Community Blog Content Delivery Network (CDN): Accelerate Distribution of Content Globally

Content Delivery Network (CDN): Accelerate Distribution of Content Globally

Alibaba Cloud Content Delivery Network (CDN) is a scalable and high-performance content delivery service for the accelerated distribution of content to users across the globe.

The Overview of Alibaba Cloud Content Delivery Network (CDN)

Alibaba Cloud Content Delivery Network (CDN) is a distributed network built over the transport network that consists of edge nodes deployed in different regions across the world. Alibaba Cloud CDN caches static and dynamic resources from origin servers to the edge nodes and allows users to retrieve desired content from the edge nodes. Alibaba Cloud CDN reduces workloads on origin servers to prevent network congestion. You can use Alibaba Cloud CDN to accelerate website content delivery in different regions or scenarios.

Alibaba Cloud has deployed over 2,800 nodes across the world. More than 2,300 nodes are deployed across 31 provincial regions inside mainland China. Among these nodes, a large number of them are deployed in first-tier cities and provincial capitals. More than 500 nodes are deployed across 70 regions outside mainland China, including China (Hong Kong), China (Macao), and China (Taiwan). Alibaba Cloud CDN supports a total bandwidth capacity of 130 Tbit/s and 10 GE network interface controllers (NICs). Each CDN node provides 40 TB to 1.5 PB of data storage, and a bandwidth capacity of 40 Gbit/s to 200 Gbit/s.

During the use of Alibaba Cloud CDN, you can determine the acceleration effect based on multiple factors. These factors include the latency, download speed, website content loading speed, packet loss rate, the ratio between the number of back-to-origin requests, and the total number of requests, and the cache hit ratio.

The Architecture of Alibaba Cloud Content Delivery Network (CDN)

In this example, your accelerated domain is www.a.com. The following figure shows how Alibaba Cloud CDN works after receiving an HTTP request from a user in Beijing.


  • Before the user in Beijing sends a request to query a specific resource under www.a.com, the user initiates a domain name resolution request to the local DNS (LDNS) server.
  • The LDNS server checks whether there is a DNS record corresponding to www.a.com in the local cache. If yes, the LDNS server directly returns the IP address to the user. If no, the LDNS server queries the IP address from the authorized DNS server.
  • After the authorized DNS server resolves www.a.com, it returns the IP address to which the canonical name (CNAME) www.a.tbcdn.com is mapped to the LDNS server.
  • The LDNS server sends a domain name resolution request to the Alibaba Cloud DNS scheduling system. The Alibaba Cloud DNS scheduling system then returns the IP address of the optimal node to the LDNS server.
  • The LDNS server receives the resolved IP address returned by the Alibaba Cloud DNS scheduling system.
  • The user receives the resolved IP address.
  • The user initiates an access request to the received IP address.

The Benefits of Alibaba Cloud Content Delivery Network (CDN)

Stability and high speed

  • Advanced distributed system architecture: more than 2,300 nodes in Mainland China, and more than 500 nodes outside Mainland China, including China (Hong Kong), China (Macau), and China (Taiwan). Alibaba Cloud CDN nodes are deployed across six continents. Alibaba Cloud CDN provides the largest number of nodes in Mainland China.
  • Sufficient bandwidth and storage resources: a bandwidth of more than 40 Gbit/s per node and a total bandwidth of 130 Tbit/s.
  • Stable performance and high efficiency: a cache hit ratio of more than 95%, a video smooth streaming rate of more than 95%, and millisecond-level response time.
  • Comprehensive monitoring and service systems: 24/7 network-wide monitoring, and intelligent monitoring and scheduling based on service quality.


  • You can elastically scale resources and pay for the resources based on the actual usage. You can achieve network-wide coverage across service providers and regions.
  • Alibaba Cloud CDN provides pay-by-traffic and pay-by-bandwidth billing methods. Both billing methods are used on a pay-as-you-go basis. You can select a billing method based on your business needs.
  • Alibaba Cloud CDN automatically responds to site traffic spikes and makes adjustments, which effectively reduces workloads on origins.

Ease of use

  • Alibaba Cloud CDN provides an easy-to-use console. In this console, you can use a wide range of custom configuration items to add, delete, modify, and query domain names. Alibaba Cloud CDN also allows you to customize hotlink protection rules, cache policies, and HTTP response headers.
  • Alibaba Cloud CDN provides a wide array of API operations. You can call these API operations to use Alibaba Cloud CDN features including service activation, content refresh, monitoring, and log download and distribution.

High efficiency and intelligence

The Alibaba Cloud CDN console can automatically and quickly respond to standardized configuration requests that you submit, which improves user experience. Compared with other CDN services, Alibaba Cloud CDN does not require manual intervention in this process, which minimizes the response time.

The Scenarios of Alibaba Cloud Content Delivery Network (CDN)

You can use the content delivery network (CDN) services in the following scenarios: static content delivery acceleration, dynamic content delivery acceleration, and secure acceleration. Alibaba Cloud CDN serves to accelerate only the delivery of static content.

  • Image and small file distribution: Your websites or applications offer downloads of images and small files in formats such as HTML, CSS, and JavaScript.
  • Delivery of large files: Your websites or applications offer downloads of files larger than 20 MB, such as game applications, client applications, or mobile apps.
  • ApsaraVideo for VOD: Your websites or applications offer on-demand video streaming or short video streaming. Mainstream media formats such as MP4 and FLV are supported.
  • DCDN: Dynamic Route for CDN (DCDN) is an independent Alibaba Cloud service and can accelerate the delivery of dynamic content. You can also use DCDN to separately accelerate the delivery of static and dynamic content.
  • SCDN: If your website is vulnerable to attacks and requires delivery acceleration, you can use SCDN to reinforce the security of your workloads.

Related Product:

Content Delivery Network (CDN)

You can use the content delivery network (CDN) to deliver content to users from the nodes that are nearest to them, accelerating the response to user requests and increasing the response rate. CDN also resolves the delivery latency problem that is usually caused by distribution, bandwidth, and server performance issues. CDN has been applied in multiple scenarios, including site acceleration, on-demand streaming, and live streaming.

Related Learning Course:

CDN Learning Path

Alibaba Cloud Content Delivery Network (CDN) caches contents at physical nodes, then strategically deliver them to end-users from the nearest node.

Related Blog:

Alibaba Cloud CDN: The Best Choice When You Enter the APAC Market

In the 5G era, users will experience high-speed uploads and downloads, while 4K and 8K live streaming will create both benefits and challenges for content delivery networks (CDNs.) As the need for intelligent computing steadily increases, edge computing will become a trend in the industry. By using a CDN, you can deploy more computing and storage resources to the edge, where your customers can conveniently access and configure them. Many cloud service providers offer CDNs as core capabilities for their infrastructure products.

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