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

• US 10,164,890 B2
• Filed: 09/11/2017
• Issued: 12/25/2018
• Est. Priority Date: 04/11/2013
• Status: Active Grant

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Inventors: Sasak, Anthony Leonard, O'Brien, Christopher V.
• Primary Examiner(s): Qin, Zhiren
• Application Number:
  US15/700,810
• Publication Number:
  US 20170373981A1
• Time in Patent Office: 470 Days
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04J 3/065 using timestamps
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04L 41/064 involving time analysis
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/621 Individual queue per connection or flow, e.g. per VC
• CPC Class Codes: H04L 47/6245 Modifications to standard FIFO or LIFO

Abstract

A network device such as a router or switch, in one embodiment, includes a timing analyzer which is capable of providing timing analysis over one or more network circuits. The timing analyzer, in one aspect, receives a data packet traveling across a circuit emulation service (“CES”) circuit such as T1 or E1 circuit. Upon obtaining an arrival timestamp associated with the data packet, the arrival timestamp is stored in a timestamp buffer in accordance with a first-in first-out (“FIFO”) storage sequence. After identifying the oldest arrival timestamp in the timestamp buffer, an offset is generated based on the result of comparison between the arrival timestamp and the oldest timestamp. The timing analyzer can also be configured to generate timing reports on-demand based on generated offset(s).

Claims

1. A network layout, configured to transmit data packets from a source to a destination via a network transmission, comprising:

a packet switched network (“

PSN”

) containing one or more circuit emulation service (“

CES”

) circuits for transmitting data from a source to a destination;

a first node coupled to the PSN and configured to send a stream of packets to a first destination via the PSN; and

a second node coupled to the PSN and configured to receive the stream of packets from the first node, the second node configured to inform carrier potential failure associated with a CES circuit based on timing offsets calculated in accordance with an arrival timestamp of the stream of packets, wherein the second node includes at one network device, wherein the network device is configured to obtain an arrival timestamp associated with the stream of data packets, to store the arrival timestamp in a timestamp buffer based on a first-in first-out (“

FIFO”

) storage sequence, to identify an oldest arrival timestamp in the timestamp buffer in accordance with the FIFO storage sequence, to generate a timing report in response to an offset, and to record rate lock status in a log when the offset falls within a predefined range.

2. The network layout of claim 1, wherein the PSN is Internet and the first node is a router.

3. The network layout of claim 1, wherein the second node includes,

an egress component configured to send data streams based on an adjusted egress rate;

and

a jitter buffer coupled to the egress element and configured to temporarily store packets.

4. The network layout of claim 1, wherein the second node includes an ingress component coupled to the jitter buffer and coupled to the CES circuit for receiving data packets.

5. The network layout of claim 4, wherein the ingress component includes a monitor component configured to monitor incoming packets from the PSN.

6. The network layout of claim 5, wherein the ingress component includes a stamp generator coupled to the monitor component and configured to generate a timestamp each time a packet arrives.

7. The network layout of claim 6, wherein the ingress component includes an offset calculator coupled to the stamp generator and configured to calculate time difference between the arrival time of the most recent packet and arrival time of oldest packet stored in a timestamp buffer.

8. The network layout of claim 7, wherein the ingress component further includes a timing comparator coupled to the offset calculator and configured to provide a deviation or divergence value.

9. The network layout of claim 8, wherein the timing comparator compares the offset against a range of acceptable limits.

10. A method for broadcasting a possible transmission anomaly associated with a network circuit, comprising:

receiving a stream of data packets traveling across a circuit emulation service (“

CES”

) circuit;

generating parts per million (“

PPM”

) data representing an offset of the stream of data packets by comparing between arrival timestamp of the stream of data packets and a previously recorded timestamp;

logging an anomaly and raising alarm for transmission anomaly when the PPM data exceeds a predefined wander threshold;

obtaining an arrival timestamp associated with the stream of data packets and storing the arrival timestamp in a timestamp buffer based on a first-in first-out (“

FIFO”

) storage sequence;

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

generating a timing report in response to an offset; and

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

11. The method of claim 10, further comprising logging a message of lost rate lock when ingress rate is greater than a predefined ingress clock rate threshold.

12. The method of claim 11, further comprising logging a transmission anomaly when egress rate diverges in accordance with a predefined range.

13. The method of claim 10, further comprising sending a warning message when the offset falls outside of the range of predefined limits.

14. The method of claim 10, wherein receiving a stream of data packets includes receiving a recently arrived data packet traveling across a T1 carrier.

15. The method of claim 10, wherein receiving a stream of data packets includes receiving a recently arrived data packet traveling across an E1 carrier.

16. The method of claim 10, further comprising generating the recent timestamp at a time when the recently arrived data packet is received at a port of a network device.

17. A network device configured to broadcast a possible transmission anomaly associated with a network circuit, comprising:

ingress element configured to receive a stream of data packets traveling across a circuit emulation service (“

CES”

) circuit; and

a timing analyzer coupled to the ingress element and configured to generate parts per million (“

PPM”

) data representing an offset of the stream of data packets by comparing between arrival timestamp of the stream of data packets and a previously recorded timestamp and log an anomaly and raising alarm for transmission anomaly when the PPM data exceeds a predefined wander threshold, wherein the timing analyzer is further capable of obtaining an arrival timestamp associated with the stream of data packets and storing the arrival timestamp in a timestamp buffer based on a first-in first-out (“

FIFO”

) storage sequence, identifying an oldest arrival timestamp in the timestamp buffer in accordance with the FIFO storage sequence, generating a timing report in response to an offset and recording rate lock status in a log when the offset falls within a predefined range.

18. The network device of claim 17, further comprising an egress component configured to send data streams based on an adjusted egress rate.

19. The network device of claim 18, wherein the ingress component includes a monitor component configured to monitor incoming packets from the PSN.

20. The network device of claim 17, further comprising a jitter buffer coupled to the egress element and configured to temporarily store packets.