# US 2019/0173579 A1 · Reachability determination in wavelength division multiplexing network based upon fiber loss measurements

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- Number: US 2019/0173579 A1
- Document ID: US20190173579A1
- Status: Published application
- Kind: A1
- Application number: 16/267,229
- Filed: 2019-02-04
- Published: 2019-06-06
- Earliest claimed: 2017-06-14
- Assignees: AT&T Intellectual Property I, L.P.
- Applicants: AT&T Intellectual Property I, L.P.
- Inventors: Sheryl Woodward; Kathleen Tse; Martin Birk; Angela Chiu; Balagangadhar Bathula
- Web page: https://patentgrep.com/patent/US20190173579A1

## CPC

- H04B 10/07953: {Monitoring or measuring OSNR, BER or Q}
- H04B 10/071: using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
- H04B 10/07957: {Monitoring or measuring wavelength}
- H04B 10/2507: for the reduction or elimination of distortion or dispersion
- H04J 14/02122: {Colourless, directionless or contentionless [CDC] arrangements}
- H04J 14/0257: {Wavelength assignment algorithms}
- H04J 14/0271: {Impairment aware routing}
- H04Q 11/00: Selecting arrangements for multiplex systems (multiplex systems H04J)
- H04Q 11/0001: {using optical switching}
- H04Q 11/0066: {Provisions for optical burst or packet networks}
- H04Q 2011/0073: {Provisions for forwarding or routing, e.g. lookup tables}
- H04Q 2011/0083: {Testing; Monitoring}
- H04Q 2011/0086: {Network resource allocation, dimensioning or optimisation}
- H04B: TRANSMISSION
- 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)
- H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W)

## Abstract

Devices, computer-readable media and methods are disclosed for determining reachability for a wavelength connection in a telecommunication network. For example, a processor deployed in a telecommunication network may calculate a fiber loss on a link in the telecommunication network using optical power measurements and determine that a destination node of a wavelength connection is not reachable via a path that includes the link based upon the fiber loss of the link that is calculated. In one example, the determining is based upon a number of links in the path, an effective fiber loss for each link in the path, a penalty for nodes in the path, and an acceptable loss value. The processor may further perform a remedial action in response to determining that the destination node of the wavelength connection is not reachable via the path.

## Claims

### Claim 1

A device comprising:
a processor deployed in a telecommunication network; and
a computer-readable medium storing instructions which, when executed by the processor, cause the processor to perform operations, the operations comprising:
receiving a request to establish a wavelength connection between a first node and a second node in the telecommunication network, the request including information on an expected duration of the wavelength connection;
determining whether the second node is reachable from the first node using an acceptable loss value, wherein the acceptable loss value is based upon the expected duration of the wavelength connection; and
configuring the telecommunication network based upon whether the second node is determined to be reachable from the first node.

### Claim 2 (depends on 1)

The device of claim 1, wherein a reduced acceptable loss value is utilized when the request is for a persistent wavelength connection as compared to an acceptable loss value that is utilized when the request is for a non-persistent wavelength connection.

### Claim 3 (depends on 1)

The device of claim 1, wherein the determining is based upon:
a number of links in the path;
an effective fiber loss for each link in the path;
a penalty for nodes in the path; and
the acceptable loss value.

### Claim 4 (depends on 3)

The device of claim 3, wherein the determining is based upon:
∥10×[log10{Σi=1n(1/li)}]∥+(n−1)h≤∥R∥
where n is the number of links in the path, li is the effective fiber loss for each link i, h is the penalty for nodes in the path, and R is the acceptable loss value.

### Claim 5 (depends on 3)

The device of claim 3, wherein the determining is based upon:
∥10×[log10{Σi=1n(1/li)}]∥+mhAMP+(n−1)hROADM≤∥R∥
where n is the number of links in the path, li is the effective fiber loss for each link i, m is a number of amplifiers in the path, hAMP is a loss for optical amplifiers in the path, hROADM is a loss for reconfigurable optical add-drop multiplexers in the path, and R is the acceptable loss value.

