METHOD FOR MANAGING DELIVERY OF MULTICAST TRAFFIC TO DEVICES

Abstract

Multicast management messages associate a channel with one or more multicast groups. The information included in the multicast management messages are combined into a channel association table that may be stored at a CPE device for each of one or more interfaces. The channel association table is used in response to a request for a desired multicast group to select a channel over which the desired multicast group should be delivered. The channel selection is based on a review of the channel association table. If a channel is associated with the desired group, it is selected. If a channel is not associated with the desired group, a channel is selected from a plurality of available channels based on group traffic loading criteria. A multicast message, such as a JOIN, is forwarded to other devices informing them that the desired group should only be sought and/or delivered on the selected channel.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates duplication of a multicast group over multiple channels serving multiple CPE devices.

FIG. 2 illustrates transmission of a multicast group over a channel serving multiple CPE devices.

FIG. 3 updating a channel association table that associates one or more channels with multicast groups that they carry.

FIG. 4 illustrates a flow diagram for using an updated association table to issue a multicast join message for a desired group on a selected channel.

DETAILED DESCRIPTION

As a preliminary matter, it will be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many methods, embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the following description thereof, without departing from the substance or scope of the present invention.

Accordingly, while the present invention has been described herein in detail in relation to preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purposes of providing a full and enabling disclosure of the invention. The following disclosure is not intended nor is to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.

Turning now to the figures, FIG. 3 illustrates a method 300 for updating a channel association table corresponding to a CPE. Multicast management message snooping may be used, or other similar method known to those skilled in the art of updating an information set based on periodic or occasional information messaging on a network. Method 300 starts at step 305 and a first multicast management message is received at step 310. The first multicast management message may be an Internet Group Management Protocol (“IGMP”) message sent periodically or occasionally from a central device, such as a router or CMTS to which the one or more CPE devices are coupled. It will be appreciated that when used in a CPE device having multiple interfaces (an interface including corresponding tuner circuitry, for example), for tuning to multiple channels simultaneously, method 300 may be performed at the CPE for each interface separately. Thus, it will be appreciated that for purposes of clarity, method 300 is described herein with respect to one interface. However, a CPE typically has a single channel association table corresponding to it that includes associations for all interfaces.

Information delivered in the first multicast management message may include a listing of multicast groups available at the receiving interface. At step 315, the information included in the first multicast management message received at step 310 may be used to update existing channel association table information. The channel association table may be stored at the given CPE device which includes the interface for which method 300 is being performed. All of the channels over which a particular multicast group is available are associated with the particular multicast group in the channel association table, an example of which is shown as table 8 in FIGS. 1 and 2.

Continuing with the description of FIG. 3, after the channel association table has been updated with channels over which given multicast groups are available, the table is further analyzed at step 320. At step 320, channel associations that may have been made during previous iterations of method 300 are compared to the information contained in the most recent multicast management message received at step 305. Channel associations that are present in the association table, but that are not included in the most recent first multicast management message are removed from the channel association table at step 320. After the association table has been updated at steps 310 and 320, method 300 returns to the beginning of the method and waits to receive another first multicast management message at step 310. Thus, for each interface, or tuner circuitry, at a given CPE device, a channel association table is routinely updated (may be periodic, as-requested, as needed due to new channel associations at the central device, etc.) so that a channel carrying a desired multicast group can be determined by the CPE device. It will be appreciated that a user device, such as, for example, a set top box, a PC or other user device that may receive multimedia content, including music and video, over IP, may typically request a given multicast group based on a channel guide that is periodically delivered to such user devices.

Turning now to FIG. 4, a method for using an updated channel association table to issue a second multicast management message, such as a multicast JOIN message, from a particular given CPE for a desired group on a selected channel is illustrated. Method 400 starts at step 405. An evaluation of the channel association table described in reference to FIGS. 1, 2 and 3 is made at step 410 in response to a request from a user device to receive a desired multicast group. After evaluating the channel association table at step 410, a determination is made at step 415 whether the desired multicast group is available on any channel, whether to the given CPE device, or any other CPE devices that are coupled to the same central device via one or more of the same interfaces as the given CPE device in connection with which the evaluation was performed.

