DW-TV Live Stream Utilizes Peer-To-Peer Technology | Receiving Deutsche Welle′s TV programming in your area | DW | 10.04.2006
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DW-TV Live Stream Utilizes Peer-To-Peer Technology

Larger image, higher resolution: DW-TV's program is now available in an optimized version on the Deutsche Welle Web site, DW-WORLD.DE.


This technological advance has been made possible through a cooperation with the Danish company Octoshape ApS. The company was founded in 2003 by Stephen Alstrup and Theis Rauhe. Their team has developed technology that makes it possible to stream audio and video content more effectively on the Internet, resulting in a higher-quality live stream program for DW-TV. All you need is a plug-in, a broad band Internet connection, and a Java application installed on your computer.

The Octoshape Technology is based on a peer-to-peer (or "P2P") streaming network, a so-called grid casting and data splitting. This will enable the user to receive a better image with little additional effort. Here's an explanation of the three ways in which this new technology works:

P2P networks became popular through data exchange sites like the Internet music services Napster and KaZaA. The advantage of a P2P network is that data transfer can take place on all connected computers. The differentiation between sending and receiving computers is thereby obsolete: Every computer that receives can also send information -- as long as there is free capacity, which is most often the case. The content to be streamed is therefore no longer stored on one host computer that can become overloaded when a large number of requests from the Internet come at once, nor is it kept on a number of sub-servers, which may be spread across the world, but do not prevent "bottlenecking" from occurring.

In grid casting, the connection between computers is different than with P2P streaming. The latter uses a tree-structure, so that a signal can only be received from a single computer in the tree structure at a time. In a grid, every computer is a unit that is hierarchically equal to the other computers, which means that a signal can be received from a number of computers on the grid simultaneously. In this way, there are fewer bottlenecks to be expected during data reception, since the data burden is being carried by a number of shoulders (i.e., computers in the grid).

Now the signal just has to reach the users of DW-TV as a live stream without any disturbances. Octoshape achieves this by splitting the stream into smaller, identical data streams, for example from a bulky 400 kbit/s package into 12 smaller groups of 100kbit/s. Of these twelve streams, only four must reach the user. The signal also includes additional mega data -- a stand-by list and an address book. This ensures that fallouts in the data stream are counter-balanced, because a "back-up supplier" can replace the missing data.

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