Methods and apparatus for defining a flow control signal related to a transmit queue

• US 8,593,970 B2
• Filed: 07/03/2012
• Issued: 11/26/2013
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Godbole, Avanindra, Frailong, Jean-Marc, Jadav, Abhijeet Sampatrao, Jain, Naveen, Sindhu, Pradeep, Basu, Arghajit
• Primary Examiner(s): Duong, Frank
• Application Number:
  US13/541,080
• Publication Number:
  US 20120269065A1
• Time in Patent Office: 511 Days
• Field of Search: 370229-235, 370386-388, 370412-413
• US Class Current: 370/239
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/267 sent by the destination endpoint network streaming of media packets with control of the source by the destination H04L65/613
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/52 by attributing bandwidth to queues
• CPC Class Codes: H04L 49/9078 using an external memory or storage device

Abstract

In one embodiment, a processor-readable medium can store code representing instructions that when executed by a processor cause the processor to receive a value representing a congestion level of a receive queue and a value representing a state of a transmit queue. At least a portion of the transmit queue can be defined by a plurality of packets addressed to the receive queue. A rate value for the transmit queue can be defined based on the value representing the congestion level of the receive queue and the value representing the state of the transmit queue. The processor-readable medium can store code representing instructions that when executed by the processor cause the processor to define a suspension time value for the transmit queue based on the value representing the congestion level of the receive queue and the value representing the state of the transmit queue.

Claims

1. A non-transitory processor-readable medium storing code representing instructions that when executed by a processor cause the processor to:

send, based on a state of a receive queue, a first flow control signal to a transmit side of a link including a transmit queue, the first flow control signal configured to trigger suspension of transmission, during a first suspension time period having a duration, of a first packet associated with the transmit queue to a memory defining the receive queue, the receive queue and the transmit queue collectively defining a portion of a first stage of queues logically nested outside of a second stage of queues; and

send, in response to an indicator that at least one of a state of the transmit queue or the state of the receive queue has changed, a second flow control signal to the transmit side of the link, the second flow control signal configured to trigger suspension of transmission, during a second suspension time period having a duration different from the duration of the first suspension time period, of a second packet associated with the transmit queue to the memory.

2. The non-transitory processor-readable medium of claim 1, wherein the first flow control signal includes a rate value based on the state of the receive queue.

3. The non-transitory processor-readable medium of claim 1 further storing code representing instructions that when executed by the processor cause the processor to:

define the first flow control signal based on the state of the receive queue and a state of a portion of a path between the receive queue and the transmit queue.

4. The non transitory processor-readable medium of claim 1, wherein the receive queue is a first receive queue,

the processor-readable medium further storing code representing instructions that when executed by the processor cause the processor to:

define a third suspension time period having a duration in response to a third packet, different from the first packet and the second packet, being received at a second receive queue from the transmit queue; and

associate a non-feedback indicator with the third suspension time period when the duration of the third suspension time period is less than the duration of the first suspension time period.

5. The non-transitory processor-readable medium of claim 1, wherein the state of the receive queue at a specified time is a congestion level of the receive queue at the specified time.

6. The non-transitory processor-readable medium of claim 1, wherein the state of the transmit queue at a specified time is a flow state of the transmit queue at the specified time.

7. The non-transitory processor-readable medium of claim 1, wherein the second packet is included in the transmit queue at a first time,

the processor-readable medium further storing code representing instructions that when executed by the processor cause the processor to:

receive a third packet on a receive side of the link at a second time before the first time; and

determine on the receive side of the link the state of the transmit queue based on at least one of the third packet or data associated with the third packet.

8. A non-transitory processor-readable medium storing code representing instructions that when executed by a processor cause the processor to:

send, to a flow control module, a flow control signal including a rate value for a transmit queue that is based on (1) a value representing a congestion level of a receive queue and (2) a value representing a state of the transmit queue, at least a portion of the transmit queue being defined by a plurality of packets addressed to the receive queue, the flow control signal includes a suspension time value for the transmit queue that is based on the value representing the congestion level of the receive queue and the value representing the state of the transmit queue.

9. The non-transitory processor-readable medium of claim 8, wherein the state of the transmit queue is a flow control state of the transmit queue, the transmit queue is associated with a transmit side of a link, the receive queue is associated with a receive side of the link,

the suspension time value for the transmit queue and the rate value for the transmit queue are sent from the receive side of the link to the transmit side of the link.

10. The non-transitory processor-readable medium of claim 8, wherein the flow control signal is configured to modify transmission of the plurality of packets from the transmit queue based on at least one of the rate value or the suspension time value.

11. The non-transitory processor-readable medium of claim 8, wherein the transmit queue is associated with a transmit side of a link, the receive queue is associated with a receive side of the link, at least one of the suspension time value or the rate value is defined based on a value representing a bandwidth available for transmission of a flow control signal from the receive side of the link to the transmit side of the link.

12. The non-transitory processor-readable medium of claim 8, wherein the rate value and the suspension time value are included in a single flow control frame.

13. The non-transitory processor-readable medium of claim 8, wherein the value representing the state of the transmit queue is calculated based on data associated with the plurality of packets.

14. The non-transitory processor-readable medium of claim 8, wherein the rate value of the transmit queue is a first rate value of the transmit queue, the suspension time value of the transmit queue is a first suspension time value of the transmit queue,

the processor-readable medium further storing code representing instructions that when executed by a processor cause the processor to:

receive an indicator that at least one of the congestion level of the receive queue or the state of the transmit queue has changed; and

define at least one of a second rate value of the transmit queue or a second suspension time value of the transmit queue in response to the indicator, the second rate value being different from the first rate value, the second suspension time value being different from the first suspension time value.

15. The non-transitory processor-readable medium of claim 8, further storing code representing instructions that when executed by the processor cause the processor to:

prevent sending at least one of the rate value or the suspension time value in response to a value representing a state of a feedback path associated with the transmit queue and the receive queue.

16. An apparatus, comprising:

a control module implemented in at least one of a processor or a memory, the control module configured to send a first flow control signal based on a data flow associated with a first flow control loop, the first flow control loop including a link, a first stage of queues, and a second stage of queues disposed within a transmission path between the link and the first stage of queues,

the control module configured to send a second flow control signal based on a data flow within a second flow control loop, the second flow control loop including the second stage of queues and the link, the second flow control loop excluding the first stage of queues, the second flow control signal including a rate value for a transmit queue associated with the second flow control loop and a suspension time value for the transmit queue associated with the second flow control loop.

17. The apparatus of claim 16, wherein the data flow associated with the second flow control loop is from the transmit queue, the control module is configured to define a value representing a state of the transmit queue based on the data flow associated with the second flow control loop, the control module is configured to define the rate value and the suspension time value based on the value representing the state of the transmit queue.

18. The apparatus of claim 16, wherein the second flow control loop is a priority-based flow control loop.

19. The apparatus of claim 16, wherein the control module is configured to define a third flow control signal based on a data flow associated with a third flow control loop including the link, the third flow control loop excluding the first stage of queues and the second stage of queues.

20. The apparatus of claim 16, wherein the first stage of queues is logically nested outside of the second stage of queues, the second stage of queues is logically nested outside of the link.