Patent ID: 8239902
Filing Date: 2012-08-07
Classification: H04L

Abstract:
1. A method of providing at least one of a preview or replay function for a content on demand service provided by a service provider to a plurality of users, the method comprising: generating a first multicast stream of content for transmission to a user; generating one or more delayed multicast streams of content by passing the first multicast stream of content through at least one delay element in a serial chain of delay elements, each of the delayed multicast streams of content are derived from the first multicast stream of content and only differ therefrom in that the delayed multicast streams of content are each in advance of or after the first multicast stream of content by a respective time difference, wherein a first delayed multicast stream of content is derived by passing the first multicast stream of content through a delay element in the serial chain of delay elements simultaneously with a transmission of the first multicast stream of content to the user, and wherein each other delayed multicast stream of content is derived by passing a respective, previously delayed multicast stream of content through at least one additional, different delay element of the chain of delay elements farther down the serial chain of delay elements; transmitting the first multicast stream of content to the user using a first Internet Protocol (IP) address, wherein the user becomes a member of a first IP multicast group (IPMG); receiving a request from the user to view a preview or replay of a part of the content; and switching the user to one of the delayed multicast streams of content, wherein the user becomes a member of another IPMG, different from the first IPMG, which delayed multicast stream of content is at the time difference that matches the requested preview or replay part of the content, wherein each of the delayed multicast streams of content is transmitted to the user over a respective IP address, different from the first IP address, or over a respective port associated with the first IP address.