This article relates to Cisco TelePresence Content Server.
Q. How does protocol rollover work on Windows Media Player and how does this affect the Content Server?
A. Protocol rollover is a mechanism used by Windows Media Player to offer alternative transport protocols in the event that a chosen protocol is not available or fails.
The three protocols available are:
MMS - Microsoft Media Server (port 1755)
RTSP - Real Time Streaming Protocol (port 554)
HTTP- Hypertext Transport Protocol (port 8080 on the TCS)
When the player tries to connect to the Content Server's Windows Media Server from a url with mms://ip_address/file.wmv, it tries to use RTSP on port 554. If that fails, it tries to connect using MMS (port 1755) for information on which protocols are available. If HTTP is enabled, the player then tries to connect via http on port 80. (Note that the Content Server offers http streaming on port 8080 because port 80 is in use by other web services, such as the main page). If this fails, the player is unable to connect to server.
If an alternate port is configured for RTSP, the player will NOT re-try RTSP on the alternate port, even after negotiating available protocols during the MMS information exchange.
Note: MMS is not used for streaming transport for Windows Media Player version 9 and later. It is ONLY used for negotiating protocols.