Using URLs to direct requests to NetCache

About client access with URL modification

You can direct MMS or RTSP client requests to NetCache by providing clients with streaming URLs that contain the IP address (or host name) of the streaming media cache and the IP address of the streaming server. For example:

mms://cache/server/file

rtsp://cache/server/file

How URL modification might be used

URL modification is especially useful in the following situations:

If you want to dynamically generate URLs to direct clients to the closest or least loaded streaming media cache and streaming server
When you want to keep clients from directly accessing the streaming server

Example of URL modification to direct clients to specific caches

A content distributor that owns both the streaming media cache and streaming media server could create a CGI script to dynamically generate URLs that direct clients to the streaming media cache and streaming server that have the lightest load. For example:

rtsp://least-loaded-cache/least-loaded-server/file.rm

The preceding URL directs the client to the streaming media cache with the lightest load. The streaming media cache then requests the content from the streaming server identified as having the lightest load.

Example of URL modification to isolate streaming servers from clients

Content distributors that do not want to provide clients with direct access to their internal streaming servers can provide URLs of the following form on their external Web site:

rtsp://external-cache/internal-server/file.rm

The preceding URL directs clients to the external streaming media cache. After receiving the client request, the streaming media cache then accesses the internal streaming server. To prohibit clients from accessing any other servers on the internal network, the content distributor could then construct ACLs that limit client access to only specified servers.

Description of URL modification syntax

Consider the following syntax example:

rtsp://cache/server/file

In the preceding example, cache is the IP address or host name of the streaming media cache, server is the IP address or host name of the streaming server, and file is the name of the streaming media content.

When the streaming media cache receives a client request for a URL of this type, it strips off the cache portion (IP address or host name of the streaming media cache) of the URL to find the IP address of the streaming server. The streaming media cache then requests content from the streaming server.

URL modification for HTTP progressive download

For URL modification and HTTP progressive download of streaming media to work properly, you must configure additional options. For more information, see "Setting up URL modification for HTTP progressive download" in the streaming media section of the Contents tab in the online Help.