Traffic flow scheduling techniques implemented on bonded channels of a shared access cable network

• US 8,059,546 B2
• Filed: 03/13/2009
• Issued: 11/15/2011
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bernstein, Alon, Charny, Anna, Pai, Prashant
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Patel; Chandrahas
• Application Number:
  US12/404,224
• Publication Number:
  US 20100061235A1
• Time in Patent Office: 977 Days
• Field of Search: 370/236, 370/350, 455/434, 455/553.1
• US Class Current: 370/236
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/41 by acting on aggregated flows or links
• CPC Class Codes: H04L 47/60 implementing hierarchical scheduling
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Various techniques are disclosed for managing traffic flow for transport over a plurality of communication channels of a shared access cable network. According to various embodiments, one or more devices of the cable network (such as, for example, a Cable Modem Termination System (CMTS)), may be operable to implement at least a portion of the traffic flow management techniques. In at least one embodiment, one or more aspects of the traffic flow management techniques disclosed herein may be used for performing real-time shaping of traffic flows across multiple different channels of a DOCSIS channel bonding group. In some embodiments, various different traffic shaping and/or traffic scheduling techniques may be employed (e.g., in DOCSIS 3.0 compatible cable networks) to reduce and/or mitigate issues which, for example, may arise as a result of an inability to represent traffic schedulers as tree-based hierarchies. Other aspects are disclosed for implementing quality of service (QoS) procedures on shared access network(s), such as for example hybrid fiber/coaxial (HFC) cable networks.

Claims

1. A system for managing traffic flow for transport over a plurality of communication channels on a shared access cable network, the system comprising:

at least one processor;

at least one interface operable to provide a communication link to at least one network device; and

memory;

the system being operable to shape a plurality of different traffic flows to be transported over the plurality of different communication channels of the shared access cable network;

wherein the plurality of communication channels includes a first communication channel, a second communication channel, and a third communication channel;

wherein the first communication channel and the second communication channel are associated with a first channel group;

wherein the second communication channel and the third communication channel are associated with a second channel group;

wherein the first channel group has associated therewith a first plurality of queues including a first queue and a second queue;

wherein the second channel group has associated therewith a second plurality of queues including a third queue and a fourth queue;

wherein each of the first, second, third, and fourth queues is capable of containing a respective number of packets stored for transmission via the channels in the associated channel group; and

wherein the shaping of the plurality of different traffic flows includes;

determining whether a first number of packets stored in the first queue has exceeded a first threshold number of packets, wherein the first queue is associated with the first channel group and associated with the first communication channel;

determining whether a second number of packets stored in the second queue has exceeded a second threshold number of packets, wherein the second queue is associated with the first channel group and associated with the second communication channel;

initiating at least one operation for suspending or disabling, during a first time interval, traffic flow associated with the first channel group in response to detecting that at least one of the queues associated with the first channel group has exceeded its associated threshold number of packets;

determining whether a third number of packets stored in the third queue has exceeded third threshold number of packets, wherein the third queue is associated with the second channel group and associated with the second communication channel;

determining whether a fourth number of packets stored in the fourth queue has exceeded fourth threshold number of packets, wherein the fourth queue is associated with the second channel group and associated with the third communication channel; and

initiating at least one operation for suspending or disabling, during a second time interval, traffic flow associated with the second channel group in response to detecting that at least one of the queues associated with the second channel group has exceeded its associated threshold number of packets.

2. The system of claim 1, wherein the shaping of the plurality of different traffic flows includes:

determining whether traffic flow associated with the first channel group is suspended or disabled;

initiating at least one operation for enabling or resuming traffic flow associated with the first channel group in response to a determination that respective threshold number of packets associated with each of the first plurality of queues is satisfied;

determining whether traffic flow associated with the second channel group is suspended or disabled; and

initiating at least one operation for enabling or resuming traffic flow associated with the second channel group in response to a determination that respective threshold number of packets associated with each of the second plurality of queues is satisfied.

3. The system of claim 1:

wherein the shared access cable network is configured as a Hybrid Fiber Coax (HFC) cable network that is compatible with a Data-Over-Cable Service Interface Specification (DOCSIS) communication protocol;

wherein the system is implemented as a Cable Modem Termination System (CMTS) of the shared access cable network; and

wherein the first channel group corresponds to a DOCSIS channel bonding group in accordance with the DOCSIS communication protocol.

