Patent ID: 7676598
Filing Date: 2010-03-09
Classification: H04L

Abstract:
1. A method to control communications between a head-end system and a number of client systems through a network including a plurality of multicast router systems and receivers, the method comprising: forwarding, from each of the plurality of multicast router systems, multicast messages, the multicast messages being transmitted from the head-end system and addressed to respective multicast groups to select ones of the plurality of receivers enabled to accept, for a client system, messages addressed to any multicast group of which the receiver is a member, for each receiver, only a nearest one of the plurality of multicast router systems forwarding a copy of a message addressed to the multicast groups of which the receiver is a member directly to the receiver; maintaining subscriber group information linking each registered one of the number of client systems to an associated one of a plurality of subscriber groups; allocating registered client systems to at least one multicast group, such that all client systems associated with a particular subscriber group are in a common multicast group, a server in the head-end being arranged to multicast subscriber group messages to client systems in messages addressed to a multicast group, each subscriber group message being intended for all client systems in a subscriber group; obtaining information uniquely identifying the nearest multicast router system nearest to a receiver for a first client system; and assigning the first client system to a subscriber group including at least one further client system having the same nearest multicast router system.