About multicast information files

Updated: October 4, 2007

Applies To: Windows Server 2008, Windows Server 2008 R2

The Multicast Announcement Wizard creates both an announcement file and a multicast information file. The multicast information file is a Windows Media metafile with an .nsc extension. The multicast information file contains information a player needs to decode a stream. Before receiving content delivered as a multicast stream, the player must access the multicast information file to extract the following information:

  • Multicast IP address

  • Multicast port

  • Time-to-live

  • Default error correction span

  • Multicast logging URL

  • Unicast rollover

  • Stream formats used by the content being delivered

If you make any changes to the publishing point configuration, such as modifying settings for the WMS Multicast Data Writer plug-in or renaming the publishing point, you must use the Multicast Announcement Wizard to create a new multicast information file so that players will be able to connect to your content.


Multicast information files must include all the stream formats used by your content. If the stream formats are not listed in the multicast information file, clients cannot access the multicast stream.
Multicast streaming and the WMS Multicast Data Writer plug-in are not available if Windows Media Services is installed on some Windows Server 2008 and Windows Server 2008 R2 operating systems. For more information, see Decide which version of Windows Server is right for you.