Techniques for using a general query to circumvent specific query response failure in an IGMP system
View Patent ↗Flexibility of handling of multicast information using an Internet Group Management Protocol (IGMP) is improved by overcoming failures to respond to group specific queries. Such failures occur when heterogenous host devices are used on a common network. When a failure to respond to a group specific query is experienced, a general query is used to obtain information that was not provided by the group specific query.
1. 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.
2. The communications system according to claim 1 , wherein said DSLAM is configured to determine available bandwidth, and if bandwidth is available, continue providing the IGMP channel.
3. The communications system according to claim 2 , wherein said DSLAM is configured to determine available subscription bandwidth demand.
4. The communications system according to claim 1 , wherein each STB is configured to receive video data.
5. The communications system according to claim 1 , wherein said STBs are configured together as multicast group.
6. The communications system according to claim 1 , wherein said DSLAM is configured to generate a IGMP query at a user configurable frequency to determine if any STBs are still connected as a multicast group.
7. A method for providing Internet Group Management Protocol (IGMP) services, comprising:
receiving network data within a digital subscriber line access multiplexer (DSLAM) from a communications network;
delivering the network data to a plurality of set top boxes (STBs), each having an Internet Group Management Protocol (IGMP) host IP address, via an IGMP channel provided by the DSLAM to the STBs;
sending from the DSLAM a channel specific query over the IGMP channel to STBs listed as connected to the channel as listed on a network interface list of the DSLAM, and if each STB as listed on the network interface list responds, updating the network interface list;
if responses are not received from each STB listed as connected, sending a general query, and when each STB responds, updating the network interface list;
during a channel change request from a STB, dropping the IGMP channel when the network interface list indicates there are no other STBs connected to the IGMP channel, and if there is at least one STB still connected to the network port and IGMP channel, continue providing the IGMP channel; and
selectively controlling the DSLAM 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.
8. The method according to claim 7 , and further comprising determining available bandwidth, and if bandwidth is available, continue providing the IGMP channel.
9. The method according to claim 8 , wherein the determining available bandwidth comprises determining available subscription bandwidth demand.
10. The method according to claim 7 , and further comprising configuring the STBs together as a multicast group.
11. The method according to claim 7 , and further comprising generating an IGMP query at a user configurable frequency to determine if any STBs host devices are still connected as a multicast group.
12. A communications device, comprising:
a communications port configured to receive network data from a communications network;
a digital subscriber line access multiplexer (DSLAM) network port configured to connect to a plurality of set to boxes (STBs), each having an Internet Group Management Protocol (IGMP) host IP address, and provide an IGMP channel to the STBs over which network data is delivered;
a network interface list indicative of which STBs are joined to the IGMP channel;
wherein the DSLAM network port is configured to send a channel specific query over said IGMP channel to the STBs listed as connected to the IGMP channel, and if each STB responds, the network interface list is updated;
if responses are not received from each STB listed as connected, the DSLAM network port 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 DSLAM network port 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 network port is selectively controlled to send the general Query when the DSLAM network port determines a high likelihood that a STB will not manage properly a channel specific query.
13. The communications device according to claim 12 , wherein said DSLAM network port is configured to determine available bandwidth, and if bandwidth is available, continue providing the IGMP channel.
14. The communications device according to claim 13 , wherein said DSLAM network port is configured to determine available subscription bandwidth demand.
15. The communications device according to claim 12 , wherein each set top box is configured to receive video data.
16. The communications device according to claim 12 , wherein said DSLAM network port is configured to determine available subscription bandwidth demand.
17. The communications device according to claim 12 , wherein any STBs are configured together as multicast group.