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Using a Multicast Protocol to Implement Video Switch for Video-On-Demand Based on Network Processor Architecture

IP.com Disclosure Number: IPCOM000129197D
Publication Date: 2005-Sep-30
Document File: 4 page(s) / 189K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for creating a video-on-demand server/switch, based on the network processor and multicast protocol of a CATV network infrastructure. Benefits include transmitting a clear video stream, and reducing the chance of unauthorized users viewing the stream.

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Using a Multicast Protocol to Implement Video Switch for Video-On-Demand Based on Network Processor Architecture

Disclosed is a method for creating a video-on-demand server/switch, based on the network processor and multicast protocol of a CATV network infrastructure. Benefits include transmitting a clear video stream, and reducing the chance of unauthorized users viewing the stream.

Background

In a traditional CATV network, the video-on-demand is realized by a scramble and descramble bit stream. The pay-per-view (PPV) video streams are scrambled and broadcasted to all the set top boxes through the cable network without discrimination. It is an individual set top box’s responsibility to block or play the video. For the authorized set top box, the smart card in the set top box is able to extract the keys from the control words which are transmitted with the video data in the bit stream. The keys are sent to the descrambler with the corresponding video data.  The descrambled video data is displayed by the video decoder. The disadvantage of this approach is that all users receive a scrambled video stream, even if they do not subscribe to the video program.  In this way, one could easily decode the scrambled video stream by using stolen keys from other video boxes.

General Description

The disclosed method creates a video-on-demand server/switch, based on the network processor and multicast protocol of a CATV network infrastructure. The following are the steps associated with the disclosed method:

1.      The disclosed method encapsulates the MPEG 2 video program stream in the IP packet.  Because the IP packet is easily transported through the CATV network and Ethernet, an IP routine algorithm is used to transport the MPEG 2 video stream (see Figure 1).

2.      The disclosed method associates a multicast group with a PPV program. The central video stream distribution station broadcasts the PPV program schedule including date, time, content brief description, and other related information in advance before the program is played. The IP packet carrying this program is assigned a multicast group ID, and each router in the network has the information about the program.

3.      The disclosed method joins the multicasting group by an individual set box user. When a program subscriber wants to order a PPV program, the application software inside the set top box system generates a join multicast group message and sends the message directly to the connected router. The multicast enabled routers along the upstream path add the set top box to the multicast group with a specific time, date, and program information.  Each router verifies if t...