes get slowed down, the origin gets overwhelmed, and acceleration fails completely.

This is why many site owners reach a turning point: 👉 "Turns out I don't need a faster CDN, I need a more robust one."

3. The "Limits" of Mainland China CDNs You Must Know in Advance

Let's be honest:

A Mainland China CDN is not a magic bullet.

It has inherent limitations you can't avoid.

① ICP Filing & Compliance are Prerequisites

Almost all formal Mainland China CDNs require:

• Domain ICP filing
• Real-name verification
• Compliant business type

If your business isn't suitable for filing, 👉 forcing a Mainland CDN is the wrong choice from the start.

② Mainland CDNs are Strong, but "They Only Cover Mainland China"

A common mistake is: 👉 Using a Mainland CDN to solve overseas access issues.

The results, of course, are poor.

The strength of a Mainland CDN lies in:

• Coverage across the three domestic networks
• Low latency
• High stability

But it's often not the optimal solution for overseas access.

③ Protection Capabilities Vary Wildly

This is a fact many "top lists" shy away from.

• Some CDNs offer protection as an "add-on"
• Some are built on high-defense architectures from the ground up
• Some throttle or even suspend your domain the moment an attack hits

Before you choose, be crystal clear: Do you just want speed, or do you want "speed plus resilience"?

4. Choosing a Mainland China CDN: What to Look For Beyond Speed?

If you only focus on "speed," you'll likely choose wrong.

A truly reliable selection should consider at least these 5 points:

1️⃣ Tri-carrier (China Telecom / Unicom / Mobile) Routing Capability
2️⃣ Are Nodes Truly Usable, or Just Marketing Numbers?
3️⃣ Quality of the Back-to-Origin Network Lines
4️⃣ Support for Dynamic Acceleration / TCP / QUIC, etc.
5️⃣ Can It Maintain Access During an Attack?

In short:

Speed isn't the key; consistent speed is.

5. With That in Mind, Let's Look at: The Mainland China CDN Acceleration Top 5 Provider Ranking

This ranking isn't about "who's the most famous," but who is more suitable for different types of users in real-world scenarios.

🥇 Alibaba Cloud CDN

Best for: Standardized enterprises, compliance-focused projects, high-traffic businesses

Alibaba Cloud CDN's advantages are clear: extensive node coverage, mature tri-carrier routing, strong stability. For corporate sites, e-commerce platforms, long-term projects, it's almost the "safe, no-mistake choice."

The downsides are also evident: pricing isn't low, configuration is complex, not very beginner-friendly.

Official Site: https://www.alibabacloud.com/product/cdn

🥈 Tencent Cloud CDN

Best for: Content delivery, video, social/media traffic-heavy sites

Tencent Cloud offers a great experience for images, video, and content delivery, especially suitable for businesses with large traffic fluctuations or activity spikes.

Ecosystem integration is a plus, but it also shares issues like complex configuration and costs that can scale up quickly.

Official Site: https://www.tencentcloud.com/product/cdn

🥉 CDN07 (High-Defense CDN Solution)

Best for: Businesses needing both Mainland China access AND protection

CDN07's positioning is clear: it's not just about "cheap acceleration," but solving acceleration + high-defense together.

If you've experienced:

• Your site slowing down during attacks
• Ordinary CDNs can't handle the load
• Need a combined Mainland + overseas infrastructure

Then CDN07 is a very practical choice.

Official Site: https://www.cdn07.com/

🏅 Baidu AI Cloud CDN

Best for: News sites, blogs, content-centric websites

Simple to set up, decent stability, search engine friendly. Good for small sites that don't want to deal with complex configurations.

Protection and overseas capabilities are average, but it wins on ease of use.

Official Site: https://cloud.baidu.com/product/cdn.html

🏆 Wangsu Technology (ChinaCache)

Best for: Large clients, customized enterprise projects

A veteran CDN player with deep resources and experience, but leans more towards custom enterprise solutions with higher pricing and entry barriers.

Official Site: https://www.wangsu.com/

7. Final Thoughts:

The real question you should ask is:

Where is MY business getting stuck?

• Is it slow access?
• Or instability?
• Or crashing the moment it's attacked?

Figure this out first, then choose your CDN. You'll avoid many detours and save a lot of wasted money.

Frequently Asked Questions (FAQ)

1. Will CDN Acceleration Definitely Make My Website Faster?

Not necessarily.
The core function of a CDN is to shorten the distance between users and your content. If your site is slow due to poor origin server performance, slow databases, or unoptimized dynamic requests, a CDN can only solve part of the problem.
Simply put, a CDN accelerates "delivery," but doesn't optimize your application logic for you.

2. What's the Fundamental Difference Between a Mainland China CDN and an Overseas CDN?

The biggest differences lie in network environment and compliance requirements.
Mainland China CDN nodes are closer to domestic users, offering lower latency and better stability, but typically require ICP filing and real-name verification.
Overseas CDNs are stronger for cross-border access, protection, and flexibility, but often struggle to deliver optimal speed and stability when serving Mainland users directly.

3. Why is My Access Speed Still Unstable Even After Using a CDN?

Three common reasons:
First, poor node scheduling assigns users to lower-quality routes.
Second, only static resources use the CDN, while dynamic requests still go to origin.
Third, the CDN itself becomes the bottleneck during attacks or abnormal traffic.
In such cases, the issue isn't "having a CDN or not," but what type of CDN you're using.

4. Is ICP Filing Mandatory for Mainland China CDNs?

Yes, for the vast majority of formal Mainland CDNs. This is the current reality.
If your business isn't suitable for filing, forcing a Mainland CDN can lead to problems later.
A more practical approach in such cases is often: an overseas CDN + optimization for Mainland access, rather than强行 using Mainland nodes.

5. Can CDNs Only Accelerate Static Content?

Traditional CDNs primarily accelerated static resources. But now many CDNs support:

• Dynamic acceleration
• TCP/UDP optimization
• QUIC, HTTP/3
  However, actual effectiveness depends on node quality and back-to-origin routes.
  "Supporting a feature" doesn't automatically mean "it works well."

6. Are CDN and High-Defense CDN the Same Thing?

No.
The focus of a regular CDN is content delivery. The focus of a High-Defense CDN is accelerating while also resisting attacks.
If your business frequently faces CC, DDoS attacks, relying solely on a regular CDN often has limited effect.
This is why more and more sites are choosing integrated acceleration + protection solutions.

7. When Should I Consider a "Mainland CDN + Overseas High-Defense CDN" Combo?

This combination is very suitable when you meet all these conditions:

• A high percentage of your users are in Mainland China
• You face risks of attacks or abnormal traffic
• Your business has high stability requirements and cannot frequently switch domains or IPs

This architecture achieves:
Fast access for Mainland users, attack traffic blocked outside, and minimized origin server pressure.

8. Does More CDN Nodes Always Mean Faster Speed?

Not necessarily.
More nodes mean theoretically wider coverage, but what really affects experience is:

• Node quality
• Network route conditions
• Scheduling strategy
  Some CDNs "look like" they have many nodes, but only a few are truly high-performing.

9. Do New or Small Sites Need a CDN from the Start?

If you're a pure content site with low traffic, you can probably start without one.
But if your users are geographically dispersed, or you expect future growth,
Implementing a CDN earlier can actually reduce migration costs later.

10. Where Should Price Rank When Choosing a CDN?

Price is important, but shouldn't be #1.
A more sensible priority order is:
Stability → Attack Resilience → Access Experience → Price.
Because once your site becomes unstable, the money you "saved" will quickly be "paid back" through lost traffic and users.