Front-end structure for access network line card

• US 7,840,988 B1
• Filed: 05/07/2004
• Issued: 11/23/2010
• Est. Priority Date: 05/07/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Zhou, Jiahuai
• Primary Examiner(s): Koenig; Andrew Y
• Assistant Examiner(s): Castro; Alfonso
• Application Number:
  US10/840,884
• Time in Patent Office: 2,391 Days
• Field of Search: 725/95, 725105-128, 725/148, 725/149, 348/192, 370/217, 370/221, 370/219, 714/4
• US Class Current: 725/114
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/239 Interfacing the upstream path of the transmission network, e.g. prioritizing client content requests hybrid fiber coaxial [HFC] networks for upstream channel allocation for video distribution H04L12/2801; flow control in data networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2405 Monitoring of the internal components or processes of the server, e.g. server load allocation of resources in multiprogramming arrangements G06F9/50; performance measurement of computer activity G06F11/34
• CPC Class Codes: H04N 21/2408 Monitoring of the upstream path of the transmission network, e.g. client requests monitoring data switching networks utilization H04L43/0876; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem

Abstract

A technique is described for facilitating communication in access networks such as cable networks. One aspect of the present invention is directed to an improved line card configuration which may be used to provide upstream channel “high availability” protection whereby the cable modems of a failed upstream channel may be immediately and dynamically reassigned to an alternate upstream channel in order to minimize service disruption. Another aspect of the present invention is directed to an improved line card configuration which is able to provide load balancing capabilities across multiple upstream channels associated with one or more line cards. According to a specific implementation, such load balancing capabilities may be used to reassign cable modems (which are physically connected to a fixed upstream port) to alternate upstream channels. Yet another aspect of the present invention is directed to an improved line card configuration which is able to provide the feature of virtual cabling. According to one embodiment, the feature of virtual cabling may be used to dynamically configure, via software, cable modems from any selected subscriber group to “talk” to any desired PHY chip on any line card within a CMTS.

Claims

1. A system, comprising:

at least one access control system including at least one cable modem termination system (CMTS) operable to communicate with a first plurality of nodes of a first subscriber group via a first shared access upstream channel, and operable to communicate with second plurality of nodes of a second subscriber group via a second shared access upstream channel, wherein the first and second plurality of nodes are cable modems;

the access control system comprising;

a CMTS line card including a first plurality of physical (PHY) layer components, the first plurality of physical layer components including a first upstream port and a first PHY processor, the first upstream port being associated with a first upstream channel, wherein the first plurality of nodes are physically coupled to the first upstream port;

wherein the CMTS line card further includes a second plurality of physical layer components, the second plurality of physical layer components including a second upstream port and a second PHY processor, the second upstream port being associated with a second upstream channel, wherein the second plurality of nodes are physically coupled to the second upstream port;

the access control system being operable to;

configure at least a portion of the first plurality of physical layer components to cause upstream signals from the first plurality of nodes coupled to the first upstream port to be processed by the first PHY processor;

configure at least a portion of the second plurality of physical layer components to cause upstream signals from the second plurality of nodes coupled to the second upstream port to be processed by the second PHY processor, wherein at least a portion of the second plurality of PHY layer components are coupled to at least a portion of the first plurality of PHY layer components via one or more physical components;

process upstream signals from a first portion of the first plurality of nodes at the first PHY processor;

process upstream signals from a second portion of the second plurality of nodes at the second PHY processor;

detect a first event or condition for triggering a dynamic re-configuration of at least one port-PHY processor configuration;

dynamically configure, in response to detecting the first event or condition, at least a portion of the first plurality of physical layer components to cause upstream signals received from the first portion of the first plurality of nodes via the first upstream port to be processed by the second PHY processor, thereby enabling the upstream signals sent from the first portion of the plurality of nodes coupled to the first upstream port associated with the first upstream channel to be processed by the second PHY processor associated with the second upstream channel; and

process, in response to the dynamic configuration, upstream signals from the first portion of the first plurality of nodes at the second PHY processor.

