Broadcast Client Architecture

[This is preliminary documentation and subject to change.]

The architecture of the broadcast client enables computers based on the Microsoft® Windows® 98 operating system to be client systems for many types of broadcast network. The broadcast client is a standard computer enhanced with hardware and software components that enable it to process video, audio, and data from a variety of sources.

Some networks that broadcast clients can support include:

• The Internet's multicast backbone (MBONE), and the networks and telephone lines that support it — Integrated Services Digital Network (ISDN), Ethernet, Asymmetrical Digital Subscriber Line (ADSL), and others.
• Cable television networks, such as Comcast and Tele-Communications, Inc. (TCI).
• Wireless cable networks.
• Conventional television networks.
• Television networks that broadcast digital data to viewers in the vertical blanking interval (VBI) of the television signal, such as Intel Intercast.

Some networks used by Broadcast Architecture send information as one-way data streams. Such networks have several unique aspects that must be considered. These networks cannot run server applications that require a back channel to receive data from the client. In other circumstances, the architecture of the broadcast client allows the use of another network, such as the Internet, to provide this back channel. Another effect of the one-way nature of such networks is that the client cannot request that a bad packet be resent. To reduce the problems this inability causes, the server must periodically resend data so the client can replace any corrupted or lost data. Finally, one-way broadcast networks are capable of very high data transfer rates. Devices for Broadcast Architecture networks, and the software associated with these devices, must be capable of handling this data rate without burdening the CPU.

The high bandwidth of many broadcast networks make them ideal for transmission of audio and video data as well as computing data. Broadcast Architecture uses a set of modular components to receive, process, and present this data. This modular design means application developers can create applications without regard for the underlying technology. Hardware vendors can provide drivers to make their devices compatible with other broadcast client components.