Terms

Last Updated: May 14, 2018

Domain name

A domain name is a server or network system name that identifies IP resources connected to the Internet. All domain names are unique worldwide.

CNAME record

A Canonical Name (CNAME) record is a type of resource record in the Domain Name System (DNS) used to specify that a domain name is an alias for another domain, which is the “canonical” domain.

CNAME domain name

CDN domain acceleration needs to use the CNAME records.

You will receive an accelerated domain name which is the CNAME domain name (this domain name should be *.*kunlun.com) after CDN acceleration on the Alibaba Cloud console is configured. The domain name resolution is then formally transferred to Alibaba Cloud after you reference the domain name *.*kunlun.com following the CNAME operation.

All requests for this domain name will be transferred to the Alibaba Cloud CDN nodes.

Acceleration domain name

An acceleration domain name is provided by you for CDN acceleration service. It can be applied in a website, an email address, and an FTP server.

DNS

DNS stands for Domain Name System. It refers to the domain name resolution service. Its function on the Internet is to convert a domain name to an IP address that can be recognized by the network.

The domain name and IP address are synonymous to each other and the task of converting between the two is called domain name resolution. Domain name resolution requires a dedicated domain name resolution server to complete the task, and the entire process runs automatically.

For example, the domain name www.baidu.com is automatically converted to 220.181.112.143.

Edge node

Edge node is also referred to as CDN node or cache node.

Edge node is a concept proposed in contrast to the complex structure of the network. It refers to network nodes with a smaller number of accessible links. This improves the response capability and connection speed for the end user.

Edge nodes are used to store webpage contents and objects with a higher traffic volume in specialized cache machine on the front-end of the server. This improves the speed and quality of website access.

origin retrieva host

origin retrieval host: The origin retrieval host determines the site to which a origin retrieval request is sent.

Example 1: The origin site is a domain name.If the origin site is www.a.com and the origin retrieval host is www.b.com,the actual origin retrieval request is sent to the IP address resolved from www.a.com corresponding to the site www.b.com on the host.

Example 2: The origin site is an IP address.If the origin site is 1.1.1.1 and the origin retrieval host is www.b.com,then, the actual origin retrieval request is sent to the site www.b.com on the host corresponding to 1.1.1.1.

Protocol-based origin retrieval request

The same protocol is used for sending origin retrieval requests and accessing resources from the client. That is, if the client initiates an HTTPS request for resources but the resources are not cached on the CDN node, the node initiates a origin retrieval HTTPS request for the resources. The same is true for HTTP requests.

Filter parameters

When a URL request includes a question mark (?) and request parameters are sent to a CDN node, the CDN node determines whether to send the request to the origin site. If the “Filter Parameter” function is enabled, after the request arrives at the CDN node, the URL without parameters will be intercepted and requested against the origin site. In addition, the CDN node keeps only one copy. If the “Filter Parameter” function is disabled, different copies are cached on the CDN node for different URLs.

Example of use

The http://www.abc.com/a.jpg?x=1 URL request is sent to a CDN node.After the “Filter Parameter” function is enabled, the CDN node initiates the http://www.abc.com/a.jpg request (ignore the parameter x=1) to the origin site. After the origin site returns a response, the CDN node keeps a copy. Then, the origin site sends a response on http://www.abc.com/a.jpg to the terminal. For all requests similar to http://www.abc.com/a.jpg? parameters, the origin site responds to the content of CDN copy http://www.abc.com/a.jpg.When the “Filter Parameter” function is disabled, different copies are cached on the CDN node for different URLs. For example, different contents are returned by the origin site in response to http://www.abc.com/a.jpg?x=1 and http://www.abc.com/a.jpg?x=2.

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