Dynamically adjusting liveliness detection intervals for periodic network communications

• US 9,258,234 B1
• Filed: 12/28/2012
• Issued: 02/09/2016
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Addepalli, Meher Aditya Kumar, Singh, Prashant
• Primary Examiner(s): Mesfin, Yemane
• Assistant Examiner(s): Elmejjarmi, Abdelillah
• Application Number:
  US13/730,737
• Time in Patent Office: 1,138 Days
• Field of Search: 370/229, 370/237
• US Class Current: 1/1
• CPC Class Codes: H04L 43/06 Generation of reports
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/103 with adaptive polling, i.e. dynamically adapting the polling rate
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/826 Involving periods of time
• CPC Class Codes: H04L 67/142 Managing session states for stateless protocols; Signalling session states; State transitions; Keeping-state mechanisms

Abstract

In general, techniques are described to dynamically adjust a session detection time defined by a timer in accordance with a bidirectional forwarding detection (BFD) protocol. The techniques utilize existing hardware and BFD software infrastructure. An example network device includes a memory, programmable processor(s), and a control unit configured to execute a timer, receive one or more packets provided by the BFD protocol, detect, based on the received one or more packets, a congestion condition associated with a link via which the network device is coupled to a network, adjust, based on the detected congestion condition, a session detection time defined by the timer, and in response to a failure to receive a packet provided by the BFD protocol within the session detection time defined by the timer, detect a failure associated with the link.

Claims

1. A method comprising:

receiving, by a network device, bidirectional forwarding detection (BFD) packets for a BFD session for monitoring connectivity with a peer network device;

determining, by the network device, a weighted moving average in which more recent timing measurements of a series of timing measurements are weighted with greater weights, respectively, relative to earlier timing measurements of the series of timing measurement, the series of timing measurements based on respective receipt times of the BFD packets;

adjusting, by the network device and based on the weighted moving average, a detection multiplier that specifies a multiple of a negotiated transmission time interval for the BFD session to define, at least in part, a session detection time for the BFD session; and

detecting, by the network device and based at least on a failure to receive a subsequent BFD packet for the BFD session within the session detection time for the BFD session, a failure of connectivity with the peer network device.

2. The method of claim 1,

wherein the BFD session is associated with a configured detection multiplier and the detection multiplier, and

wherein adjusting the detection multiplier comprises determining the detection multiplier for the BFD session as a product of the configured detection multiplier and the weighted moving average.

3. The method of claim 1, wherein the detection multiplier is a non-integer value.

4. The method of claim 1,

wherein the BFD session is associated with a configured detection multiplier and the detection multiplier, and

wherein adjusting the detection multiplier comprises:

determining a computed detection multiplier as a product of the configured detection multiplier and the weighted moving average;

setting the detection multiplier for the BFD session to an upper bound if the computed detection multiplier is greater than the upper bound; and

setting the detection multiplier for the BFD session to a lower bound if the computed detection multiplier is less than a lower bound.

5. The method of claim 1,

wherein the series of timing measurements comprises a series of delays associated with respective receipt times for consecutive BFD packets of the BFD packets, and

wherein determining the weighted moving average of the series of timing measurements comprises determining a weighted moving average of the series of delays.

6. The method of claim 1, further comprising:

applying the detection multiplier to a receipt interval to calculate the session detection time; and

setting a timer to expire at the session detection time.

7. The method of claim 1,

wherein the series of timing measurements comprises series of jitters associated with respective receipt times for consecutive BFD packets of the BFD packets, and

wherein determining the weighted moving average of the series of timing measurements comprises determining a weighted moving average of the series of jitters.

8. A network device comprising:

a memory;

and

a control unit having one or more programmable processors and configured to;

execute a timer;

receive bidirectional forwarding detection (BFD) packets for a BFD session for monitoring connectivity with a peer network device;

determine a weighted moving average in which more recent timing measurements of a series of timing measurements are weighted with greater weights, respectively, relative to earlier timing measurements of the series of timing measurement, the series of timing measurements based on respective receipt times of the BFD packets;

adjust, based on the weighted moving average, a detection multiplier that specifies a multiple of a negotiated transmission time interval for the BFD session to define, at least in part, a session detection time for the BFD session; and

detect, based at least on a failure to receive a subsequent BFD packet for the BFD session within the session detection time for the BFD session, a failure of connectivity with the peer network device.

9. The network device of claim 8,

wherein the BFD session is associated with a configured detection multiplier and the detection multiplier, and

wherein to adjust the detection multiplier the control unit is further configured to determine the detection multiplier for the BFD session as a product of the configured detection multiplier and the weighted moving average.

10. The network device of claim 8, wherein the detection multiplier is a non-integer value.

11. The network device of claim 8,

wherein the BFD session is associated with a configured detection multiplier and the detection multiplier, and

wherein to adjust the session multiplier the control unit is further configured to:

determine a computed detection multiplier as a product of the configured detection multiplier and the weighted moving average;

set the detection multiplier for the BFD session to an upper bound if the computed detection multiplier is greater than the upper bound; and

set the detection multiplier for the BFD session to a lower bound if the computed detection multiplier is less than a lower bound.

12. The network device of claim 8,

wherein the series of timing measurements comprises a series of delays associated with respective receipt times for consecutive BFD packets of the BFD packets, and

wherein, to determine the weighted moving average of the series of timing measurements, the control unit is further configured to determine a weighted moving average of the series of delays.

13. The network device of claim 8, wherein the control unit is configured to:

apply the detection multiplier to a receipt interval to calculate the session detection time; and

set a timer to expire at the session detection time.

14. The network device of claim 8, wherein

the series of timing measurements comprises a series of jitters associated with respective receipt times for consecutive BFD packets of the BFD packets, and

wherein, to determine the weighted moving average of the series of timing measurements, the control unit is further configured to determine a weighted moving average of the series of jitters.

15. A non-transitory computer-readable storage medium encoded with instructions that, when executed, cause one or more programmable processors of a network device to:

receive bidirectional forwarding detection (BFD) packets for a BFD session for monitoring connectivity with a peer network device;

determine a weighted moving average in which more recent timing measurements of a series of timing measurements are weighted with greater weights, respectively, relative to earlier timing measurements of the series of timing measurement, the series of timing measurements based on respective receipt times of the BFD packets;

adjust, based on the weighted moving average, a detection multiplier that specifies a multiple of a negotiated transmission time interval for the BFD session to define, at least in part, a session detection time for the BFD session; and

detect, based at least on a failure to receive a subsequent BFD packet for the BFD session within the session detection time for the BFD session, a failure of connectivity with the peer network device.