1.6 Applicability Statement
The Windows Media HTTP Streaming Protocol is suitable for streaming delivery of real-time multimedia data. The term streaming means that the data is transmitted at some fixed rate or at some rate that is related to the rate at which the data will be consumed (for example, displayed) by the receiver.
The most common use of the protocol is streaming media from a media server by a media player client. It is possible, however, for an encoder to act as the media server. In this case, the media server becomes the client and streams media from the encoder.
This protocol can be appropriate if the client is behind a firewall that only allows HTTP traffic. The Windows Media HTTP Streaming Protocol can be used on TCP port 80, and traffic to that port is usually allowed through by firewalls.
This protocol can also be appropriate if the client sends feedback to the server that can cause the multimedia data that is being transmitted to change or cause the transmission rate to change.
Furthermore, this protocol can be appropriate if the client performs "trick-mode operations" on the multimedia data and prefers the server to execute trick modes on its behalf. The term "trick-mode operation" refers to operations like fast-forwarding and rewinding the data, pausing the transmission, or seeking a different position in the multimedia data stream (2).
If some or all of the preceding applies but the multimedia data is to be transferred over UDP, it might be more appropriate to implement the Real-Time Streaming Protocol Extensions, as specified in [MS-RTSP].
If none of the preceding applies, it might be more appropriate to use HTTP 1.0, as specified in [RFC1945], to download the data, instead of implementing this protocol.