Patent ID: 8874796

Claim:
A communications system, comprising: a plurality of set top boxes (STBs) each having an Internet Group Management Protocol (IGMP) host IP address; a digital subscriber line access multiplexer (DSLAM) configured to receive network data from a communications network and comprising, a network port connected to each of the STBs and configured to provide an IGMP channel to the STBs over which network data is delivered, and a network interface list indicative of which STBs are connected to the IGMP channel, wherein the DSLAM is configured to send a channel specific query over said IGMP channel to the STBs listed as connected to the channel, and if each STB as listed on the network interface list responds, the network interface list is updated, and if responses are not received from each STB listed as connected, the DSLAM is configured to send a general query and when each STB responds, the network interface list is updated, and wherein during a channel change request from a STB, the network device is configured to drop the IGMP channel when the updated network interface list indicates there are no other STBs connected to the IGMP channel and if there is still at least one STB connected to the network port and IGMP channel, continue providing the IGMP channel, and wherein the DSLAM is selectively controlled to send a general query when the DSLAM determines that there is at least a specified likelihood that a STB will not manage properly a channel specific query.