What is a CDN?

A CDN (Content Delivery Network) is a distribution system designed to scale the delivery of web pages, audio, video, and other Internet-based content. A CDN replicates content in caching servers located in geographically dispersed datacenters. A CDN service should route clients to a server in the nearest datacenter.

A CDN can be used to deliver Wowza Streaming Engine® software streams rapidly and cost effectively. There are two common ways to use a CDN with Streaming Engine software, and an additional method that’s less frequently used.

The first CDN distribution method uses the Wowza Push Publishing feature to push a live stream from  Streaming Engine software to a CDN. Using this feature and RTMP, a stream is pushed from the Streaming Engine software to the CDN. The CDN then passes the stream through to its network for Flash RTMP client play and/or packetizes the stream for HTTP clients. This method supports only live streams.

The second way to employ a CDN is to use Wowza HTTP Origin, a feature in the Streaming Engine software. Using this method, the Streaming Engine software packetizes the stream for HTTP clients. The CDN pulls the “chunks” into its cache and replicates in its network for client play. This method supports both on demand and live streaming to HTTP playback clients. Flash RTMP and RTSP playback clients are not supported.

Some CDN operators may be willing to set up a Wowza live stream repeater edge cluster in their network and use an external (to the CDN) Wowza Streaming Engine server as an origin server. However, this is an unusual situation.

In all cases, playback clients stream from the CDN, not directly from the Wowza Streaming Engine. Therefore, there is no logging of client playback in the Wowza Streaming Engine™ manager and advanced play features that involve the manager directly do not work when using a CDN.

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