Alibaba Cloud Content Delivery Network (CDN) is a globally distributed network of Points of Presence (POPs) that caches your content closer to end users. Instead of routing every request to your origin server, users retrieve content from the nearest POP — reducing latency, improving load times, and offloading traffic from your infrastructure.
Onboarding with CDN is fast and simple. You do not need to adjust your business architecture or perform any complex configurations. Simply add your domain name in the CDN console and complete a few steps to enable global acceleration. To get started, see the Beginners' guide.
How it works
CDN intercepts your domain's DNS resolution and routes each request to the optimal POP. The first time a user requests a resource, the POP fetches it from your origin server and caches it. Subsequent requests for the same resource are served directly from the POP cache.
Example: Your accelerated domain is www.aliyundoc.com. When an end user in Singapore sends an HTTP request, the following happens:
User initiates a request. The end user requests a resource from
www.aliyundoc.com. The request goes to the local DNS server for the domain's IP address.DNS forwards the request. The local DNS checks its cache. If no record exists, it queries the authoritative DNS for
www.aliyundoc.com.CNAME record takes effect. The authoritative DNS returns the CNAME record
www.aliyundoc.com.example.com.Smart scheduling. The local DNS sends a resolution request for
www.aliyundoc.com.example.comto the CDN routing system, which assigns the optimal POP IP address.POP IP is returned. The local DNS receives the optimal POP IP address from CDN.
User accesses the POP. The local DNS returns the POP IP address to the user, who then sends a request to that POP.
POP responds:
Cache hit: The POP delivers the cached resource directly to the user.
Cache miss: The POP fetches the resource from your origin server, caches it according to your configured caching rules, and delivers it to the user. For details on cache expiration, see Configure a time-to-live (TTL) for a cached file.
CDN is optimized for static content — images, videos, HTML, CSS, JavaScript, APK files, and software packages. Dynamic content (API responses, database queries, server-side scripts) is not cached and is forwarded directly to your origin server.
Service architecture
Alibaba Cloud CDN consists of four systems that work together to deliver content efficiently:
Route quality system
Monitors the real-time load and health of all POPs and routes in the cache system. This data is continuously fed to the routing system to inform POP assignment decisions.
Routing system
Determines the optimal POP for each request based on the user's IP address, ISP, and real-time route quality data. Supports multiple routing modes: policy-based, DNS, DNS-over-HTTPS (DoH), and 302 redirect.
Cache system
Uses a two-tier architecture: L1 (edge) POPs serve user requests directly; L2 (regional) POPs act as an intermediate cache layer. If a resource is not available at either tier, the system fetches it from your origin server, then caches it for subsequent requests. This multi-tier design reduces origin traffic and improves delivery efficiency.
Support system
Provides operational capabilities for CDN-accelerated domains:
Resource monitoring (Tianyan): Tracks QPS (queries per second), bandwidth, and HTTP status codes for your accelerated domains.
Data analytics: Analyzes top URLs, page views (PVs), and unique visitors (UVs).
Configuration management: Manages cache rules, such as cached file types and query parameter handling, to maximize the cache hit ratio.
Key capabilities
Alibaba Cloud CDN operates more than 3,200 POPs worldwide — over 2,300 in the Chinese mainland covering all 31 provincial-level regions, and more than 900 in over 70 countries and regions outside the Chinese mainland. Total network bandwidth capacity is 180 Tbps.
| Capability | Description |
|---|---|
| Extensive POP coverage | Routes users to the nearest POP on the same ISP, eliminating latency from long-distance or cross-ISP access. |
| Elastic scalabilityhigh availability | Scales resources dynamically across the global POP network to handle traffic spikes without affecting availability. |
| Intelligent scheduling | Monitors POP health in real time and assigns the optimal POP based on each user's location and ISP. |
| Smart routing | Uses protocol and connection optimization to reduce latency and increase throughput, particularly on weak networks. |
| High cache hit ratio | Serves content from nearby POPs, reducing round trips to the origin server. |
| Reduced IT costs | Offloads your business's computing, bandwidth, and connection requirements to the edge, which lowers your IT costs. |
| Edge computing | Run programmable CDN logic with EdgeScript; process images at the edge. |
| Standard APIsAPIs | RPC-based API operations support GET and POST requests for automated management. |
For a full list of advantages, see Competitive advantages of Alibaba Cloud CDN.
Billing
CDN charges for basic services and value-added services separately.