### Claim 6 (depends on 3)

The device of claim 3, wherein the effective fiber loss for each link is specific to a wavelength of the wavelength connection.

### Claim 7 (depends on 1)

The device of claim 1, wherein the acceptable loss value is based on an end of life acceptable loss for a single link and a margin.

### Claim 8

A method comprising:
receiving, by a processor deployed in a telecommunication network, a request to establish a wavelength connection between a first node and a second node in the telecommunication network, the request including information on an expected duration of the wavelength connection;
determining, by the processor, whether the second node is reachable from the first node using an acceptable loss value, wherein the acceptable loss value is based upon the expected duration of the wavelength connection; and
configuring, by the processor, the telecommunication network based upon whether the second node is determined to be reachable from the first node.

### Claim 9 (depends on 8)

The method of claim 8, wherein a reduced acceptable loss value is utilized when the request is for a persistent wavelength connection as compared to an acceptable loss value that is utilized when the request is for a non-persistent wavelength connection.

### Claim 10 (depends on 8)

The method of claim 8, wherein the determining is based upon:
a number of links in the path;
an effective fiber loss for each link in the path;
a penalty for nodes in the path; and
the acceptable loss value.

### Claim 11 (depends on 10)

The method of claim 10, wherein the determining is based upon:
∥10×[log10{Σi=1n(1/li)}]∥+(n−1)h≤∥R∥
where n is the number of links in the path, li is the effective fiber loss for each link i, h is the penalty for nodes in the path, and R is the acceptable loss value.

### Claim 12 (depends on 10)

The method of claim 10, wherein the determining is based upon:
∥10×[log10{Σi=1n(1/li)}]∥+mhAMP+(n−1)hROADM≤∥R∥
where n is the number of links in the path, li is the effective fiber loss for each link i, m is a number of amplifiers in the path, hAMP is a loss for optical amplifiers in the path, hROADM is a loss for reconfigurable optical add-drop multiplexers in the path, and R is the acceptable loss value.

### Claim 13 (depends on 10)

The method of claim 10, wherein the effective fiber loss for each link is specific to a wavelength of the wavelength connection.

### Claim 14 (depends on 8)

The method of claim 8, wherein the acceptable loss value is based on an end of life acceptable loss for a single link and a margin.

### Claim 15

A non-transitory computer-readable medium storing instructions which, when executed by a processor deployed in a telecommunication network, cause the processor to perform operations, the operations comprising:
receiving a request to establish a wavelength connection between a first node and a second node in the telecommunication network, the request including information on an expected duration of the wavelength connection;
determining whether the second node is reachable from the first node using an acceptable loss value, wherein the acceptable loss value is based upon the expected duration of the wavelength connection; and
configuring the telecommunication network based upon whether the second node is determined to be reachable from the first node.

### Claim 16 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein a reduced acceptable loss value is utilized when the request is for a persistent wavelength connection as compared to an acceptable loss value that is utilized when the request is for a non-persistent wavelength connection.

### Claim 17 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the determining is based upon:
a number of links in the path;
an effective fiber loss for each link in the path;
a penalty for nodes in the path; and
the acceptable loss value.

### Claim 18 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the determining is based upon:
∥10×[log10{Σi=1n(1/li)}]∥+(n−1)h≤∥R∥
where n is the number of links in the path, li is the effective fiber loss for each link i, h is the penalty for nodes in the path, and R is the acceptable loss value.

### Claim 19 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the determining is based upon:
∥10×[log10{Σi=1n(1/li)}]∥+mhAMP+(n−1)hROADM≤∥R∥
where n is the number of links in the path, li is the effective fiber loss for each link i, m is a number of amplifiers in the path, hAMP is a loss for optical amplifiers in the path, hROADM is a loss for reconfigurable optical add-drop multiplexers in the path, and R is the acceptable loss value.

### Claim 20 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the effective fiber loss for each link is specific to a wavelength of the wavelength connection.