Time synchronization path selection device and time synchronization path selection method

Patent metadata

Field	Value
Publication number	US-11722288-B2
Application number	US-201917413863-A
Country	US
Kind code	B2
Filing date	Dec 6, 2019
Priority date	Dec 17, 2018
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

[Problem to be Solved] Optimizing a route of time synchronization in a network including apparatuses with different types of precision classes.[Solution to the Problem] A time transmission system includes BC nodes 200 with different types of apparatus performances, and multiple routes of PTP packets from GM nodes 101 and 102 to a BC node 220 via the BC node 200 are present. Each BC node 200 located upstream on a route performs notification of performance information indicating its apparatus performance to the BC node 200 located downstream with respect thereto. The BC node 220 includes a determination index calculation unit 11 that calculates a determination index for each route by referencing the performance information notified from the BC nodes 200 located upstream on each route, and a route selection unit 12 that selects a route for transmitting and receiving PTP packets from multiple routes of PTP packets to the BC node 220, based on the calculated determination index for each route.

First claim

The invention claimed is:

1. A time synchronization route selection apparatus having a function of a time synchronization apparatus used in a time transmission system in which time synchronization packets are transmitted and received by time synchronization apparatuses, and times of the time synchronization apparatuses are synchronized based on time information of transmission and reception, wherein in the time transmission system, the time synchronization apparatuses having different types of apparatus performances are included, and a plurality of routes of the time synchronization packets from a time reference apparatus to the time synchronization route selection apparatus via the time synchronization apparatuses are present, each time synchronization apparatus located upstream on each route performs notification of performance information indicating an apparatus performance of the time synchronization apparatus to a time synchronization apparatus located downstream with respect thereto, and the time synchronization route selection apparatus includes:
a determination index calculation unit, including one or more processors, configured to calculate a determination index for each route by referencing the performance information notified from the time synchronization apparatuses located upstream on the route, wherein the determination index calculation unit is configured to:
use precision classes registered in advance in the time synchronization apparatuses as the performance information notified from the time synchronization apparatuses, and
calculate the determination index for each route based on a spec value defined for each precision class, and a number of time synchronization apparatuses corresponding to the spec value; and

a route selection unit, including one or more processors, configured to, based on the calculated determination index for each route, select a route for transmitting and receiving the time synchronization packets from a plurality of routes of the time synchronization packets to the time synchronization route selection apparatus.

2. The time synchronization route selection apparatus according to claim 1 , wherein each of the time synchronization apparatuses is configured to perform notification of the performance information of the time synchronization apparatus and performance information of each time synchronization apparatus located upstream of the time synchronization apparatus to a time synchronization apparatus located downstream, which is a direct transmission and reception partner for the time synchronization packets.

3. The time synchronization route selection apparatus according to claim 1 , wherein each of the time synchronization apparatuses is configured to cause the performance information to be distributed from a management apparatus, which is an apparatus separate from the time synchronization apparatus, to downstream time synchronization apparatuses by notifying the management apparatus of the performance information of the time synchronization apparatus.

4. A time synchronization route selection apparatus having a function of a time synchronization apparatus used in a time transmission system in which time synchronization packets are transmitted and received by time synchronization apparatuses, and times of the time synchronization apparatuses are synchronized based on time information of transmission and reception, wherein in the time transmission system, the time synchronization apparatuses having different types of apparatus performances are included, and a plurality of routes of the time synchronization packets from a time reference apparatus to the time synchronization route selection apparatus via the time synchronization apparatuses are present, each time synchronization apparatus located upstream on each route performs notification of performance information indicating an apparatus performance of the time synchronization apparatus to a time synchronization apparatus located downstream with respect thereto, and the time synchronization route selection apparatus includes:
a determination index calculation unit, including one or more processors, configured to calculate a determination index for each route by referencing the performance information notified from the time synchronization apparatuses located upstream on the route, wherein the determination index calculation unit is configured to calculate the determination index for each route using, as the performance information notified from each of the time synchronization apparatuses, a time difference value between a measured value of time information resulting from the time synchronization apparatus performing time synchronization with the time synchronization apparatus upstream of the time synchronization apparatus and a measured value of time information obtained when performing time synchronization with the time synchronization apparatus downstream of the time synchronization apparatus; and
a route selection unit, including one or more processors, configured to, based on the calculated determination index for each route, select a route for transmitting and receiving the time synchronization packets from a plurality of routes of the time synchronization packets to the time synchronization route selection apparatus.

5. A time synchronization route selection method to be executed by a time synchronization route selection apparatus having a function of a time synchronization apparatus used in a time transmission system in which time synchronization packets are transmitted and received by time synchronization apparatuses, and times of the time synchronization apparatuses are synchronized based on time information of transmission and reception, wherein in the time transmission system, the time synchronization apparatuses having different types of apparatus performances are included, and a plurality of routes of the time synchronization packets from a time reference apparatus to the time synchronization route selection apparatus via the time synchronization apparatuses are present, each time synchronization apparatus located upstream on each route performs notification of performance information indicating an apparatus performance of the time synchronization apparatus to a time synchronization apparatus located downstream with respect thereto, the time synchronization route selection apparatus includes a determination index calculation unit including one or more processors and a route selection unit including one or more processors, the time synchronization route selection method comprising:
calculating, by the determination index calculation unit, a determination index for each route by referencing the performance information notified from each time synchronization apparatus located upstream on the route, and based on the calculated determination index for each route, wherein calculating the determination index comprises:
using, by the determination index calculation unit, precision classes registered in advance in the time synchronization apparatuses as the performance information notified from the time synchronization apparatuses, and
calculating, by the determination index calculation unit, the determination index for each route based on a spec value defined for each precision class, and a number of time synchronization apparatuses corresponding to the spec value; and

selecting, by the route selection unit, a route for transmitting and receiving the time synchronization packets from a plurality of routes of the time synchronization packets to the time synchronization route selection apparatus.

6. The time synchronization route selection method according to claim 5 , wherein each of the time synchronization apparatuses is configured to perform notification of the performance information of the time synchronizat

Assignees

• Nippon Telegraph & Telephone

Inventors

• Arai Kaoru
• Sakuma Hiroki
• Nakagawa Masahiro
• Tsuboi Shunichi

Classifications

• H04L7/0016 Primary

  correction of synchronization errors · CPC title

• H04J3/0679

  by determining clock distribution path in a network · CPC title

• H04W40/02

  Communication route or path selection, e.g. power-based or shortest path routing · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04J3/0641

  Change of the master or reference, e.g. take-over or failure of the master · CPC title