Optical communication system and master station

Patent metadata

Field	Value
Publication number	US-11973531-B2
Application number	US-202017916789-A
Country	US
Kind code	B2
Filing date	Apr 9, 2020
Priority date	Apr 9, 2020
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

The present invention enables shortening the time required for resuming communication in a protection method that uses a backup path in an optical communication system that includes a master station device and multiple slave station devices. The slave station devices are connected to a loop path in parallel. The communication paths between the master station device and the slave station devices include a normal path and a backup path. The master station device executes communication control processing with respect to the slave station devices based on the RTTs. A first slave station device is a slave station device that cannot perform communication via the normal path. If the first slave station device is detected, the master station device calculates a first backup path for the first slave station device based on a first RTT between the master station device and the loop path, a loop RTT required for one full lap on the loop path, and the first normal path RTT for the first slave station device. The master station device then resumes communication control processing for the first slave station device based on the calculated first backup path RTT.

First claim

The invention claimed is:

1. An optical communication system comprising:
a plurality of slave station devices that are connected to a loop path in parallel; and
a master station device that is connected to the loop path and configured to perform communication with each of the slave station devices,
wherein communication paths between the master station device and each of the slave station devices include:
a normal path that extends along the loop path from the master station device to each of the slave station devices in a first direction, and
a backup path that extends along the loop path from the master station device to each of the slave station devices in a second direction that is opposite to the first direction,

the master station device is configured to execute communication control processing for controlling communication with each of the slave station devices based on an RTT (Round Trip Time) between the master station device and the slave station device,
a normal path RTT is the RTT in a case of communication performed via the normal path,
a backup path RTT is the RTT in a case of communication performed via the backup path,
a first slave station device is a slave station device that cannot perform communication via the normal path, among the plurality of slave station devices,
a first normal path RTT is the normal path RTT between the master station device and the first slave station device,
a first backup path RTT is the backup path RTT between the master station device and the first slave station device,
a first RTT is the RTT between the master station device and the loop path,
a loop RTT is the RTT required for one full lap on the loop path,
the master station device holds the normal path RTT for each of the slave station devices, the first RTT, and the loop RTT,
if the first slave station device does not exist, the master station device executes the communication control processing with respect to the slave station devices based on the normal path RTTs, and
if the first slave station device is detected, the master station device calculates the first backup path RTT based on the first RTT, the loop RTT, and the first normal path RTT, and resumes the communication control processing with respect to the first slave station device based on the calculated first backup path RTT.

2. The optical communication system according to claim 1 ,
wherein letting the first RTT, the loop RTT, and the first normal path RTT respectively be expressed as T_trunk, T_loop, and Tj_normal,
the master station device calculates 2×T_trunk+T_loop−Tj_normal as the first backup path RTT.

3. The optical communication system according to claim 1 ,
wherein if the first slave station device does not exist, the master station device disables the backup path, and
if the first slave station device is detected, the master station device enables the backup path.

4. A master station device that performs communication with each of a plurality of slave station devices in an optical communication system,
wherein the slave station devices are connected to a loop path in parallel,
communication paths between the master station device and each of the slave station devices include:
a normal path that extends along the loop path from the master station device to each of the slave station devices in a first direction, and
a backup path that extends along the loop path from the master station device to each of the slave station devices in a second direction that is opposite to the first direction,

the master station device is configured to execute communication control processing for controlling communication with each of the slave station devices based on an RTT (Round Trip Time) between the master station device and the slave station device,
a normal path RTT is the RTT in a case of communication performed via the normal path,
a backup path RTT is the RTT in a case of communication performed via the backup path,
a first slave station device is a slave station device that cannot perform communication via the normal path, among the plurality of slave station devices,
a first normal path RTT is the normal path RTT between the master station device and the first slave station device,
a first backup path RTT is the backup path RTT between the master station device and the first slave station device,
a first RTT is the RTT between the master station device and the loop path,
a loop RTT is the RTT required for one full lap on the loop path,
the master station device holds the normal path RTT for each of the slave station devices, the first RTT, and the loop RTT,
if the first slave station device does not exist, the master station device executes the communication control processing with respect to the slave station devices based on the normal path RTTs, and
if the first slave station device is detected, the master station device calculates the first backup path RTT based on the first RTT, the loop RTT, and the first normal path RTT, and resumes the communication control processing with respect to the first slave station device based on the calculated first backup path RTT.

Assignees

• Nippon Telegraph & Telephone

Inventors

• HARADA Rintaro
• Ujikawa Hirotaka
• Kaneko Shin
• Terada Jun

Classifications

• H04B10/032 Primary

  using working and protection systems {(H04J14/0287 takes precedence)} · CPC title

• H04B10/272 Primary

  Star-type networks {or tree-type networks} · CPC title

• H04J14/08

  Time-division multiplex systems · CPC title

• H04B10/0791

  Fault location on the transmission path · CPC title

• H04J14/0282

  WDM tree architectures · CPC title