Sun Microsystems made an undisclosed investment last week in Kasenna, a Mountain View, Calif., startup that makes broadband infrastructure software for video-on-demand and the streaming of high-quality video and audio over the Web.

The companies also are working together on Sun's Media Appliance Platform, which uses Sun servers and storage devices to provide programming for video-on-demand, video networking, and interactive TV. Sun believes cable-TV providers play an important role in boosting consumer demand for interactive entertainment. Kasenna's latest product, built on its core technology for managing and distributing video and audio over IP and ATM networks, supports MPEG-4 files and back-office apps.