2. The system of claim 1:

wherein the first plurality of physical layer components includes a third upstream port, the third upstream port being associated with a third upstream channel;

the access control system being operable to;

configure at least a portion of the first plurality of physical layer components to cause upstream signals received from a third portion of the first plurality of nodes via the third upstream port to be processed by the first PHY processor;

process the upstream signals received from the third portion of the first plurality of nodes at the first PHY processor concurrently while the upstream signals received from the first portion of the first plurality of nodes are processed by the second PHY processor.

3. The system of claim 1:

wherein the first plurality of physical layer components includes a first splitter operable to communicatively couple the first upstream port to the first PHY processor and the second PHY processor; and

wherein the second plurality of physical layer components includes a second splitter operable to communicatively couple the first upstream port to the first PHY processor and the second PHY processor.

4. The system of claim 1 wherein the first event or condition relates to a bandwidth resource issue at the first upstream channel.

5. The system of claim 1 wherein the first event or condition relates to an upstream channel load balancing operation implemented at the access control system.

6. The system of claim 1 wherein the first event or condition relates to a failure detected in connection with the first upstream channel.

7. The system of claim 1, wherein the first plurality of physical layer components includes a third upstream port, the third upstream port being associated with a third upstream channel;

the access control system being operable to;

detect a bandwidth related issue at the first upstream channel;

identify, in response to detecting the bandwidth related issue, at least one alternate upstream channel to be used for performing load balancing on the first upstream channel and the at least one alternate upstream channel;

initiate, in response to detecting the bandwidth related issue, at least one load balancing operation for balancing bandwidth loads across selected upstream channels including the first and second upstream channels;

configure at least a portion of the first plurality of physical layer components to cause upstream signals received from a third portion of the first plurality of nodes via the third upstream port to be processed by the first PHY processor; and

process upstream signals from the third portion of the first plurality of nodes at the first PHY processor concurrently while upstream signals from the first portion of the first plurality of nodes are processed by the second PHY processor.

8. The system of claim 1, wherein the first event or condition relates to an issue or problem associated with the first upstream channel, the access control system being further operable to:

identify a first selected portion of nodes registered to utilize the first upstream channel for communications with the access control system;

identify, in response to detecting the first event or condition, at least one alternate upstream channel to be used by the first selected portion of nodes for upstream communications with the access control system; and

instruct the first selected portion of nodes to suspend upstream transmissions on first upstream channel.

9. The system of claim 1, wherein the first event or condition relates to an issue or problem associated with the first upstream channel, the access control system being further operable to:

identify a first selected portion of nodes registered to utilize the first upstream channel for communications with the access control system;

identify, in response to detecting the first event or condition, at least one alternate upstream channel to be used by the first selected portion of nodes for upstream communications with the access control system;

dynamically cause, in response to detecting the first event or condition, upstream transmissions on the first upstream channel to be temporarily suspended during a first time interval; and

dynamically cause, in response to detecting the first event or condition, upstream transmissions on the at least one alternate upstream channel to be temporarily suspended during the first time interval.

10. The system of claim 1, wherein the first event or condition relates to an issue or problem associated with the first upstream channel, the access control system being further operable to:

identify a first selected portion of nodes registered to utilize the first upstream channel for communications with the access control system;

identify, in response to detecting the first event or condition, a first alternate upstream channel to be used by the first selected portion of nodes for upstream communications with the access control system, wherein the access control system is operable to receive, at a third upstream port, upstream communications transmitted on the first alternate upstream channel;

dynamically cause, in response to detecting the first event or condition, upstream transmissions on the first upstream channel to be temporarily suspended during a first time interval;

dynamically cause, in response to detecting the first event or condition, upstream transmissions on the at least one alternate upstream channel to be temporarily suspended during the first time interval;

dynamically configure, in response to detecting the first event or condition, the third upstream port to communicate with a selected PHY processor;

dynamically cause the first selected portion of nodes to utilize the first alternate upstream channel for communicating with the access control system; and

dynamically cause, upstream transmissions on the first upstream channel and first alternate upstream channel to be resumed.

