# US 10,932,018 B2 · Method for removing static differential delays between signals transported over an optical transport network

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- Number: US 10,932,018 B2
- Document ID: US10932018B2
- Status: Granted
- Kind: B2
- Application number: 16/694,654
- Filed: 2019-11-25
- Published: 2020-07-09
- Granted: 2021-02-23
- Earliest claimed: 2019-01-04
- Assignees: ADVA Optical Networking SE
- Applicants: ADVA Optical Networking SE
- Inventors: Oliver Bleck
- Web page: https://patentgrep.com/patent/US10932018B2

## CPC

- H04Q 11/0067: {Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring}
- H04J 3/1652: {Optical Transport Network [OTN]}
- H04J 2203/0066: Signalling, e.g. protocols, reference model
- H04Q 2011/0088: {Signalling aspects}
- H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W)
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)

## Abstract

A method for removing static differential delays resulting from an independent transport of the client signals of a client signal bundle through an optical transport network, OTN, which comprises OTN mappers mapping received client signals to ODU signals transported to OTN demappers demapping received ODU signals to client signals, wherein a process slave, PS, at the OTN mapper end of said OTN network supplies continuously or in response to a received request information about timing relations between the client signals of said client signal bundle to a process master, PM, at the OTN demapper end of said OTN network used by the process master, PM, to remove the static differential delays between the client signals of the respective client signal bundle.

## Claims

### Claim 1

A method for removing static differential delays resulting from an independent transport of the client signals, CS, of a client signal bundle, CSB, through an optical transport network, OTN, which comprises OTN mappers mapping received client signals to ODU signals transported to OTN demappers demapping received ODU signals to client signals, CS,
wherein a process slave, PS, at the OTN mapper end of said OTN network supplies continuously or in response to a received request information about timing relations between the client signals, CS, of said client signal bundle, CSB, to a process master, PM, at the OTN demapper end of said OTN network used by the process master, PM, to remove the static differential delays between the client signals, CS, of the respective client signal bundle, CSB.

### Claim 2 (depends on 1)

The method according to claim 1 wherein the process master, PM, at the OTN demapper end of said OTN network generates a deskew request, REQ, communicated by the process master, PM, at the OTN demapper end of said OTN network to the process slave, PS, at the OTN mapper end of said OTN network.

### Claim 3 (depends on 2)

The method according to claim 2 wherein the process slave, PS, at the OTN mapper end of said OTN network provides in response to the deskew request, REQ, received from the process master, PM, at the OTN demapper end of said OTN network an acknowledgement, ACK, comprising information about timing relations between alignment markers, AM, associated with the client signals, CS, of the client signal bundle, CSB, communicated by said process slave, PS, to said process master, PM.

### Claim 4 (depends on 3)

The method according to claim 3, wherein the static differential delays between the client signals, CS, of the respective client signal bundle, CSB, are removed by the process master, PM, in response to the received acknowledgement, ACK, on the basis of the timing relation between the alignment markers, AM.

### Claim 5 (depends on 2)

The method according to claim 2 wherein the generation of the deskew request, REQ, by the process master, PM, at the OTN demapper end of said OTN network is triggered autonomously by an event detected at the OTN demapper end of said OTN network or triggered by a user request.

### Claim 6 (depends on 2)

The method according to claim 2 wherein the process master, PM, at the OTN demapper end of said OTN network stops sending the deskew request, REQ, after the removal of the static differential delays has been performed by the process master, PM.

### Claim 7 (depends on 1)

The method according to claim 1 wherein the client signals, CS, form part of a configured client signal bundle, CSB, identified by a bundle identifier, BID, carried in the deskew request, REQ.

### Claim 8 (depends on 3)

The method according to claim 3 wherein the process slave, PS, provides the acknowledgement, ACK, if the received deskew request, REQ, has been determined by the process slave, PS, to form a valid deskew request, REQ.

### Claim 9 (depends on 1)

The method according to claim 1 wherein the process master, PM, disables transport of client signals, CS, forming part of the respective client signal bundle, CSB, as long as the acknowledgement, ACK, is received by the process master, PM.

### Claim 10 (depends on 2)

The method according to claim 2 wherein alignment markers, AM, forming part of the mapped ODU signals are synchronized to each other by the process slave, PS, in response to the received deskew request, REQ, before the acknowledgement, ACK, is provided by the process slave, PS, to said process master, PM.

### Claim 11 (depends on 10)

The method according to claim 10 wherein the alignment markers, AM, comprise Frame Start Signal, FS, markers and/or a MultiFrame Start Signal, MFS, markers.

### Claim 12 (depends on 1)

The method according to claim 1 wherein timing relations between the alignment markers, AM, of all client signals, CS, of a client signal bundle, CSB, mapped by the OTN mapper are determined by the process slave, PS, at the mapper end of the OTN network in response to a valid deskew request, REQ, received from the process master, PM, at the demapper end of said OTN network to generate a timing relation snapshot communicated by the process slave, PS, along with the acknowledgement, ACK, to the process master, PM, used to remove static differential delays between the respective client signals, CS.

### Claim 13 (depends on 12)

The method according to claim 12 wherein the process slave, PS, at the OTN mapper end of said OTN network further communicates a deskew frame counter value to the process master, PM, at the OTN demapper end of said OTN network inserted in the ODU signals transporting a mapped client signal, CS, of the respective client signal bundle, CSB, to the OTN demapper of said OTN network.

### Claim 14 (depends on 1)

The method according to claim 1 wherein portions of the client signals, CS, of the respective client signal bundle, CSB, are replaced before being mapped by the OTN mapper by the process slave, PS, at the OTN mapper end of said OTN network by inserted synchronized cyclically repeated alignment markers, AM, in response to a valid deskew request, REQ, received from the process master, PM, at the demapper end of said OTN network to establish identifiable timing relations between the client signals, CS, of the respective client signal bundle, CSB, used by the process master, PM, to remove static differential delays between the respective client signals, CS.

### Claim 15 (depends on 1)

The method according to claim 1 wherein before mapping by the OTN mapper by the process slave, PS, at the mapper end of said OTN network regardless of receiving a valid deskew request, REQ, or not synchronized cyclically repeated alignment markers, AM, are inserted in addition to the data to establish identifiable timing relations between the client signals, CS, of the respective client signal bundle, CSB, used by the process master, PM, to remove static differential delays between the respective client signals, CS.

### Claim 16 (depends on 2)

The method according to claim 2 wherein the deskew request, REQ, and the acknowledgement, ACK, are transported between the process master, PM, at the OTN demapper end of said OTN network and the process slave, PS, at the OTN mapper end of said OTN network in a communication channel using allocated bytes of the OPU overheads, the ODU overheads and/or the OTU overheads.

### Claim 17 (depends on 1)

The method according to claim 1 wherein the client signals, CS, are provided by a client equipment comprising a signal switch or a signal router.

### Claim 18

An optical transport network, OTN, comprising
OTN mappers adapted to map received client signals, CS, of a client signal bundle, CSB, to ODU signals transported to OTN demappers of said OTN network adapted to demap received ODU signals to client signals, CS,
wherein a process slave, PS, at the OTN mapper end of said OTN network is configured to supply continuously or in response to a received request, REQ, information about timing relations between the client signals, CS, of said client signal bundle, CSB, to a process master, PM, at the OTN demapper end of said OTN network used by the process master, PM, to remove static differential delays between the client signals, CS, of the respective client signal bundle, CSB.

### Claim 19 (depends on 18)

The optical transport network, OTN, according to claim 18 wherein the client signals, CS, are provided by client equipment of said OTN network.