Configure a Site

What is Media Delivery Site Configuration?

To set up your site to serve content via the CDN, you configure the following components:

• Host - A Media Delivery site configuration must include at least one host. A host is the root configuration for a delivery service. It defines the host domain (for example, www.my-vod.com), the traffic type (vod, live, low latency live, or software downloads), the origin where the content is found, and rules for processing requests and serving content. Optionally, you can define access control lists (ACLs).

  When a site configuration includes multiple hosts, all the hosts must define the same traffic type.

• Origin - The CDN uses the origins configured for the site to acquire content. An origin must be configured for each site host. You may have a single origin host, or multiple origin hosts to enable a failover or load balancing workflow.
  If you want to map a portion of the site to an alternate origin, you do so by defining a path with a path origin. At the path level, you can also define multiple origin hosts to support failover or load balancing.

• Rules - Rules determine how client requests are processed and how content is delivered. For example, rules can be used to manage headers, control caching, enable compression, or improve error handling.

  Rules may be applied at a host or path level. When the CDN receives a request for content located in a particular path, the rules configured for the path are applied.

• Path -To apply custom rules or access control lists (ACLs) to some of your content, or to map a portion of the site to an alternate origin, configure a path. When the CDN receives a request for content located in a particular path, any rules configured for the path are applied.

  The host and path configuration building blocks are almost identical. Initially, a path inherits the host parameters.

  The path configuration incudes a traffic type setting. Make sure that the path traffic type matches the traffic type set for the host.

• Access Control Lists - ACLs can be used to restrict access to resources based on a client's IP address, geographic location, autonomous system number (ASN), or use of anonymizer.

Before we get into the details of how to configure a site, it is important to understand how client requests for content are processed by the CDN.

How Does the CDN Process Client Requests?

Media Delivery works by caching content requested by a client, onto the CDN hosted by the client’s Internet service provider network. With the content physically close to the client, latency is reduced to a minimum.

When the client first contacts your site origin with a request for content, the origin searches for a CDN near the client. Then for the rest of the request session, there are two channels of communication: between the client and the CDN, and between the CDN and the origin.

The simplest scenario works as follows:

A. A client request for content is sent to the CDN.
B. If the content is already cached on the CDN, the CDN sends the content to the client.

When the requested content is not available on the CDN cache, this is what happens:
A. A client request for content is sent to the CDN.
B. The CDN sends a request to the origin for the content.
C. The origin sends the content to the CDN where it can be cached for further use.
D. The CDN sends the content to the client.

The content publisher can define rules that determine exactly how requests are processed and content is delivered. Each rule can be applied generally, or to specific content (paths).

The content publisher can purge or update the content cached on the CDN, at any time.

See the Quick Start for a step-by-step description of the configuration workflow.