11. The system of claim 1 being further operable to:

identify duplicate upstream channel signals received at the first upstream port and second upstream port;

selectively identify a first portion of the duplicate upstream channel signals to processed by the access control system; and

selectively identify a second portion of the duplicate upstream channel signals which are to be ignored.

12. The system of claim 1, wherein the one or more physical components include one or more switches.

13. The system of claim 1, wherein each upstream channel of the at least one CMTS is associated with a respective upstream port and a respective set of PHY layer components.

14. A system, comprising:

at least one access control system operable to communicate with a first plurality of nodes of a first subscriber group via a first shared access upstream channel, and operable to communicate with second plurality of nodes of a second subscriber group via a second shared access upstream channel;

the access control system comprising;

a cable modem termination system (CMTS) line card including a first plurality of physical (PHY) layer components, the first plurality of physical layer components including a first upstream port and a first PHY processor, the first upstream port being associated with a first upstream channel, wherein upstream signals from the first plurality of nodes are received via the first upstream port;

wherein the CMTS line card further includes a second plurality of physical layer components, the second plurality of physical layer components including a second upstream port and a second PHY processor, the second upstream port being associated with a second upstream channel, wherein upstream signals from the second plurality of nodes are received via the second upstream port, wherein at least a portion of the second plurality of PHY layer components are coupled to at least a portion of the first plurality of PHY layer components via one or more physical components;

the access control system being operable to;

configure upstream communications from the first plurality of nodes to be processed by the first PHY processor;

configure upstream communications from the second plurality of nodes to be processed by the second PHY processor;

process upstream signals from a first portion of the first plurality of nodes at the first PHY processor;

process upstream signals from a second portion of the second plurality of nodes at the second PHY processor;

detect a first event or condition for triggering a dynamic re-configuration of at least one node-PHY processor association;

dynamically configure, in response to detecting the first event or condition, upstream communications from the first plurality of nodes to be processed by the second PHY processor; and

process, in response to the dynamic configuration, upstream signals from the first portion of the first plurality of nodes at the second PHY processor.

15. The system of claim 14:

wherein the first plurality of physical layer components includes a third upstream port, the third upstream port being associated with a third upstream channel;

the access control system being operable to;

process upstream signals from a third portion of the first plurality of nodes at the first PHY processor concurrently while upstream signals from the first portion of the first plurality of nodes are processed by the second PHY processor.

16. The system of claim 14 wherein the access control system operates in a cable network, wherein the access control system includes at least one cable modem termination system (CMTS), and wherein the first and second plurality of nodes are cable modems.

17. The system of claim 14:

wherein the first plurality of physical layer components includes a first splitter operable to communicatively couple the first upstream port to the first PHY processor and the second PHY processor; and

wherein the second plurality of physical layer components includes a second splitter operable to communicatively couple the first upstream port to the first PHY processor and the second PHY processor.

18. The system of claim 14 wherein the first event or condition relates to an upstream channel load balancing operation implemented at the access control system.

19. The system of claim 14, wherein the first plurality of physical layer components includes a third upstream port, the third upstream port being associated with a third upstream channel;

the access control system being operable to;

detect a bandwidth related issue at the first upstream channel;

identify, in response to detecting the bandwidth related issue, at least one alternate upstream channel to be used for performing load balancing on the first upstream channel and the at least one alternate upstream channel;

initiate, in response to detecting the bandwidth related issue, at least one load balancing operation for balancing bandwidth loads across selected upstream channels including the first and second upstream channels;

configure at least a portion of the first plurality of physical layer components to cause upstream signals received from a third portion of the first plurality of nodes via the third upstream port to be processed by the first PHY processor; and

process upstream signals from the third portion of the first plurality of nodes at the first PHY processor concurrently while upstream signals from the first portion of the first plurality of nodes are processed by the second PHY processor.

