What is CDN

Last Updated: Feb 02, 2018


Alibaba Cloud Content Delivery Network, shortened to CDN, is a distributed network built on, and overlaying, the bearer network, and is composed of edge node server clusters distributed across different regions. A CDN replaces the traditional data transmission mode centered on web servers.

Alibaba Cloud CDN delivers the source content to edge nodes, and works to a precise scheduling system. It distributes user requests to the most suitable nodes, allowing the user to retrieve the content they need as quickly as possible, reducing congestion of traffic across the Internet, and increasing the response speed of users visiting websites.

The process for http request handling, after using CDN is as follows:


Function introduction

Node cache

  • The object heat algorithm and hierarchical HOT cache resources allow for precise resource acceleration.

  • The high-performance cache system design, use of multiple, balanced CPU cores, and efficient and control of memory maximizes SSD IOPS and throughput.

  • Each node provides high-speed read/write SSD storage. In combination with the SSD acceleration capabilities, this greatly reduces user access waiting time and improves availability.

  • Smart compression effectively reduces the size of the content transmitted by users, accelerating distribution.

  • Page optimization removes spaces, line breaks, TABs, annotations, and other redundant page content, reducing page sizes.

  • Multiple JavaScript/CSS files are combined into a single request, reducing the number of requests.

Precise scheduling

Alibaba Cloud CDN allocates scheduling domains that improve the overall speed of sites. It caters for a variety of sites such as portal information site, multimedia audio and video site, game site, mobile apps and more. CDN benefits include:

  • A scheduling system that supports scheduling for millions of domain names with a single machine.

  • Finer control capabilities and protocol scalability in order to help reduce costs.

  • Multi-level scheduling policies so that node failure will not affect user availability.

  • Multi-system interaction that seamlessly coordinates with security defense systems, refresh systems, and content management systems.

  • Real-time data scheduling and support for node-level traffic prediction which improves the quality and accuracy of scheduling.

Business support for multiple scenarios

  • The audio and video incremental on-demand service provides low buffering times, a smooth playback experience, and supports MP4 and FLV video formats.

  • Resource link authentication and custom authentication keys are supported to ensure the security of your media resources and provide protection against leeching.

  • Through integration with multiple Alibaba Cloud services, CDN works seamlessly with different services to increase cloud resource access and download speeds. Such services include:

    • Object Storage Service (OSS), which works with CDN to accelerate website access and effectively reduce OSS Internet traffic fees.

    • Elastic Compute Service (ECS) works with CDN to increase site availability, protect the origin site information on the server, and reduce bandwidth usage cost.

    • Server Load Balancer for the origin site address to go back to the source for data, reducing the retrieve from the origin bandwidth pressure.

  • CDN also supports non-Alibaba Cloud origin sites and provides unobstructed access and rapid deployment of acceleration services following resource reviews.

  • Alibaba Cloud live streaming media service provides an integrated solution for media asset storage, slicing and transcoding, access authentication, and content delivery acceleration.


  • Use the self-help console for minute-level deployment of all nodes using custom configurations.

  • Use the CDN console to add, delete, modify, and query self-configured domain names, as well as set node cache acceleration policies, anti-leeching measures, http header information, etc. You can also enable different types of acceleration and optimization functions as needed. Learn more.

  • The open and scalable CDN APIs enable flexible deployment, fast operations, precision usage, and timely monitoring of CDN domains, distribution resources, and monitoring data. It can also be used with the APIs of other Alibaba Cloud products for a custom, multi-platform portal. Learn more.

Real-time monitoring

  • The all-round information monitoring feature provides multi-dimensional support for resource distribution.

  • Full network monitoring, data analysis, and resource report downloads, provide a wide range of monitoring information, including information on bandwidth traffic, access quality, visitor data, popularity analysis, and security protection.

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