Upstream ranging in communications devices

1. A computer-implemented method, comprising:

identifying a downstream channel at a customer premise equipment device;

receiving a list of upstream channels from a headend system on said downstream channel identified by the customer premise equipment device;

randomizing said list of upstream channels at the customer premise equipment device;

sorting the randomized list of upstream channels at the customer premise equipment device;

creating a hierarchical candidate list at the customer premise equipment device based on said sorted list of upstream channels and one or more predefined channels comprising upstream channels not included in the list of upstream channels received from the headend system; and

performing ranging on upstream channels at the customer premise equipment device in an order defined by the hierarchical candidate list until successfully ranging on one of the upstream channels.

2. The computer-implemented method of claim 1 , wherein the sorting of said list of upstream channels is based on channel size.

3. The computer-implemented method of claim 1 , wherein ranging is performed on an upstream communication path based on asynchronous time division multiplexing.

4. The computer-implemented method of claim 3 , wherein receiving the list of upstream channels on said downstream channel is provided by a MAC domain descriptor in a DOCSIS based communication system.

5. The computer-implementation method of claim 1 , further comprising:

receiving one or more upstream channel descriptors over a collection period on said downstream channel;

removing upstream channels from said hierarchical candidate list if said upstream channels are not observed over said collection period; and

appending any remaining observed upstream channels, if existing, at the end of said hierarchical list, prior to attempting ranging.

6. The computer-implemented method of claim 5 , further comprising sorting the remaining observed upstream channels is performed prior to appending to said hierarchical list.

7. The computer-implemented method of claim 6 , wherein the sorting of the remaining observed upstream channels is based on channel size.

8. The computer-implementation method of claim 1 , further comprising:

receiving one or more upstream channel descriptors over a collection period on said downstream channel;

moving ahead upstream channels within said hierarchical candidate list if said upstream channels are observed over said collection period; and

appending any remaining observed upstream channels not on the hierarchical candidate list, if existing, at the end of said hierarchical candidate list, prior to attempting ranging.

9. The computer-implemented method of claim 8 , further comprising sorting the remaining observed upstream channels prior to appending to said hierarchical list.

10. The computer-implemented method of claim 9 , wherein the sorting of the remaining upstream channels is based on channel size.

11. The computer-implementation method of claim 1 , further comprising:

receiving one or more upstream channel descriptors over a collection period on said downstream channel; and

appending said one or more observed upstream channels at the end of the said hierarchical list if they are not part of said hierarchical list, prior to attempting ranging.

12. The computer-implemented method of claim 11 , further comprising sorting the one or more observed upstream channels prior to appending to said hierarchical list.

13. The computer-implemented method of claim 12 , wherein the sorting of said one or more observed upstream channels is based on channel size.

14. One or more non-transitory computer-readable media having instructions stored thereon, the one or more computer readable media, when executed by a processor, cause the processor to perform operations comprising:

identifying a downstream channel;

receiving a list of upstream channels on said downstream channel;

randomizing said list of upstream channels;

sorting the randomized list of upstream channels based on channel size;

creating a hierarchical candidate list by appending said sorted list of upstream channels after one or more predefined channels comprising both channels not included on the received list of upstream channels and channels included on the received list of upstream channels; and

performing ranging on the upstream channels in an order defined by the hierarchical candidate list until successfully ranging on one of the upstream channels.

15. The one or more computer-readable media of claim 14 , wherein receiving the list of upstream channels on said downstream channel comprises receiving a MAC domain descriptor in a DOCSIS based communication system and parsing the MAC domain descriptor.

16. The one or more computer-readable media of claim 14 , further comprising:

receiving one or more upstream channel descriptors over a collection period on said downstream channel;

removing upstream channels from said hierarchical candidate list if said upstream channels are not observed over said collection period;

sorting the remaining observed upstream channels, if existing, based on channel size; and

appending any remaining observed upstream channels at the end of said hierarchical list, prior to attempting ranging.

17. The one or more computer-readable media of claim 14 , further comprising:

receiving one or more upstream channel descriptors over a collection period on said downstream channel; and

moving ahead any upstream channels within said hierarchical candidate list if said upstream channels are observed over said collection period;

sorting any remaining observed upstream channels based on channel size; and

appending any sorted remaining observed upstream channels at the end of said hierarchical list, prior to attempting ranging.

18. The one or more computer-readable media of claim 14 , further comprising:

receiving one or more upstream channel descriptors over a collection period on said downstream channel;

sorting any the upstream channel frequencies observed in the upstream channel descriptors and not included in the hierarchical candidate list based on channel size; and

appending the sorted observed upstream channels at the end of the said hierarchical list prior to attempting ranging.

19. A system, comprising:

input/output circuitry and a processor operable to identify a downstream channel and receive a list of upstream channels on said downstream channel;

a data store operable to store computer program instructions and temporary storage for said processor;

a processor operable execute said computer program instructions, the computer program instructions being operable to cause the processor to:

randomize said list of upstream channels;

sort said randomized list of upstream channels;

generate a hierarchical candidate list by appending said sorted list of upstream channels after one or more predefined channels comprising channels not included on said list of upstream channels; and

perform ranging on the upstream channels in conjunction with the input/output circuitry, the ranging being performed in an order defined by the hierarchical candidate list until successfully ranging on one of the upstream channels.

20. The system of claim 19 , wherein said computer program instructions are further operable to cause the processor to sort said list of upstream channels based on channel size.

21. The system of claim 19 , wherein the computer program instructions are further operable to cause the processor to perform ranging on an upstream communication path in conjunction with the input/output circuitry based on asynchronous time division multiplexing.

22. The system of claim 21 , wherein the list of upstream channels received on said downstream channel is received via a MAC domain descriptor in a DOCSIS based communication system.

23. The system of claim 19 , wherein the computer program instructions are further operable to cause the processor to:

receive one or more upstream channel descriptors over a collection period on said downstream channel via the input/output circuitry; and

remove upstream channels from said hierarchical candidate list if said upstream channels are not observed over said collection period;

sort any remaining observed channels based on channel size; and

append any sorted remaining channels at the end of said hierarchical list prior to attempting ranging.

24. The system of claim 19 , wherein the computer program instructions are further operable to cause the processor to:

receive one or more upstream channel descriptors over a collection period on said downstream channel via the input/output circuitry; and

move ahead upstream channels received in said list of upstream channels from said hierarchical candidate list if said upstream channels are observed in the one or more upstream channel descriptors over said collection period;

sort any remaining observed channels based on channel size; and

append any remaining observed channels at the end of said hierarchical list, prior to attempting ranging.

25. The system of claim 19 , wherein the computer program instructions are further operable to cause the processor to:

receive one or more upstream channel descriptors over a collection period on said downstream channel via the input/output circuitry; and

sort one or more upstream channels observed from the one or more upstream channel descriptors based on channel size; and

append the sorted upstream channels observed from the one or more upstream channel descriptors at the end of the said hierarchical list if they are not part of said hierarchical list prior to attempting ranging.