As discussed above in reference to other figures, more than one channel may be associated with a given multicast group. Even if more than one channel is associated with a desired multicast group, method 400 advances from step 415 as soon as a channel is determined to be associated with the desired multicast channel. Thus, the first channel encountered during the determination at step 415 is selected at step 420 as the channel that should be used to receive the desired multicast group.

At step 425, a second multicast management message, such as an IGMP JOIN message is sent from the given CPE device that serves the user device making the group request. The second multicast management message/JOIN message is sent from the CPE to the communication network, typically an HFC or Ethernet network, to which other network devices, such as other CPE devices having other user devices coupled thereto, are coupled. Other network devices may then use the information contained in the JOIN message when attempting to receive the same desired multicast group. In other words, if a device coupled to CPE A sends a request message for a desired multicast group, CPE A performs steps 410-420, determines that the desired group is available to it on channel C3 and forwards a JOIN message to the network that any other CPE device coupled to a user device requesting the same desired group should use channel C3 to receive the same desired group. When the multicast JOIN message is sent at step 425 for the desired group to be delivered over the selected channel, channel association tables of other devices are updated so that only the selected channel is associated with the desired group. Thus, multiple channel associations with a particular multicast group are reduced, or eliminated.

Returning to the determination at step 415, if the results of the review of the channel association table performed at step 410 do not indicate that there is a current channel available to the requesting CPE/user device, then method 400 advances to step 430. At step 430, a review of the channels that are available at the requesting given CPE is performed and the currently available channel—to which the requesting CPE may or may not be tuned—currently carrying the least number of multicast groups is selected. This lowest-loaded channel is associated with the desired multicast group in the channel association table corresponding to the given CPE device at step 435. Then, a multicast JOIN is sent into the network instructing that the desired multicast group be made available on the selected channel at step 425 as described above. Method 400 ends at step 440.

Thus, method 400 provides for selecting a channel over which a desired multicast group should be carried, and based on updated channel association table information, instructs network devices, including a CMTS, that only one channel should be used to deliver a given desired multicast group to a plurality of CPE devices that can access the same channels.

These and many other objects and advantages will be readily apparent to one skilled in the art from the foregoing specification when read in conjunction with the appended drawings. It is to be understood that the embodiments herein illustrated are examples only, and that the scope of the invention is to be defined solely by the claims when accorded a full range of equivalents.

Claims

1. A method for minimizing the number of channels making available a multicast group to a plurality of CPE devices, comprising: receiving a first multicast management message that includes information that associates each of a plurality of multicast groups with a channel that can deliver the each of the plurality of multicast groups;associating all channels that are associated with each of the plurality of multicast groups in the first multicast management message with their corresponding multicast groups or groups in a channel association table; andremoving previously associated channel associations with a corresponding multicast group, or groups, from the channel association table that are not included in the first multicast management message.

2. The method of claim 1 further comprising: evaluating the channel association table;determining whether a desired multicast group is available on a channel that can be accessed by a given CPE device based on the evaluation of the channel association table;selecting a channel from the channel association table that is associated with the desired multicast group; andproviding a second multicast management message to a network to which the given CPE is coupled, the second multicast management message including instruction that the desired multicast group should only be delivered on the selected channel to all CPE devices coupled to a central device to which the given CPE device is coupled.

3. The method of claim 1 further comprising: evaluating the channel association table;determining whether a desired multicast group is available on a channel that can be accessed by a given CPE device based on the evaluation of the channel association table;selecting a channel that is associated with the fewest number of multicast groups if the desired multicast group is not associated with any of the channels that the given CPE can access based on the evaluation of the channel association table;associating the selected channel with the desired multicast group in the channel association table; andproviding a second multicast management message to a network to which the given CPE is coupled, the second multicast management message including instruction that the desired multicast group should only be delivered on the selected channel to all CPE devices coupled to a central device to which the given CPE device is coupled.