20. The system of claim 14, wherein the first event or condition relates to an issue or problem associated with the first upstream channel, the access control system being further operable to:

identify a first selected portion of nodes registered to utilize the first upstream channel for communications with the access control system;

identify, in response to detecting the first event or condition, a first alternate upstream channel to be used by the first selected portion of nodes for upstream communications with the access control system, wherein the access control system is operable to receive, at a third upstream port, upstream communications transmitted on the first alternate upstream channel;

dynamically cause, in response to detecting the first event or condition, upstream transmissions on the first upstream channel to be temporarily suspended during a first time interval;

dynamically cause, in response to detecting the first event or condition, upstream transmissions on the at least one alternate upstream channel to be temporarily suspended during the first time interval;

dynamically configure, in response to detecting the first event or condition, the third upstream port to communicate with a selected PHY processor;

dynamically cause the first selected portion of nodes to utilize the first alternate upstream channel for communicating with the access control system; and

dynamically cause, upstream transmissions on the first upstream channel and first alternate upstream channel to be resumed.

21. The system of claim 14, wherein the one or more physical components include one or more switches.

22. A method for facilitating communications in a cable network, the cable network including at least one cable modem termination system (CMTS) operable to communicate with a first plurality of cable modems of a first subscriber group via a first shared access upstream channel, and operable to communicate with second plurality of cable modems of a second subscriber group via a second shared access upstream channel, the at least one CMTS having a CMTS line card including a first plurality of physical (PHY) layer components, the first plurality of physical layer components including a first upstream port and a first PHY processor, wherein the first plurality of cable modems are physically coupled to the first upstream port, the first upstream port being associated with a first upstream channel, the CMTS line card of the at least one CMTS further including a second plurality of physical layer components, the second plurality of physical layer components including a second upstream port and a second PHY processor, wherein the second plurality of cable modems are physically coupled to the second upstream port, the second upstream port being associated with a second upstream channel, the method comprising:

configuring at least a portion of the first plurality of physical layer components to cause upstream signals received from the first plurality of nodes via the first upstream port to be processed by the first PHY processor;

configuring at least a portion of the second plurality of physical layer components to cause upstream signals received from the second plurality of nodes via the second upstream port to be processed by the second PHY processor, wherein at least a portion of the second plurality of PHY layer components are coupled to at least a portion of the first plurality of PHY layer components via one or more physical components;

processing upstream signals from a first portion of the first plurality of cable modems at the first PHY processor;

processing upstream signals from a second portion of the second plurality of cable modems at the second PHY processor;

detecting a first event or condition for triggering a dynamic re-configuration of at least one port-PHY processor configuration;

dynamically configuring, in response to detecting the first event or condition, at least a portion of the first plurality of physical layer components to cause upstream signals received from the first portion of the first plurality of nodes via the first upstream port to be processed by the second PHY processor, thereby enabling the upstream signals sent from the first portion of the plurality of nodes coupled to the first upstream port associated with the first upstream channel to be processed by the second PHY processor associated with the second upstream channel; and

processing, in response to the dynamic configuration, upstream signals from the first portion of the first plurality of cable modems at the second PHY processor.

23. The method of claim 22, wherein the first plurality of physical layer components includes a third upstream port, the third upstream port being associated with a third upstream channel, the method further comprising:

configuring the third upstream port to communicate with the first PHY processor; and

processing upstream signals from a third portion of the first plurality of cable modems at the first PHY processor concurrently while upstream signals from the first portion of the first plurality of cable modems are processed by the second PHY processor.

24. The method of claim 22, wherein the first plurality of physical layer components includes a third upstream port, the third upstream port being associated with a third upstream channel, the method further comprising:

detecting a bandwidth related issue at the first upstream channel;

identifying, in response to detecting the bandwidth related issue, at least one alternate upstream channel to be used for performing load balancing on the first upstream channel and the at least one alternate upstream channel;

initiating, in response to detecting the bandwidth related issue, at least one load balancing operation for balancing bandwidth loads across selected upstream channels including the first and second upstream channels;

configuring the third upstream port to communicate with the first PHY processor; and

processing upstream signals from a third portion of the first plurality of cable modems at the first PHY processor concurrently while upstream signals from the first portion of the first plurality of cable modems are processed by the second PHY processor.

