From time to time, you may identify URL records which has a URL Scheme (or Record Type as shown in NetAnalysis) of MMS.  Figure 1 shows an example of such a record.  These records relate to streaming video from a Microsoft Media Server (MMS).


Figure 1


Microsoft Media Server (MMS)

Microsoft Media Server (MMS) is the name of Microsoft's proprietary network streaming protocol used to transfer unicast data in Windows Media Services (previously called NetShow Services). MMS can be transported via UDP or TCP. The MMS default port is UDP/TCP 1755.  

Microsoft deprecated MMS in favor of RTSP (TCP/UDP port 554) in 2003 with the release of the Windows Media Services 9 Series, but continued to support the MMS for some time in the interest of backwards compatibility.  Support for the protocol was finally dropped in Windows Media Services 2008.  However, Microsoft still recommends using "mms://" as a "protocol rollover URL".

As part of protocol rollover a Windows Media Player version 9, 10, or 11 client opening an "mms://" URL will attempt to connect first with RTSP over UDP and if that fails it will attempt RTSP over TCP.  After an RTSP attempt fails, Windows Media Player versions 9 & 10 will attempt MMS over UDP, then MMS over TCP.

If using Windows Media Player 11 and an RTSP attempt fails, or if using a previous version of Windows Media Player and MMS fails, a modified version of a HTTP over TCP connection will be attempted.  This modified version is referred to by some third parties as MMSH, and by Microsoft as MS-WMSP (Windows Media HTTP Streaming Protocol).

The URI scheme "mms://" has also been proposed to be used for the unrelated Multimedia Messaging Service (MMS) protocol.   For several years, developers of the SDP Multimedia download tool reverse engineered the MMS protocol and published an unofficial documentation for it, until Microsoft finally released the protocol specification in February 2008.