Overview of NetCache as a streaming media cache

What is a NetCache streaming media cache?

Network Appliance uses the term streaming media cache to describe a NetCache appliance that is configured to handle any or all of the following streaming media protocols:

Microsoft Media Streaming (MMS) for Windows Media, from Microsoft Corporation
Real Time Streaming Protocol (RTSP) for streaming, for example, QuickTime from Apple Corporation, RealSystem from RealNetworks

You can configure a streaming media cache for DNS caching also.

When a streaming media cache is deployed between clients and a streaming media server, streaming requests that would otherwise have been sent directly to the streaming server are sent to the cache.

You must obtain a license from Network Appliance for each streaming media service you want to run--RTSP for RealNetworks, RTSP for QuickTime, and MMS.

Note
NetCache can also be configured as a streaming accelerator to cache and split content from one or more streaming servers that you identify and provide that content to clients that request it. In contrast, when NetCache runs as s streaming media cache, it acts as an agent for the browser, requesting streaming media content for clients and caching and splitting that content so that it can be delivered directly to remote offices. See Chapter 6, Deploying NetCache as an Accelerator, for more information.

Support for live and on-demand streaming media presentations

A streaming media cache handles both live streams and on-demand streams. See Overview of NetCache support for live streams and NetCache support for on-demand streams for information about the differences in how NetCache handles these two types of streaming media presentations.

Benefits of adding a streaming media cache to the network

Adding a streaming media cache to the network can benefit you in the following ways:

Bandwidth savings
NetCache can help you save bandwidth in the following ways:
- By adding a streaming media cache to the network, you can significantly reduce the number of round trips to the streaming server for live streaming media presentations.
- By deploying streaming media caches close to users, you can reduce the number of requests that are sent across the network to the streaming server.
  For example, if your organization is large or spans multiple regions, you can save considerable internal bandwidth by deploying your streaming media caches in separate locations, close to users. The result is that fewer requests are sent across the network to the streaming server.
  
  Note
  You can use the NetCache bandwidth allocation feature to allocate a specific amount of bandwidth to a particular protocol.
Improved quality of streaming media delivered to clients
Streaming media is time dependent and sensitive to changing network conditions. The closer the streaming media content to is to clients, the better the playback experience will be because packets are more likely to be delivered at the constant rate required for smooth playback.
Might eliminate the need to purchase additional streaming servers
If you own the streaming server, deploying a streaming media cache might eliminate the need to purchase additional streaming servers as the volume of streaming traffic increases. The reason is that clients connect to the streaming media cache instead of to the streaming server.

A streaming server can handle only a finite number of connections. By deploying a streaming media cache, you can off-load connections that your streaming servers would have had to handle.

Supported media player versions

NetCache supports the following media player versions:

RealNetworks RealPlayer and later
Microsoft Windows Media Player 6 and later
Apple QuickTime 4 and later

Client logging information provided by NetCache

Many streaming media content providers require that clients send logging information back to the streaming server so that information can be collected for billing, advertisement revenue, performance analysis, and other purposes. When configured to do so, a streaming media cache forwards client logging information to the streaming server for every client that received a stream.

For MMS, NetCache tracks logging information and sends logging packets to the Windows Media server even if Windows Media media players crash. This type of functionality is not available for RealNetworks.

If a streaming server requires client authentication

NetCache does not perform authentication for streaming clients. If a streaming server requires client authentication, NetCache establishes a connection to the streaming server and forwards the authentication information given by the client.

NetCache forwards the authentication information for every client--even if NetCache can resolve a request.

Note
NetCache does not split RealNetworks streams that require user authentication. Every RealNetworks authenticated stream must be treated as a unique stream because of pay-per-view, pay-per-time, and other commerce restrictions.