Basic Concepts

Static Content

Static content is the same every time it is delivered to users. It includes images, videos, HTML, CSS, and JS files on websites, software installation packages, APK files, and compressed packages.

Dynamic Content

Dynamic content changes every time it is served to users. It includes ASP, JSP, PHP, PERL, and CGI files on websites, APIs, and database interaction requests.

Acceleration Domain Name

Acceleration domain names are provided by you for CDN acceleration. A domain name is an identification string that defines a realm of administrative autonomy, authority, or control within the Internet, such as a website, an email address, or an FTP server. For example, if you connect example.com to Huawei Cloud CDN, example.com is an acceleration domain name. When a user accesses an acceleration domain name, CDN resolves it to the nearest PoP for faster resource access.

Origin Server

An origin server is the customer's service server, the source of the data accelerated for delivery. If a requested resource is not cached on CDN PoPs, the PoP sends a request to the origin server to pull the resource, returns it to the user, and caches it. Origin servers can be domain names, IP addresses, or Huawei Cloud Object Storage Service (OBS) buckets.

Edge PoP

Edge points of presence (PoPs), also known as CDN PoPs or cache PoPs, require the fewest intermediate steps for users to connect. Compared with direct access to origin servers, PoPs provide faster response and connection.

CNAME Record

A Canonical Name record (CNAME record) is a type of resource record in the DNS that maps one domain name (an alias) to another (the canonical name).

Example:

You have a server that stores some files. Users can access the files through file.example.com, but you want users to access them through data.example.com.
You add a CNAME record to your domain's DNS records to point data.example.com to file.example.com.
Then DNS points all requests for data.example.com to file.example.com, and users get the same content.

CNAME

On the CDN console, after a domain name is added, the system will assign a CNAME (in the form of *.*.c.cdnhwc1.com) to the domain name. Then, add this CNAME to your domain's DNS records and point the domain name to it. After the CNAME record takes effect, all the requests for your domain name will be redirected to CDN PoPs.

DNS

The Domain Name System (DNS) translates human readable domain names into IP addresses. With DNS, users can access servers using their assigned domain names.

For example, when you access xxx.abc.com, the domain name is converted into xxx.xxx.1.1 (an IP address) through DNS. You can use Huawei Cloud DNS or a DNS service from other providers.

Origin Pull

If a CDN PoP does not cache origin content or if cached content has expired, the CDN PoP obtains the requested content from the origin server and returns it to the client.

For example, if you access a URL and the CDN PoP does not cache the content, your request will be sent to the origin server and a response will be returned based on the URL.

Host Header

The origin server determines the IP address of the origin server that an origin pull request is sent to. The host determines which site the origin pull request is sent to.

Example 1: If the origin domain is www.origin.com but the host is www.abc.com, origin pull requests actually go to www.abc.com.

Example 2: If the origin IP address is 192.168.1.1 but the host is www.abc.com, origin pull requests actually go to www.abc.com.

SSL/TLS

Secure Sockets Layer (SSL) is a cryptographic protocol designed to provide communications security over a computer network. Transport Layer Security (TLS) is an improved version of SSL and has now replaced SSL.

Query Parameters

You can filter out query parameters after the question mark (?) in a URL and improve the cache hit ratio.

SWR

stale-while-revalidate (SWR) is a field in the HTTP response header Cache-Control. SWR allows clients to access stale resources until the SWR duration ends. At the same time, CDN pulls and caches the latest resources from the origin server.