Apparatus and methods for moving cable modems between upstream channels

• US 8,201,207 B2
• Filed: 12/15/2008
• Issued: 06/12/2012
• Est. Priority Date: 12/15/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: An, James S., Sun, Hui, Li, De Fu, Brewer, Keil, Downey, John J., Leano, Chrisanto D.
• Primary Examiner(s): HOSSAIN, FARZANA E
• Application Number:
  US12/334,777
• Publication Number:
  US 20100154017A1
• Time in Patent Office: 1,275 Days
• Field of Search: 725/111, 370/225, 370/252, 370/397, 370/399, 375/219, 375/222, 709/223, 709/224
• US Class Current: 725/111
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/2865 Logical combinations
• CPC Class Codes: H04L 43/0817 by checking functioning
• CPC Class Codes: H04L 43/16 Threshold monitoring

Abstract

Disclosed are apparatus and methods for managing upstream channels on a per cable modem basis. In certain embodiments, one or more thresholds are defined for each of a plurality of upstream logical channels of a headend system for receiving data from a plurality of cable modems (or other types of access nodes). Each defined threshold corresponds to a measurable parameter of the corresponding upstream logical channel. One or more metrics are collected for each cable modem of each upstream logical channel. It is determined whether to downgrade a selected cable modem to a selected one of the logical channels that has a lower performance level than the selected cable modem'"'"'s current logical channel. Such downgrade determination is based on whether the selected cable modem'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds and whether a percentage of a total of the cable modems of such current logical channel that have failed a condition for the one or more defined thresholds is less than a predefined percentage level. The selected cable modem is then caused to move from the current logical channel to the selected logical channel when the percentage of the total cable modems that have failed is below a predefined level if such selected logical channel is available. Otherwise, the current logical channel'"'"'s modulation profile may be altered when the percentage of the total cable modems that have failed is above (or equal to) the predefined level.

Claims

1. A method comprising:

defining one or more thresholds for each of a plurality of upstream logical channels of a headend system for receiving data from a plurality of cable modems, wherein each defined threshold corresponds to a measurable parameter of the corresponding upstream logical channel;

collecting one or more metrics for each cable modem of each upstream logical channel;

determining whether to downgrade a selected cable modem to a selected one of the logical channels that has a lower performance level than the selected cable modem'"'"'s current logical channel,

wherein such downgrade determination is based on whether the selected cable modem'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds and whether a percentage of a total of the cable modems of such current logical channel that have failed a condition for the one or more defined thresholds is less than a predefined percentage level; and

causing the selected cable modem to move from the current logical channel to the selected logical channel when the percentage of the total cable modems is below a predefined level.

2. The method of claim 1, wherein determining whether to downgrade the selected cable modem comprises:

for each cable modem of the current logical channel, assessing whether such each cable modem'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds and placing such each cable modem on a downgrade candidate list when such each cable modem'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds; and

after each cable modem has been assessed, moving all of the cable modems that were placed on the downgrade candidate list to the selected logical channel when the cable modems that are on the downgrade candidate list constitute a percentage of the total cable modems of the current logical channel that is less than or equal to the predefined percentage level.

3. The method of claim 2, further comprising moving all of the cable modems of the current logical channel to the selected logical channel when the cable modems that are on the downgrade candidate list constitute a percentage of the total cable modems of the current logical channel that is greater than the predefined percentage level.

4. The method of claim 2, further comprising deferring a process for assessing whether to move all the cable modems of the current logical channel to the selected logical channel when the cable modems that are on the downgrade candidate list constitute a percentage of the total cable modems of the current logical channel that is less than or equal to the predefined percentage level.

5. The method of claim 2, further comprising:

for each cable modem that has been moved to the selected logical channel, determining whether to upgrade such each cable modem back to the current logical channel based on whether such each cable modem'"'"'s collected one or more metrics have met the condition of the one or more defined thresholds plus one or more corresponding hysteresis amounts; and

moving the each cable modem back to the current logical channel when it is determined that such each cable modem is to be upgraded.

6. The method of claim 5, further comprising:

periodically repeating the operations for determining whether to downgrade a each cable modem and determining whether to upgrade such each cable modem and moving such each cable modem when it is determined that such each cable modem is to be downgraded or upgraded;

tracking a count for each time a selected cable modem is downgraded or upgraded; and

inhibiting an upgrade move for a particular cable modem when the count for such particular cable modem exceeds a predefined number.

7. The method of claim 1, wherein each logical channel is a different physical channel.

8. The method of claim 1, wherein the logical channels are on a same physical channel.

9. The method of claim 1, wherein the logical channels have different modulation profiles that result in different transmission speeds.

