Alibaba Cloud CDN is a global network of points of presence (POPs) that are distributed across the globe. Alibaba Cloud CDN serves to reduce back-to-origin traffic. This in turn prevents network congestion and ensures that content is delivered with minimal latency across regions in various use cases.
Alibaba Cloud CDN global network is made up of more than 2,800 strategically located POPs. Spanning over 2,300 POPs located across 31 provinces in the Chinese mainland, and over 500 POPs located in more than 70 countries and regions, including Hong Kong (China), Macao (China), and Taiwan (China), Alibaba Cloud CDN has a global networking capacity of up to 150 Tbit/s. For more information about POP distribution, see POP distribution.
Alibaba Cloud CDN caches resources from your origin servers on POPs located across the globe. Whenever customers access your resources, the resources are served from the nearest POP instead of the origin server. This helps prevent lengthy back-to-origin requests and reduces loads on origin servers, delivering better experience to your customers and reducing back-to-origin costs. Alibaba Cloud CDN also provides IPv6 support on some POPs.
Alibaba Cloud CDN is a simple and efficient method to deliver content to your customers. As a content provider, you can serve your content through Alibaba Cloud CDN with just a few clicks in the console. You no longer have to worry about setting up complex configurations or modifying your code to be compatible with your content delivery provider. After you add your domain name to Alibaba Cloud CDN, your content is automatically cached to our global content delivery network. For more information about how to activate and use Alibaba Cloud CDN, see Getting started.
- Globally distributed POPs: Alibaba Cloud CDN redirects requests to the nearest POPs that belong to the same Internet service provider (ISP) as the clients, eliminating network latency when traffic is passed between different ISPs.
- Scalable resources: Alibaba Cloud CDN provides more than 2,800 globally distributed POPs to ensure resource scalability and service availability.
- Intelligent routing: Alibaba Cloud CDN monitors the health status of POPs in real time, and redirects requests to optimal POPs selected by the routing system based on client locations and ISPs.
- Intelligent connections: Alibaba Cloud CDN uses optimization strategies such as protocol optimization and connection optimization to reduce network latency and accelerate content delivery, especially over networks with limited connectivity.
- Intelligent caching: Alibaba Cloud CDN caches popular content across its global network, improving cache hit ratio on POPs closest to clients.
- Lower IT costs: Aside from content delivery capabilities, POPs also provide computing, bandwidth, and networking capabilities, which you can make use of to reduce investment in IT hardware.
- High bandwidth capacity: Alibaba Cloud CDN provides up to 150 Tbit/s of networking capacity.
- Standardized APIs: Alibaba Cloud CDN provides a comprehensive suite of user-friendly APIs.
For more information, see Competitive advantages of Alibaba Cloud CDN.
- Routing system
The routing system provides a policy center and supports Domain Name System (DNS) resolution, HTTPDNS, and 302 redirection. When a client sends a request, the request is resolved by DNS resolution and subsequently processed by the routing system.
- Route quality system
The route quality system monitors the loads and health status of POPs and routes in real time. This information is shared with the routing system, which uses this information to select optimal routes for requests. The routing system also takes additional information included in the origin IP address, such as the ISP and region of the requests, into account when selecting the optimal route.
- Caching system
The caching system redirects requests to POPs based on the access points where the requests originate. If the requested resource is already cached on the POPs, the resource is directly served to the client. Otherwise, the request is redirected to the origin server. The retrieved resource is then served to the clients and cached on the POPs. Subsequent requests for the resources are served through the POPs. Alibaba Cloud CDN uses intelligent object algorithms to cache content based on popularity in a multi-level cache. This mechanism allows Alibaba Cloud CDN to reduce the amount of bandwidth resources consumed by back-to-origin routing, and improve user experience.
- Support systemThe support system supports Tianyan (an internal health monitoring system), data intelligence, and configuration management. The support system can monitor resources, analyze data, and manage configurations.
- Resource monitoring: Tianyan can monitor the status of services that are running in the caching system. For example, Tianyan monitors the number of queries per second (QPS), bandwidth, and HTTP status codes for a domain name that is accelerated by Alibaba Cloud CDN.
- Data analytics: You can analyze data, such as the top N most frequently requested URLs, page views (PVs), and unique visitors (UVs) for a domain name that is accelerated by Alibaba Cloud CDN.