25. The method of claim 22, wherein the first event or condition relates to an issue or problem associated with the first upstream channel, the access control method further comprising:

identifying a first selected portion of cable modems registered to utilize the first upstream channel for communications with the access control method;

identifying, in response to detecting the first event or condition, a first alternate upstream channel to be used by the first selected portion of cable modems for upstream communications with the access control method, wherein the access control method is operable to receive, at a third upstream port, upstream communications transmitted on the first alternate upstream channel;

dynamically causing, in response to detecting the first event or condition, upstream transmissions on the first upstream channel to be temporarily suspended during a first time interval;

dynamically causing, in response to detecting the first event or condition, upstream transmissions on the at least one alternate upstream channel to be temporarily suspended during the first time interval;

dynamically configuring, in response to detecting the first event or condition, the third upstream port to communicate with a selected PHY processor;

dynamically causing the first selected portion of cable modems to utilize the first alternate upstream channel for communicating with the access control method; and

dynamically causing, upstream transmissions on the first upstream channel and first alternate upstream channel to be resumed.

26. The method of claim 22 further comprising:

identifying duplicate upstream channel signals received at the first upstream port and second upstream port;

identifying a first portion of the duplicate upstream channel signals to processed by the access control method; and

identifying a second portion of the duplicate upstream channel signals which are to be ignored.

27. The method of claim 22, wherein the one or more physical components include one or more switches.

28. The method as recited in claim 22, wherein each upstream channel of the at least one CMTS is associated with a respective upstream port and a respective set of PHY layer components.

29. A system for facilitating communications in a cable network, the system comprising:

at least one cable modem termination system (CMTS) operable to communicate with a first plurality of cable modems of a first subscriber group via a first shared access upstream channel, and operable to communicate with second plurality of cable modems of a second subscriber group via a second shared access upstream channel;

the at least one CMTS comprising at least one CMTS line card including a first plurality of physical (PHY) layer components, the first plurality of physical layer components including a first upstream port and a first PHY processor, the first upstream port being associated with a first upstream channel, wherein the first plurality of cable modems are physically coupled to the first upstream port;

the CMTS line card of the at least one CMTS further including a second plurality of physical layer components, the second plurality of physical layer components including a second upstream port and a second PHY processor, the second upstream port being associated with a second upstream channel, wherein the second plurality of cable modems are physically coupled to the second upstream port;

the first plurality of physical layer components further including a third upstream port, the third upstream port being associated with a third upstream channel;

means for configuring at least a portion of the first plurality of physical layer components to cause upstream signals from the first plurality of nodes coupled to the first upstream port to be processed by the first PHY processor;

means for configuring at least a portion of the second plurality of physical layer components to cause upstream signals from the second plurality of nodes coupled to the second upstream port to be processed by the second PHY processor, wherein at least a portion of the second plurality of PHY layer components are coupled to at least a portion of the first plurality of PHY layer components via one or more physical components;

means for processing upstream signals from a first portion of the first plurality of cable modems at the first PHY processor;

means for processing upstream signals from a second portion of the second plurality of cable modems at the second PHY processor;

means for detecting a first event or condition for triggering a dynamic re-configuration of at least one port-PHY processor configuration;

means for dynamically configuring, in response to detecting the first event or condition, at least a portion of the first plurality of physical layer components to cause upstream signals from the first portion of the first plurality of nodes to be processed by the second PHY processor, thereby enabling the upstream signals sent from the first portion of the plurality of nodes coupled to the first upstream port associated with the first upstream channel to be processed by the second PHY processor associated with the second upstream channel;

means for processing, in response to the dynamic configuration, upstream signals from the first portion of the first plurality of cable modems at the second PHY processor;

means for configuring at least a portion of the first plurality of physical layer components to cause upstream signals from a third portion of the first plurality of cable modems coupled to the third upstream port to be processed by the first PHY processor; and

means for processing upstream signals from the third portion of the first plurality of cable modems at the first PHY processor concurrently while upstream signals from the first portion of the first plurality of cable modems are processed by the second PHY processor.

30. The system of claim 29, wherein the one or more physical components include one or more switches.

31. The system as recited in claim 29, wherein each upstream channel of the at least one CMTS is associated with a respective upstream port and a respective set of PHY layer components.