Method and apparatus for providing timing analysis for packet streams over packet carriers

1. A method for generating timing offsets associated with a network circuit, comprising:

receiving a first data packet traveling across a first circuit emulation service (“CES”) circuit;

obtaining a first arrival timestamp associated with the first data packet;

storing the first arrival timestamp in a first timestamp buffer based on a first-in first-out (“FIFO”) storage sequence;

identifying an oldest arrival timestamp in the first timestamp buffer in accordance with the FIFO storage sequence;

generating a first offset by comparing between the first arrival timestamp and the oldest arrival timestamp;

generating a timing report in response to the first offset; and

recording rate lock status in a log when the first offset falls within a predefined range.

2. The method of claim 1 , further comprising sending a warning message when the first offset falls outside of a predefined range.

3. The method of claim 1 , wherein receiving a first data packet traveling across the first CES circuit includes receiving a bit stream transported by a T1 carrier.

4. The method of claim 1 , wherein receiving a first data packet traveling across the first CES circuit includes receiving a bit stream transported by an E1 carrier.

5. The method of claim 1 , wherein obtaining the first arrival timestamp associated with the first data packet includes generating a timestamp at a time when the first data packet is received at a port of a network device.

6. The method of claim 1 , wherein storing the first arrival timestamp in the first timestamp buffer includes storing the first arrival timestamp in a circular buffer containing a predefined number of entries for storing timestamps.

7. The method of claim 6 , wherein storing the first arrival timestamp in the circular buffer containing a predefined number of entries for storing timestamps includes identifying one storage entry in the circular buffer for storing the first arrival timestamp.

8. The method of claim 1 , wherein identifying an oldest arrival timestamp in the first timestamp buffer in accordance with the FIFO storage sequence includes retrieving earliest stored content from the first timestamp buffer.

9. The method of claim 1 , wherein generating the first offset by comparing between the first arrival timestamp and the oldest timestamp includes generating parts per million (“PPM”) data representing the first offset in response to comparison between the first arrival timestamp and the oldest timestamp.

10. The method of claim 9 , wherein generating the timing report in response to the first offset includes setting an alert when the first offset is greater than a predefined PPM.

11. The method of claim 1 , further comprising:

receiving a second data packet traveling across the first CES circuit;

obtaining a second arrival timestamp associated with the second data packet; and

storing the second arrival timestamp in the first timestamp buffer based on a FIFO storage sequence.

12. The method of claim 11 , further comprising:

receiving a third data packet traveling across a second CES circuit;

obtaining a third arrival timestamp associated with the third data packet;

storing the third arrival timestamp in a second timestamp buffer based on a FIFO storage sequence;

identifying an oldest arrival timestamp in the second timestamp buffer in accordance with the FIFO storage sequence;

generating a third offset by comparing between the third arrival timestamp and the oldest arrival timestamp of the second timestamp buffer; and

generating a second timing report in response to the third offset.

13. A method for providing timing analysis of a network circuit, comprising:

generating, by a packet switching device, a plurality of arrival timestamps in accordance with a plurality of data packets traveling across a circuit emulation service (“CES”) circuit;

calculating a set of offsets representing in parts per million (“PPM”) data in response to comparison between the plurality of arrival timestamps and prior stored arrival timestamps in a first-in first-out buffer;

obtaining a predefined wander threshold associated with the CES circuit;

recording an anomaly in a log and raising an alarm when any of the set of offsets exceeds the predefined wander threshold;

identifying a change of ingress rate in response to the set of offsets;

comparing the change of ingress rate with the predefined wander threshold; and

logging lost rate lock when the change of ingress rate is greater than the predefined wander threshold.

14. The method of claim 13 , further comprising:

identifying a change of egress rate in response to the set of offsets;

comparing the change of egress rate with the predefined wander threshold; and

logging a second anomaly in the log when the change of egress rate is greater than the predefined wander threshold.

15. The method of claim 13 , further comprising:

generating a timing analysis status report based on the log; and

forwarding the timing analysis status report to user on-demand.

16. A network device, configured to generate timing offsets associated with a network circuit, comprising:

an ingress component coupled to a first circuit emulation service (“CES”) circuit and configured to generate a first timestamp indicating arrival time of a first data packet traveling across the first CES circuit;

a first timestamp buffer coupled to the ingress component and configured to store a plurality of arrival timestamps based on a first-in first-out (“FIFO”) storage sequence;

a rate calculator coupled to the first timestamp buffer and configured to compare an oldest timestamp in the first timestamp buffer with newly arrived timestamp to identify an offset;

an ingress rate manager coupled to the rate calculator and configured to generate a timing report in response to the offset; and

a log coupled to the ingress rate manager and configured to record rate lock status when the first offset falls within a predefined range.

17. The network device of claim 16 , wherein the ingress component is coupled to a second CES circuit and configured to generate a second timestamp indicating arrival time of a second data packet traveling across the second CES circuit.

18. The network device of claim 17 , further comprising a second timestamp buffer coupled to the ingress component and configured to store the second timestamp based on a circular storage sequence.