- Configuration management: You can create and manage cache expiration rules to improve the efficiency of the caching system. For example, you can create a cache expiration rule for a specified type of file or enable parameter filtering.
How it works
www.aliyundoc.com. The following figure shows how Alibaba Cloud CDN handles an HTTP request from a client in Beijing.
- When the client in Beijing sends a request to retrieve resources from
www.aliyundoc.com, a domain name resolution request is sent to the local DNS server (LDNS) to retrieve the IP address of
- The LDNS checks whether the cache contains the IP address that corresponds to
www.aliyundoc.com. If so, the LDNS directly returns the IP address to the client. If not, the website authorizes the DNS server to query the DNS records of
- After the DNS server retrieves the DNS records of
www.aliyundoc.com, the DNS server returns the CNAME
- The LDNS sends a request to the DNS routing system of Alibaba Cloud CDN to retrieve the DNS records of
www.aliyundoc.com.example.com. Then, the routing system selects an optimal POP on which to serve the content and returns the POP IP address to the LDNS.
- The LDNS receives the IP address returned from the routing system.
- The LDNS returns the IP address to the client.
- The client initiates a request to the received IP address.
- If the requested resource is already cached on the POP, it is directly served to the client, as shown in Step 8.
- If the requested resource is not cached on the POP or has expired, the request is redirected to the origin server. The retrieved resource is served to the client and cached on POPs based on the cache expiration rules, as shown in Step 8. For more information about how to configure a cache expiration rule, see Add a cache rule.
Differences between Alibaba Cloud CDN and DCDN
|Scenario||Game updates, app updates for mobile phones, on-demand videos including long and short videos, and infographic websites.||Online shops, online payments, online chatting, online education, online multiplayer games, and financial management.|
|Acceleration method||Accelerates the delivery of static content and redirects requests for dynamic content to origin servers. Alibaba Cloud CDN is suitable for scenarios that require high bandwidth and process a large amount of network traffic. ||Accelerates the delivery of dynamic content, or both dynamic and static content. |
Supports DNS resolution, HTTPDNS, and 302 redirection.
Supports DNS resolution, HTTPDNS, and 302 redirection.
- Dynamic content refers to the content that is delivered on a per-request basis. The server returns different contents for different requests. Dynamic content includes ASP, JSP, PHP, Perl and CGI files, API requests, and database interactive requests on websites.
|Media website||Purpose-specific website||Resource distribution website|
For more information, see Scenarios.
- Billing rules of basic services: supports the pay-by-data-transfer and pay-by-peak-bandwidth metering methods. The default metering method is pay-by-data-transfer. For more information, see Billing rules of basic services.
- Billing rules of value-added services: The billable items include HTTPS requests for static content, QUIC requests for static content, and real-time log entries. For more information, see Billing of value-added services.
For more information, see CDN pricing.
We recommend that you familiarize yourself with the billing rules of Alibaba Cloud CDN before you activate Alibaba Cloud CDN. For more information, see Activate Alibaba Cloud CDN.
- Alibaba Cloud CDN console
The Alibaba Cloud CDN console is an easy-to-use web console that supports interactive operations. For more information, see Features and Functions and features.
- Alibaba Cloud CDN API
The Alibaba Cloud CDN API provides a remote procedure call (RPC) API that supports GET and POST requests. For more information, see Introduction.
|DCDN||DCDN separately accelerates dynamic and static contents while balancing performance and security capabilities.|
|OSS||If you use an OSS bucket as an origin server, you can use Alibaba Cloud CDN to accelerate content delivery and reduce Internet data transfer fees.|
|ApsaraVideo Live||You can use Alibaba Cloud CDN together with ApsaraVideo Live to achieve media feed storage, video segmentation and transcoding, access authentication, and content delivery acceleration.|
|ApsaraVideo VOD||You can use Alibaba Cloud CDN together with ApsaraVideo VOD to reduce the buffer time and improve playback smoothness.|
|Alibaba Cloud DNS||You can use Alibaba Cloud DNS that is highly available and stable to ensure smooth access to resources.|
|ECS||You can use Alibaba Cloud CDN with ECS to improve website availability, protect information about origin servers, and minimize bandwidth usage costs.|
|SLB||You can specify the IP address of a Server Load Balancer (SLB) instance as the origin address to distribute traffic across multiple servers during the back-to-origin process.|