MMS streams are cached based on the contents of the stream, rather than the URL. If different users access the same stream from multiple URLs, only one copy is kept. This applies whether the stream is filled via HTTP, TCP, or UDP, and regardless of which service type (forward, transparent, or accelerator) is used.
Users are able to access a copy of the stream using any of the three protocols. For variable bandwidths streams, each bandwidth is stored as a separate object. This ensures that only the bandwidths currently being used are cached.
One way to ensure complete caching of streams is to preload streams into cache that you know users will be requesting later. This can be done via the site download feature of Excelerator 2.3. You can configure Media Excelerator to load the streams during off hours when bandwidth demands on your Internet connection are low.