Basic services — two billing methods:
| Method | Best for |
|---|---|
| Pay-by-traffic (default) | Variable or unpredictable traffic patterns |
| Pay-by-peak-bandwidth | Steady, high-volume traffic where peak bandwidth is predictable |
Value-added services — billed separately based on usage:
Static HTTPS requests
Static QUIC requests
Real-time log deliveries
For full pricing details, see Billing of basic services and Billing of value-added services. For pricing rates, see CDN Pricing.
Choose between CDN, DCDN, and ESA
Alibaba Cloud offers three content delivery products. Use this table to identify which fits your use case.
| CDN | Dynamic Content Delivery Network (DCDN) | ESA | |
|---|---|---|---|
| Best for | Static content delivery at high bandwidth and traffic volumes — mobile app updates, game packages, video on demand, image- and text-based websites. | Mixed or fully dynamic workloads — online shopping, payments, interactive chat, online education, global multiplayer games, financial services. | Workloads that need advanced security, edge computing, or integrated DNS — gaming, e-commerce, finance, retail. |
| Coverage | Chinese mainland only / Global / Global (excluding the Chinese mainland) | Chinese mainland only / Global / Global (excluding the Chinese mainland) | Chinese mainland only / Global / Global (excluding the Chinese mainland) |
| Acceleration | Primarily static content. Caches resources on 3,200+ POPs based on cache policies. Dynamic requests go directly to the origin server. | Pure dynamic acceleration and hybrid dynamic-static acceleration. Selects optimal routes for non-cacheable requests using intelligent routing. | Static and dynamic cache acceleration, plus scheduled cache prefetch, cold resource cache retention, and cache analysis. |
| Protocol support | Application: HTTP, HTTPS, QUIC. Network: IPv4, IPv6. | Application: HTTP, HTTPS, WebSocket. Transport: TCP, UDP. Network: IPv4, IPv6. | Application: HTTP, HTTPS, WebSocket. Transport: TCP, UDP. Network: IPv4, IPv6. |
| Scheduling | DNS scheduling, DNS-over-HTTPS (DoH) scheduling, 302 redirect. | DNS scheduling, DoH scheduling, 302 redirect. | High-performance DNS scheduling, DoH scheduling, 302 redirect. |
| Edge computing | EdgeScript for programmable logic; image processing. | EdgeRoutine (ER) for edge programs (A/B testing, prefetching); EdgeScript; image processing. | Edge Functions and Pages (JavaScript on POPs); Edge Storage (key-value store); Edge Container (containerized compute). |
| Security | Referer-based hotlink protection, URL signing, IP blacklists and whitelists. | Basic WAF protection, anti-DDoS protection, basic bot protection. | Integrated WAF with custom rules, Tbps-level anti-DDoS (Enterprise), bot protection with SDK, AI-based protection, origin protection. |
| Integrated DNS | — | — | Anycast DNS with average global resolution under 30 ms. |
| Log analysis | Standard logs, real-time log delivery. | Standard logs, real-time log delivery. | Traffic analysis, standard logs, real-time log delivery, real-time log monitoring. |
Static content refers to files that are identical across requests: images, videos, HTML, CSS, JavaScript, APK files, and compressed archives.
Dynamic content refers to content that varies per request: server-side scripts (ASP, JSP, PHP), API endpoints, and database responses.
For more information, see What are static content and dynamic content?
Management tools
Manage CDN through the console or API after creating and logging in to an Alibaba Cloud account.
CDN console: A web-based interface for configuring domains, cache policies, and monitoring. See the User Guide.
API: RPC API operations supporting GET and POST requests. See the API Reference.
Related services
| Product | How it works with CDN |
|---|---|
| DCDN | Accelerates both static and dynamic content separately for scenarios where CDN alone is insufficient. |
| Object Storage Service (OSS) | Use OSS as the origin to improve website access speed and reduce OSS Internet egress costs. |
| ApsaraVideo Live | Delivers live streams with integrated media storage, transcoding, access control, and CDN acceleration. |
| ApsaraVideo VOD | Reduces buffering for video-on-demand with CDN-backed content delivery. |
| Alibaba Cloud DNS | Provides stable DNS resolution and scheduling to ensure smooth access. |
| Elastic Computing Service (ECS) | Use an ECS instance as the origin server to improve availability and reduce bandwidth costs. |
| Server Load Balancer (SLB) | Set a Server Load Balancer instance as the origin address to distribute traffic and reduce origin load. |
Best practices
What's next
Once you've reviewed billing and confirmed CDN fits your use case, activate CDN and follow the Beginners' guide to add your first domain and enable acceleration.