Apparatus and method of compensating for clock frequency and phase variations by processing packet delay values

Patent metadata

Field	Value
Publication number	US-9319164-B2
Application number	US-201313944788-A
Country	US
Kind code	B2
Filing date	Jul 17, 2013
Priority date	Apr 29, 2009
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

An apparatus and method are described for compensating for frequency and phase variations of electronic components by processing packet delay values. In one embodiment, a packet delay determination module determines packet delay values based on time values associated with a first and a second electronic component. A packet delay selection module selects a subset of the packet delay values based on the maximum frequency drift of the first electronic component. A statistical parameter determination module evaluates a first and a second parameter based on portions of the subset of packet delay values. A validation module validates the parameters when each portion the subset of packet delay values includes a minimum of at least two packet delay values. An adjustment module compensates for at least one of a frequency variation and a phase variation of the first electronic component based on the parameters if the parameters are both validated.

First claim

What is claimed is:

1. An apparatus, comprising:
a statistical parameter determination module configured to determine:
a value of a first parameter of a first statistical parameter type based on a first plurality of packet delay values;
a value of a second parameter of the first statistical parameter type based on a second plurality of packet delay values determined subsequent to the first plurality of packet delay values;
a value of a first parameter of a second statistical parameter type based on the first plurality of packet delay values, the second statistical parameter type being different from the first statistical parameter type; and
a value of a second parameter of the second statistical parameter type based on the second plurality of packet delay values; and

the statistical parameter determination module configured to send a signal to a network rearrangement detection module such that the network rearrangement detection module detects a network rearrangement based on the value of the first parameter of the first statistical parameter type, the value of the second parameter of the first statistical parameter type, the value of the first parameter of the second statistical parameter type, and the value of the second parameter of the second statistical parameter type;
the statistical parameter determination module being implemented in at least one of a memory or a processing device.

2. The apparatus of claim 1 , wherein the statistical parameter determination module is configured to select the first statistical parameter type based on the first plurality of packet delay values.

3. The apparatus of claim 1 , wherein the statistical parameter determination module is configured to select the first statistical parameter type based on the value of the first parameter of the second statistical parameter type.

4. The apparatus of claim 1 , wherein:
the first statistical parameter type is one of a minimum or a mean; and
the second statistical parameter type is one of a standard deviation or a variance.

5. The apparatus of claim 1 , wherein the statistical parameter determination module is configured to send the signal to the network rearrangement detection module such that the network rearrangement detection module detects the network rearrangement based on:
the value of the second parameter of the first statistical parameter type being different from the value of the first parameter of the first statistical parameter type by at least a first threshold; and
the value of the first parameter of the second statistical parameter type and the value of the second parameter of the second statistical parameter type each being less than a second threshold.

6. The apparatus of claim 1 , further comprising an adjustment module configured to compensate for a phase variation of an electronic component corresponding to a difference between the value of the second parameter of the first statistical parameter type and the value of the first parameter of the first statistical parameter type if the network rearrangement is detected.

7. The apparatus of claim 1 , further comprising a packet delay selection module configured to select a subset of a plurality of packet delay values as the first plurality of packet delay values based on a maximum frequency drift of an electronic component, and to determine the first plurality of packet delay values based on the subset of the plurality of packet delay values and not on the remaining values in the plurality of packet delay values.

8. The apparatus of claim 1 , wherein:
the statistical parameter determination module is configured to determine a value of a parameter of a third statistical parameter type based on a third plurality of packet delay values determined subsequent to the second plurality of packet delay values; and
the third statistical parameter type is one of a minimum, a mean, a median, a mode, or a maximum.

9. The apparatus of claim 1 , wherein:
the statistical parameter determination module is configured to determine a parameter of a third statistical parameter type based on a third plurality of packet delay values determined subsequent to the second plurality of packet delay values; and
the third statistical parameter type is one of a standard deviation, a variance, or a higher-order moment.

10. An apparatus, comprising:
a statistical parameter determination module configured to determine:
a value of a first parameter of a statistical parameter type based on a first plurality of packet delay values; and
a value of a second parameter of the statistical parameter type based on a second plurality of packet delay values determined subsequent to the first plurality of packet delay values;

the statistical parameter determination module configured to send a signal to a network rearrangement detection module such that the network rearrangement detection module detects a network rearrangement based on the value of the second parameter of the statistical parameter type being different from the value of the first parameter of the statistical parameter type by at least a first threshold;
the statistical parameter determination module being implemented in at least one of a memory or a processing device.

11. The apparatus of claim 10 , wherein:
the statistical parameter determination module is configured to select the statistical parameter type based on the first plurality of packet delay values; and
the statistical parameter type is one of a minimum or a mean.

12. The apparatus of claim 10 , wherein:
the statistical parameter type is a first statistical parameter type; and
the statistical parameter determination module configured to determine:
a value of a first parameter of a second statistical parameter type based on the first plurality of packet delay values, the second statistical parameter type being different from the first statistical parameter type; and
a value of a second parameter of the second statistical parameter type based on the second plurality of packet delay values;

the statistical parameter determination module configured to select the first statistical parameter type based on the value of the first parameter of the second statistical parameter type.

13. The apparatus of claim 12 , wherein:
the statistical parameter determination module is configured to send the signal to the network rearrangement detection module such that the network rearrangement detection module detects the network rearrangement based on the value of the first parameter of the second statistical parameter type and the value of the second parameter of the second statistical parameter type each being less than a second threshold; and
the second statistical parameter type is one of a standard deviation or a variance.

14. The apparatus of claim 10 , further comprising an adjustment module configured to compensate for a phase variation of an electronic component corresponding to a difference between the value of the second parameter of the statistical parameter type and the value of the first parameter of the statistical parameter type if the network rearrangement is detected.

15. An apparatus, comprising:
a first module configured to detect a network rearrangement based on:
a value of a first parameter of a first statistical parameter type that was determined based on a first plurality of packet delay values;
a value of a second parameter of the first statistical parameter type that was determined based on a second plurality of packet delay values determined subsequent to the first plurality of packet delay values;
a value of a first parameter of a second statist

Assignees

• Juniper Networks Inc

Inventors

• Barry Charles F
• Subramanian Meenakshi S
• Pan Feng Frank
• Shen Tian Alan
• Kruzinski Philip
• Zhao Guochun George
• Natesan Deviprasad
• Jorgensen David R

Classifications

• H04J3/0682 Primary

  by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging · CPC title

• H04J3/0667 Primary

  Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays (arrangements for monitoring round trip delays in packet switching networks H04L43/0864) · CPC title