4. A system for managing traffic flow for transport over a plurality of communication channels on a shared access cable network, the system comprising:

at least one processor;

at least one interface operable to provide a communication link to at least one network device; and

memory;

the system being operable to;

receive a first packet, the first packet having associated therewith a first set of characteristics, the first set of characteristics comprising a first service flow identifier representing a first service flow associated with the first packet, the first service flow comprising a Media Access Control layer data stream for transport of packets between a cable network service provider and a first cable modem;

identify, using at least a portion of the first set of characteristics, a first channel group associated with the first service flow, the first channel group comprising a plurality of communication channels which have been allocated for use in transporting data traffic associated with the first service flow, wherein at least one of the plurality of communication channels is also included within a second channel group, wherein the first channel group has associated therewith a first plurality of queues, wherein each of the plurality of communication channels has associated therewith at least one respective queue of the first plurality of queues, wherein each of the first plurality of queues has associated therewith a respective available queue capacity value representing an amount of total memory which is available for use by a given queue of the first plurality of queues, wherein each of the first plurality of queues comprises a respective number of packets stored for transmission via the respective communication channel;

determine whether a respective number of packets stored in each of the queues associated with the first channel group and associated with the first communication channel has exceeded, during a first time interval, a threshold number of packets associated with its respective queue; and

initiate at least one operation for suspending or disabling, during a second time interval, traffic flow associated with the first channel group in response to detecting that each of the queues associated with the first channel group has exceeded its associated threshold number of packets.

5. The system of claim 4:

wherein the at least one operation for suspending or disabling of traffic flow associated with the first channel group includes prohibiting at least one packet from being enqueued in any of the first plurality of queues during the second time interval.

6. The system of claim 4 being further operable to:

identify, using a first set of criteria, a first queue from the first plurality of queues, wherein the first set of criteria includes criteria for identifying and selecting, from the first plurality of queues, a specific queue having associated therewith a relatively largest available queue capacity value as of a given time T; and

initiate at least one operation for enqueing the received packet in the first queue.

7. The system of claim 4:

wherein the shared access cable network is configured as a Hybrid Fiber Coax (HFC) cable network that is compatible with a Data-Over-Cable Service Interface Specification (DOCSIS) communication protocol;

wherein the system is implemented as a Cable Modem Termination System (CMTS) of the shared access cable network; and

wherein the first channel group corresponds to a DOCSIS channel bonding group in accordance with the DOCSIS communication protocol.

8. A system for managing traffic flow for transport over a plurality of communication channels on a shared access cable network, the system comprising:

at least one processor;

at least one interface operable to provide a communication link to at least one network device; and

memory;

the system being operable to;

detect a first packet dequeue event relating to a dequeuing of a first packet from a first queue associated with a first channel group, the first channel group comprising a plurality of communication channels allocated for use in transporting data traffic associated with a first service flow, the first service flow comprising a Media Access Control layer data stream for transport of packets between a cable network service provider and a first cable modem, wherein the first channel group has associated therewith a first plurality of queues including the first queue, wherein each of the plurality of communication channels has associated therewith at least one respective queue of the first plurality of queues, wherein each of the first plurality of queues comprises a respective number of packets stored for transmission via the respective communication channel, wherein at least one of the plurality of communication channels is also included within a second channel group;

identify, using information associated with the first queue, the first channel group which is associated with the first queue;

determine whether traffic flow control is asserted for the first channel group, wherein the assertion of traffic flow control for the first channel group is characterized by a suspension of traffic flow on the first plurality of communication channels of the first channel group; and

perform at least one operation for deasserting traffic flow control at the first channel group in response to a determination that traffic flow control is asserted for the first channel group and in response to detecting the dequeuing of the first packet from the first queue, wherein the deassertion of traffic flow control for the first channel group is characterized by a resumption of traffic flow on the first plurality of communication channels of the first channel group.

9. The system of claim 8:

wherein the at least one operation for deasserting traffic flow control at the first channel group includes enabling at least one packet to be enqueued in at least one of the first plurality of queues.

10. The system of claim 8:

wherein the shared access cable network is configured as a Hybrid Fiber Coax (HFC) cable network that is compatible with a Data-Over-Cable Service Interface Specification (DOCSIS) communication protocol;

wherein the system is implemented as a Cable Modem Termination System (CMTS) of the shared access cable network; and

wherein the first channel group corresponds to a DOCSIS channel bonding group in accordance with the DOCSIS communication protocol.

