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Dynamic Content Delivery Network:Before you start

Last Updated:Feb 23, 2024

This topic describes the requirements and limits that apply to domain names when you use Alibaba Cloud Dynamic Content Delivery Network (DCDN). Make sure that your domain names and the related content conform with the requirements to prevent losses that may result from regulatory violations.

Item

Description

IoT card

According to the Notice on Printing and Distributing the Trial Implementation Guidelines for the Classification and Security Management of IoT Cards (MIIT Network Security Letter [2020] No. 1173) set forth by the Ministry of Industry and Information Technology (MIIT) of the People's Republic of China, DCDN cannot provide acceleration services for devices that use IoT cards in the Chinese mainland. When devices that use IoT cards attempt to access DCDN point of presences (POPs), these devices may fail to establish connections to the IP addresses of the POPs.

Content moderation

Alibaba Cloud reviews the content served on all accelerated domain names. Domain names that cannot be accelerated by DCDN include but are not limited to:

  • Domain names of websites whose content is inaccessible or does not provide valid information

  • Domain names that point to illegal private game servers

  • Domain names of websites that provide multiplayer role-playing games and card games

  • Domain names of websites that provide unauthorized software downloads

  • Domain names of websites for peer-to-peer (P2P) lending

  • Domain names of unofficial lottery websites

  • Domain names of websites of unlicensed hospitals and pharmaceuticals

  • Domain names of websites that contain illicit content, such as pornography, drugs, and gambling

Note
  • You are legally responsible for the content that is hosted on your accelerated domain name. DCDN regularly reviews the content served on accelerated domain names. If DCDN detects that illicit content is served on a domain name, the system immediately disables or blocks the domain name. In serious cases, DCDN may permanently block all domain names that belong to the Alibaba Cloud account.

  • For example, if you add a wildcard domain name, such as *.example.com, to DCDN and a specific domain name (a.example.com) matches the wildcard domain name contains illicit content, DCDN disables the wildcard domain name (*.example.com).

  • If a domain name fails the review, you can check the reason for rejection on the Domain Names page in the DCDN console. Then, you can modify the content based on the rejection details and re-submit the domain name for review.

Origin fetch

  • HTTP request header, which cannot exceed 300 bytes

  • Timeout period

    By default, the timeout period for back-to-origin requests that are transmitted over Transmission Control Protocol (TCP) is 10 seconds. The timeout period for back-to-origin requests that are transmitted over HTTP is 30 seconds.

  • Response header

    If an origin server does not respond to Content-Type, DCDN automatically adds Content-Type:application/octet-stream.

  • Automatic conversion from HEAD to GET for back-to-origin requests

    By default, HEAD requests are sent to DCDN POPs before the requests are redirected to origin servers. When this happens, HEAD requests are converted to GET requests. If you want to preserve the HEAD requests, go to the Custom Origin HTTP Header tab in the DCDN console, and configure the following header. For more information, see Configure HTTP request headers.

    • Custom header: Ali-Swift-Fwd-Head

    • Value: on

Bandwidth throttling

According to the Alibaba Cloud International Website Product Terms of Service, if you expect traffic spikes on DCDN-accelerated services, you need to contact us to apply for burst bandwidth at least 3 business days in advance. For major events including but not limited to the Spring Festival Gala and Double 11 Global Shopping Festival, you need to apply for burst bandwidth at least 1 month in advance. If the application is successful, Alibaba Cloud guarantees the availability of your services when the burst bandwidth is within the level agreed upon by both parties. If you do not apply for burst bandwidth or the application is unsuccessful, Alibaba Cloud reserves the right to take measures such as bandwidth throttling to ensure service-level stability for other Alibaba Cloud customers. Alibaba Cloud is not responsible for the reduced availability caused by these measures.

File

  • File cache

    • Responses whose Cache-Control directives do not allow caching: If the request to a file whose size is larger than 100 MB is a cache miss, DCDN closes the connection after the amount of data that is transmitted from the origin server reaches 100 MB.

    • Responses whose Cache-Control directives allow caching: DCDN can cache files that are up to 500 GB in size.

  • File upload

    You can upload files to origin servers by using DCDN. Each file can be up to 300 MB in size.

Stress testing

If you want to run stress tests on a domain name that is accelerated by DCDN, you must report the tests to Alibaba Cloud at least three days in advance. Otherwise, the following issues may occur:

Stress tests on the number of queries per second (QPS) may trigger HTTP flood protection rules of DCDN. As a result, the domain name is added to the sandbox. For more information, see Introduction to sandboxes.

Length of an individual URL or HTTP request header, and total length of URLs and HTTP request headers

HTTP/2:

  • If the default setting of the NGINX directive is http2_max_field_size=32KB, the length of an individual HTTP request header or an individual URL cannot exceed 32 KB. Otherwise, the HTTP 414 status code is returned.

  • If the default setting of the NGINX directive is http2_max_header_size=128KB, the total size of all HTTP request headers and URLs cannot exceed 128 KB. Otherwise, the HTTP 400 status code is returned.

HTTP/1.1: For the large_client_header_buffers directive, number is set to 4 and size is set to 64 KB. In this case, the length of an individual HTTP request header or an individual URL cannot exceed 64 KB. Otherwise, the HTTP 414 status code is returned. The total length of all HTTP request headers and URLs cannot exceed 256 KB. Otherwise, the HTTP 400 status code is returned.

Request method

DCDN supports the GET, PUT, POST, HEAD, and OPTION request methods.

Note
  • If you want your website to support DELETE and PATCH requests, enable dynamic content delivery.

  • PUT allows HTTP requests that contain a request body (BODY) or do not contain a request body (Content-Length=0).

  • POST supports chunked encoding and allows HTTP requests that contain a request body (BODY) or do not contain a request body (Content-Length=0).

  • For cached static resources, POPs convert HEAD requests to GET requests before the requests are redirected to the origin server by default. If you want POPs to redirect HEAD requests to the origin server, you can configure the following request header on the Custom Origin HTTP Header tab in the DCDN console. For dynamic resources, which are not cached, POPs do not convert HEAD requests to GET requests. For more information, see Configure HTTP request headers.

    • Custom header: Ali-Swift-Fwd-Head

    • Value: on

API call for each account

You can call this API up to 1,000 times per second per account. If this upper limit is reached, the following message is returned:

ErrorCode:Throttling
ErrorMessage:Request was denied due to flow control.