Time transfer systems and methods over flexible ethernet

Patent metadata

Field	Value
Publication number	US-10097480-B2
Application number	US-201514868603-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 29, 2015
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

Time transfer systems and methods in Flexible Ethernet (FlexE) between a first node and a second node include detecting a timestamp point of reference in FlexE overhead and sampling a time based thereon; communicating samples of the timestamp point of reference between the first node and the second node; and determining a time delay between the first node and the second node based on the samples.

First claim

What is claimed is:

1. A time transfer method in Flexible Ethernet (FlexE) between a first node and a second node, the time transfer method comprising:
detecting a timestamp point of reference in FlexE overhead comprising one of a boundary, a toggling bit or pattern, and a specific bit pattern, and sampling time based on detecting the timestamp point of reference, wherein the FlexE overhead is encoded as a 66b block and inserted on each PHY of a FlexE group;
communicating samples of the time between the first node and the second node in the FlexE overhead; and
determining a time delay between the first node and the second node based on the samples of the time.

2. The time transfer method of claim 1 , wherein the timestamp point of reference is one of a frame and multiframe boundary associated with FlexE frames.

3. The time transfer method of claim 1 , wherein the timestamp point of reference is a toggling bit or pattern in the FlexE overhead.

4. The time transfer method of claim 1 , wherein the timestamp point of reference is determined post processing in a transmit direction and pre processing in a receive direction.

5. The time transfer method of claim 1 , wherein the communicating uses a reserved area in the FlexE overhead.

6. The time transfer method of claim 1 , wherein the communicating uses an existing management channel in the FlexE overhead.

7. The time transfer method of claim 1 , wherein the samples comprise T A-B which is an arrival time in a receive direction at the second node, T D-A which is a departure time in a transmit direction at the first node, T A-A which is an arrival time in a receive direction at the first node, and T D-B which is a departure time in a transmit direction at the second node,
wherein a Round Trip Delay is [(T A-B −T D-A )+(T A-A −T D-B )],
wherein a time delay TD is RTD/2, and
wherein a time error at the second node relative to the first node is T A-B −(T D-A +TD).

8. The time transfer method of claim 1 , wherein the time transfer method is compliant to IEEE 1588 and performed in a FlexE shim.

9. A node configured to switch a Flexible Ethernet (FlexE) client service in a network, the node comprising:
circuitry configured to detect a timestamp point of reference in FlexE overhead comprising one of a boundary, a toggling bit or pattern, and a specific bit pattern, and to sample time based on detection of the timestamp point of reference, wherein the FlexE overhead is encoded as a 66b block and inserted on each PHY of a FlexE group;
circuitry configured to communicate samples of the time, with a second node, in the FlexE overhead; and
circuitry configured to determine a time delay to the second node based on the samples of the time.

10. The node of claim 9 , wherein the timestamp point of reference is one of a frame and multiframe boundary associated with FlexE frames.

11. The node of claim 9 , wherein the timestamp point of reference is a toggling bit in the FlexE overhead.

12. The node of claim 9 , wherein the timestamp point of reference is determined post processing in a transmit direction and pre processing in a receive direction.

13. The node of claim 9 , wherein the circuitry configured to communicate uses a reserved area in the FlexE overhead.

14. The node of claim 9 , wherein the circuitry configured to communicate uses an existing management channel in the FlexE overhead.

15. The node of claim 9 , wherein the samples comprise T A-B which is an arrival time in a receive direction at the second node, T D-A which is a departure time in a transmit direction at the first node, T A-A which is an arrival time in a receive direction at the first node, and T D-B which is a departure time in a transmit direction at the second node,
wherein a Round Trip Delay is [(T A-B −T D-A )+(T A-A −T D-B )],
wherein a time delay TD is RTD/2, and
wherein a time error at the second node relative to the first node is T A-B −(T D-A +TD).

16. The node of claim 9 , wherein the time transfer method is compliant to IEEE 1588 and performed in a FlexE shim.

17. A node utilizing Flexible Ethernet (FlexE) and configured to determine time transfer to a second node, the node comprising:
circuitry configured to obtain a first time sample from the second node based on a first timestamp point of reference in FlexE overhead detected at the second node, wherein the FlexE overhead is encoded as a 66b block and inserted on each PHY of a FlexE group;
circuitry configured to detect a second time sample based on a second timestamp point of reference in the FlexE overhead, wherein the first timestamp point of reference and the second timestamp point of reference comprise one of a boundary, a toggling bit or pattern, and a specific bit pattern in the FlexE overhead; and
circuitry configured to determine a time delay to the second node based on the first time sample and the second time sample.

18. The node of claim 17 , wherein the first timestamp point of reference and the second timestamp point of reference are one of a frame and multiframe boundary associated with FlexE frames.

19. The node of claim 17 , wherein the first timestamp point of reference and the second timestamp point of reference are a toggling bit in the FlexE overhead.

20. The node of claim 17 , wherein a timestamp point of reference is determined post processing in a transmit direction and pre processing in a receive direction.

Assignees

• Ciena Corp

Inventors

• Gareau Sebastien
• Leclair Marc

Classifications

• H04L43/106

  using time related information in packets, e.g. by adding timestamps · CPC title

• H04L49/35 Primary

  Switches specially adapted for specific applications · CPC title

• H04L43/0864

  Round trip delays · CPC title

• H04J3/1652

  Optical Transport Network [OTN] · CPC title

• H04J3/065 Primary

  using timestamps · CPC title