10. The method of claim 1, wherein the predefined thresholds include one or more of the following thresholds for each cable modem:

a correctable forward error correction (FEC) ratio threshold, an uncorrectable FEC ratio threshold, and/or a signal to noise threshold.

11. The method of claim 1, wherein the selected logical channel has a lower performance level that is one or more levels lower than the current logical channel and the number of levels that the selected logical channel is lower depends on how much the selected cable modem'"'"'s collected metrics have failed the condition.

12. A system for facilitating communications in an access network, the access network including a plurality of nodes, the system comprising:

a headend in communication with at least a portion of the network nodes via a plurality of upstream logical channels having different modulation profiles;

the headend being further configured to perform the following operations;

defining one or more thresholds for each of the upstream logical channels, wherein each defined threshold corresponds to a measurable parameter of the corresponding upstream logical channel;

collecting one or more metrics for each node of each upstream logical channel;

determining whether to downgrade a selected node to a selected one of the logical channels that has a lower performance level than the selected node'"'"'s current logical channel, wherein such downgrade determination is based on whether the selected node'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds and whether a percentage of a total of the nodes of such current logical channel that have failed a condition for the one or more defined thresholds is less than a predefined percentage level; and

causing the selected node to move from the current logical channel to the selected logical channel when the percentage of the total nodes is below a predefined level.

13. The system of claim 12, wherein determining whether to downgrade the selected node comprises:

for each node of the current logical channel, assessing whether such each node'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds and placing such each node on a downgrade candidate list when such each node'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds; and

after each node has been assessed, moving all of the nodes that were placed on the downgrade candidate list to the selected logical channel when the nodes that are on the downgrade candidate list constitute a percentage of the total nodes of the current logical channel that is less than or equal to the predefined percentage level.

14. The system of claim 13, wherein the headend being is further configured to move all of the nodes of the current logical channel to the selected logical channel when the nodes that are on the downgrade candidate list constitute a percentage of the total nodes of the current logical channel that is greater than the predefined percentage level.

15. The system of claim 13, wherein the headend being is further configured to defer a process for assessing whether to move all the nodes of the current logical channel to the selected logical channel when the nodes that are on the downgrade candidate list constitute a percentage of the total nodes of the current logical channel that is less than or equal to the predefined percentage level.

16. The system of claim 13, further comprising:

for each node that has been moved to the selected logical channel, determining whether to upgrade such each node back to the current logical channel based on whether such each node'"'"'s collected one or more metrics have met the condition of the one or more defined thresholds plus one or more corresponding hysteresis amounts; and

moving the each node back to the current logical channel when it is determined that such each node is to be upgraded.

17. The system of claim 16, further comprising:

periodically repeating the operations for determining whether to downgrade a each node and determining whether to upgrade such each node and moving such each node when it is determined that such each node is to be downgraded or upgraded;

tracking a count for each time a selected node is downgraded or upgraded; and

inhibiting an upgrade move for a particular node when the count for such particular node exceeds a predefined number.

18. The system of claim 12, wherein each logical channel is a different physical channel.

19. The system of claim 12, wherein the logical channels are on a same physical channel.

20. The system of claim 12, wherein the logical channels have different modulation profiles that result in different transmission speeds.

21. The system of claim 12, wherein the predefined thresholds include one or more of the following thresholds for each node:

a correctable forward error correction (FEC) ratio threshold, an uncorrectable FEC ratio threshold, and/or a signal to noise threshold.

22. The system of claim 12, wherein the selected logical channel has a lower performance level that is one or more levels lower than the current logical channel and the number of levels that the selected logical channel is lower depends on how much the selected cable modem'"'"'s collected metrics have failed the condition.

23. At least one non-transitory computer readable storage medium having computer program instructions stored thereon that are arranged to perform the following operations:

defining one or more thresholds for each of a plurality of upstream logical channels for receiving data from a plurality of nodes, wherein each defined threshold corresponds to a measurable parameter of the corresponding upstream logical channel;

collecting one or more metrics for each node of each upstream logical channel;

determining whether to downgrade a selected node to a selected one of the logical channels that has a lower performance level than the selected node'"'"'s current logical channel, wherein such downgrade determination is based on whether the selected node'"'"'s collected one or more metrics have failed a condition of the one or more defined thresholds and whether a percentage of a total of the nodes of such current logical channel that have failed a condition for the one or more defined thresholds is less than a predefined percentage level; and

causing the selected node to move from the current logical channel to the selected logical channel when the percentage of the total nodes is below a predefined level.