Delivering a multicast stream

Applies To: Windows Server 2008, Windows Server 2008 R2

Application Protocol Protocol Port IP Address Range



1-65535 (Out) to (IPv4)

FF00:0000:0000:0000:0000:0000:0000:0000 to FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF (IPv6)

When you deliver content as a multicast stream, network traffic is directed through one of the class D IP addresses. Multicast IP addresses are class D addresses that fall within two ranges: to and FF00:0000:0000:0000:0000:0000:0000:0000 to FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF. The addresses in the first range are Internet Protocol version 4 (IPv4) addresses, while the addresses in the second range are IPv6 addresses.

Multicast streaming typically will not work over the Internet because forwarding of multicast IP packets is not enabled on routers on the Internet. For intranet use, it is recommended that you use IPv4 addresses in the range 239.*.*.*. The routers on the network over which you are transmitting your content must be multicast-enabled, meaning that they must be able to interpret class D addresses or they will not be able to forward your multicast information to clients.

IPv6 is designed to accommodate increasing demand for unique IP addresses. IPv6 increases the IP address size from 32 bits to 128 bits to support more levels of addressing hierarchy and a greater number of addressable nodes. Not all networks are configured to use IPv6, but Windows Media Services will automatically use IPv6 when it is available.

For multicast streams, you can specify the IP address and port values in the WMS Multicast Data Writer plug-in properties for your broadcast publishing point. To access these properties, do the following in Windows Media Services Administrator:

  1. In the console tree, click the broadcast publishing point from which you want to multicast content. If the publishing point is started, click Stop.

  2. In the details pane, click the Properties tab.

  3. In Category, click Multicast streaming.

  4. In Plug-in, click WMS Multicast Data Writer, and then click Properties.


Multicast streaming and the WMS Multicast Data Writer plug-in are not available on certain versions or editions of the Windows Server operating system. For more information, see Decide which version of Windows Server is right for you.