11. A method for managing traffic flow for transport over a plurality of communication channels on a shared access cable network, the method comprising:

receiving a first packet, the first packet having associated therewith a first set of characteristics, the first set of characteristics comprising a first service flow identifier representing a first service flow associated with the first packet, the first service flow comprising a Media Access Control layer data stream for transport of packets between a cable network service provider and a first cable modem;

identifying, using at least a portion of the first set of characteristics, a first channel group associated with the first service flow, the first channel group comprising a plurality of communication channels which have been allocated for use in transporting data traffic associated with the first service flow, wherein the first channel group has associated therewith a first plurality of queues, wherein each of the plurality of communication channels has associated therewith at least one respective queue of the first plurality of queues, wherein each of the first plurality of queues comprises a respective number of packets stored for transmission via the respective communication channel, wherein each of the first plurality of queues has associated therewith a respective available queue capacity value representing an amount of total memory which is available for use by a given queue of the first plurality of queues, wherein at least one of the plurality of communication channels is also included within a second channel group;

determining whether each of the queues associated with the first channel group and associated with the first communication channel has exceeded, during a first time interval, a threshold number of packets associated with its respective queue; and

initiating at least one operation for suspending or disabling, during a second time interval, traffic flow associated with the first channel group in response to detecting that each of the queues associated with the first channel group has exceeded its associated threshold number of packets.

12. The method of claim 11:

wherein the at least one operation for suspending or disabling of traffic flow associated with the first channel group includes prohibiting at least one packet from being enqueued in any of the first plurality of queues during the second time interval.

13. The method of claim 11 further comprising:

identifying, using a first set of criteria, a first queue from the first plurality of queues, wherein the first set of criteria includes criteria for identifying and selecting, from the first plurality of queues, a specific queue having associated therewith a relatively largest available queue capacity value as of a given time T; and

initiating at least one operation for enqueing the received packet in the first queue.

14. The method of claim 11:

wherein the shared access cable network is configured as a Hybrid Fiber Coax (HFC) cable network that is compatible with a Data-Over-Cable Service Interface Specification (DOCSIS) communication protocol;

wherein the method is implemented at a Cable Modem Termination System (CMTS) of the shared access cable network; and

wherein the first channel group corresponds to a DOCSIS channel bonding group in accordance with the DOCSIS communication protocol.

15. A method for managing traffic flow for transport over a plurality of communication channels on a shared access cable network, the method comprising:

detecting a first packet dequeue event relating to a dequeuing of a first packet from a first queue associated with a first channel group, the first channel group comprising a plurality of communication channels allocated for use in transporting data traffic associated with a first service flow, the first service flow comprising a Media Access Control layer data stream for transport of packets between a cable network service provider and a first cable modem, wherein the first channel group has associated therewith a first plurality of queues including the first queue, wherein each of the plurality of communication channels has associated therewith at least one respective queue of the first plurality of queues, wherein each of the first plurality of queues comprises a respective number of packets stored for transmission via the respective communication channel, wherein at least one of the plurality of communication channels is also included within a second channel group;

identifying, using information associated with the first queue, the first channel group which is associated with the first queue;

determining whether traffic flow control is asserted for the first channel group, wherein the assertion of traffic flow control for the first channel group is characterized by a suspension of traffic flow on the first plurality of communication channels of the first channel group; and

performing at least one operation for deasserting traffic flow control at the first channel group in response to a determination that traffic flow control is asserted for the first channel group and in response to detecting the dequeuing of the first packet from the first queue, wherein the deassertion of traffic flow control for the first channel group is characterized by a resumption of traffic flow on the first plurality of communication channels of the first channel group.

16. The method of claim 15:

wherein the at least one operation for deasserting traffic flow control at the first channel group includes enabling at least one packet to be enqueued in at least one of the first plurality of queues.

17. The method of claim 15:

wherein the shared access cable network is configured as a Hybrid Fiber Coax (HFC) cable network that is compatible with a Data-Over-Cable Service Interface Specification (DOCSIS) communication protocol;

wherein the method is implemented at a Cable Modem Termination System (CMTS) of the shared access cable network; and

wherein the first channel group corresponds to a DOCSIS channel bonding group in accordance with the DOCSIS communication protocol.