Windows Media Server Cache Proxy Functionality

A Windows Media server can cache and proxy content as long as it has an enabled cache proxy plug-in present to define what actions to take in response to a client request. For example, if the requested content is found in cache and is up to date, the plug-in can direct the server to play it on demand. If the requested content is not found, the plug-in can do any of the following:

• Direct the server to disconnect the client.

• Redirect the client to an alternate URL.

• Redirect the client to an alternate proxy.

• Proxy the content to the client from an origin server.

It is important to understand that the plug-in does not perform any work other than specifying policy decisions. The cache proxy server, not the plug-in, contacts upstream servers and proxies content to the client or caches it locally.

Windows Media Services does not include a cache proxy plug-in, but you can create your own to define the policy that the Windows Media server must follow in response to a client request. The following sections discuss the functionality used by the server to respond to policy decisions made by the plug-in.

Section	Description
Proxying Broadcast Streams	Discusses how a Windows Media server caches and proxies a broadcast.
Caching and Proxying On-Demand Streams	Discusses how a Windows Media server caches and proxies an on-demand stream.
Proxying Distribution Requests
Caching and Proxying Server-side Playlists
Differentiating Local Requests from Cache Proxy Requests	Discusses how the server determines whether a client has requested content on the local computer or on another server.
Persisting Cached Content	Discusses refreshing content in the cache to make it reflect content on the origin server.
Checking Content Freshness	Discusses how a cache proxy server determines whether content is up to date.
Identifying a Cache Proxy Server	Discusses how a cache proxy server uses via headers and user agents to identify itself to an upstream server.
Using Protocols	Discusses the protocols that clients can use to connect to upstream servers.
Applying Security by Using Authentication and Authorization	Discusses how a windows Media server acting as a proxy handles authentication challenges from origin servers.
Maintaining Security when Downloading Content	Discusses how to guard against server attacks that either disable the downloading process or attempt to download too much data.
Supporting Multiple Bit Rate Files	Discusses how a Windows Media cache server can download multiple bit rate Windows Media files.
Redirecting Clients	Discusses how a Windows Media server redirects clients to alternate URLs and proxy servers.
Implementing Reverse Proxy	Discusses how to make a Windows Media server act as a reverse proxy.
Binding to Proxy Servers Dynamically	Discusses how a cache proxy plug-in can bind one server to another.
Retrieving Internal Cache Proxy Events	Discusses the event notifications triggered when an internal cache proxy event occurs.
Retrieving External WMI Cache Events	Discusses the external events that you can trap by using Windows Management Instrumentation (WMI).
Subscribing to and Sending Remote Cache Events	Discusses how a Windows Media server acting as an origin server can receive remote cache events from a downstream cache proxy server and how a cache proxy server sends the events to an origin server.

See Also

Concepts

Creating Cache Proxy Plug-ins