4. The method of claim 2 wherein the central device is a CMTS.

5. The method of claim 3 wherein the central device is a router.

6. The method of claim 2 wherein the second multicast management message is a multicast JOIN message.

7. The method of claim 3 wherein the second multicast management message is a multicast JOIN message.

8. The method of claim 1 wherein the first multicast management message is an IGMP message.

9. The method of claim 1 wherein one or more of the CPE devices includes multiple interfaces for interfacing with different channels.

10. The method of claim 9 wherein a separate channel association table corresponds to each interface.

11. The method of claim 9 wherein an interface includes tuner circuitry.

12. A method for minimizing the number of channels making available a multicast group to a plurality of CPE devices, comprising: receiving a first multicast management message that includes information that associates each of a plurality of multicast groups with a channel that can deliver the each of the plurality of multicast groups;associating all channels that are associated with each of the plurality of multicast groups in the first multicast management message with their corresponding multicast groups or groups in a channel association table;removing previously associated channel associations with a corresponding multicast group, or groups, from the channel association table that are not included in the first multicast management message;evaluating the channel association table;determining whether a desired multicast group is available on a channel that can be accessed by a given CPE device based on the evaluation of the channel association table;selecting a channel from the channel association table that is associated with the desired multicast group; andproviding a second multicast management message to a network to which the given CPE is coupled, the second multicast management message including instruction that the desired multicast group should only be delivered on the selected channel to all CPE devices coupled to a central device to which the given CPE device is coupled.

13. A method for minimizing the number of channels making available a multicast group to a plurality of CPE devices, comprising: receiving a first multicast management message that includes information that associates each of a plurality of multicast groups with a channel that can deliver the each of the plurality of multicast groups;associating all channels that are associated with each of the plurality of multicast groups in the first multicast management message with their corresponding multicast groups or groups in a channel association table;removing previously associated channel associations with a corresponding multicast group, or groups, from the channel association table that are not included in the first multicast management message;evaluating the channel association table;determining whether a desired multicast group is available on a channel that can be accessed by a given CPE device based on the evaluation of the channel association table;selecting a channel that is associated with the fewest number of multicast groups if the desired multicast group is not associated with any of the channels that the given CPE can access based on the evaluation of the channel association table;associating the selected channel with the desired multicast group in the channel association table; andproviding a second multicast management message to a network to which the given CPE is coupled, the second multicast management message including instruction that the desired multicast group should only be delivered on the selected channel, to all CPE devices coupled to a central device to which the given CPE device is coupled.

14. A method for minimizing the number of channels making available a multicast group to a plurality of CPE devices coupled to a central device, comprising: generating a first multicast management message that includes information that associates each of a plurality of multicast groups with a channel that can deliver the each of the plurality of multicast groups;associating all channels that are associated with each of the plurality of multicast groups in the first multicast management message with their corresponding multicast groups or groups in a channel association table;removing previously associated channel associations with a corresponding multicast group, or groups, from the channel association table that are not included in the first multicast management message;selecting a channel to deliver a desired multicast group to the CPE devices from the central device; andaltering routing configuration at the central device based on the selected channel so that the desired multicast group is provided from the central device only over the selected channel.

15. The method of claim 14 wherein the central device is a CMTS.

16. The method of claim 14 wherein the central device is a router.

17. The method of claim 16 wherein the router is an internet protocol router.

18. The method of claim 15 wherein altering routing configuration includes switching routing paths between an input and an output port, to which the CPE devices are coupled, so that the desired multicast group is made available from the central device to the CPE devices over only the selected channel.

19. The method of claim 16 wherein altering routing configuration includes updating routing tables and address information so that the desired multicast group is made available from the central device to the CPE devices over only the selected channel.