Patent ID: 8416797
Filing Date: 2013-04-09
Classification: H04N

Abstract:
1. A method of operating a Reliable Transmission Protocol switch node to provide an IPTV multicast, the method comprising: receiving encrypted IP packets transporting an encrypted media stream from an IPTV Head-end, the encrypted media stream containing complete image frames; receiving unencrypted identifiers identifying encrypted packets containing complete image frame data; storing the received encrypted packets in a buffer; on receipt of a request from a media renderer to provide the IPTV multicast, sending the encrypted packet(s) containing the last complete image frame in the encrypted media stream and all subsequent encrypted packets to the media renderer; wherein encrypted packets containing complete image frames are accorded a different Class of Service value to packets not containing complete image frames, the Class of Service value included in the packet header and identifying which packets relate to complete image frames.