Options for playing multicast video on a web page

Assuming a network开发者_JAVA技巧 hierarchy that supports video multicasting, what options are there today to tap into this stream from a web page?

I've seen some references to this with Silverlight and project Star Light, which I unfortunately have no experience with. It also feels like a third option behind HTML5 and Flash.

What is out there on the market today that can handle this?

Qumu offers Multicast video for Silverlight today. Silverlight 4 (released in the first half of 2010) will have enhanced abilities for multicast as well.