US-12621237-B2 - Fast and reliable inter-network element optical protection switching

US12621237B2US 12621237 B2US12621237 B2US 12621237B2US-12621237-B2

Abstract

Disclosed herein are optical networks and nodes, including a head-end node comprising a controller and a line module. The line module comprises a first processor and first memory storing instructions that when executed by the first processor cause the first processor to receive fault information, generate a fault packet and a fault trigger request that include a sequence number, a sequence reset time, and the fault information, and send the fault packet via a first network path and the fault trigger request via a second network path to the controller. The controller comprises a second processor, second memory storing second instructions, and packet forwarding circuitry configured to receive and automatically forward the fault packet to a tail-end optical node. The second instructions cause the second processor to receive the fault trigger request, process the fault trigger request, and send the fault trigger request to the tail end optical node.

Inventors

Dharmendra Kalita
Kapil Juneja
Ashok Kunjidhapatham
Pardeep Kumar Reddy Buyanni

Assignees

INFINERA CORP.

Dates

Publication Date: 20260505
Application Date: 20230905

Claims (7)

1 . A hybrid node, comprising: a node controller comprising a first processor, a first non-transitory processor-readable medium storing first processor-executable instructions, a first network switch configured to communicate using a first network path and a second network path, and packet forwarding circuitry forming a portion of the first network path; and; an optical protection switching module comprising a second processor, a second non-transitory processor-readable medium storing second processor-executable instructions, a stored sequence number, and a stored sequence reset time, a first line port connected to a working path, a second line port connected to a protection path, a system port, and an optical switch coupled to the first line port to receive first optical signals from the working path and the second line port to receive second optical signals from the protection path for selectively switching optical signals from the first line port or the second line port to the system port; and a digital line module comprising a third processor, a third non-transitory processor-readable medium storing third processor-executable instructions, and a second network switch configured to communicate using the first network path and the second network path; wherein the third processor-executable instruction, when executed by the third processor, cause the third processor to: receive a fault signal including fault information related to a fault; generate a first fault packet comprising a first packet header and the fault information, the first packet header including a first sequence number and a first sequence reset time; generate a first fault trigger request comprising first request parameters and the fault information, the first request parameters including the first sequence number and the first sequence reset time; and send the first fault packet and the first fault trigger request to the node controller, the first fault packet sent via the first network path and the first fault trigger request sent via the second network path; and wherein the packet forwarding circuitry of the node controller is configured to: receive the first fault packet and automatically forward the first fault packet to the optical protection switching module; and wherein the first processor-executable instructions, when executed, cause the first processor of the node controller to receive the first fault trigger request, process the first fault trigger request, and send the first fault trigger request to the optical protection switching module; wherein the second processor-executable instructions, when executed by the second processor, cause the second processor to: receive, at a first instant in time, the first fault packet and process the first fault packet by comparing the first sequence number and the first sequence reset time to the stored sequence number and the stored sequence reset time stored in the second non-transitory processor-readable medium and, if the first sequence number is greater than the stored sequence number and the first sequence reset time is equal to the stored sequence reset time, replace the stored sequence number with the first sequence number and the stored sequence rest time with the first sequence reset time in the second non-transitory processor-readable medium and switch the first line port or the second line port to the system port on the optical switch based on the fault information; and receive, at a second instant in time later than the first instant in time, the processed first fault trigger request and further process the processed first fault trigger request by comparing the first sequence number and the first sequence reset time to the stored sequence number and the stored sequence reset time stored in the second non-transitory processor-readable medium and, if the first sequence number is equal to the stored sequence number and the first sequence reset time is equal to the stored sequence reset time number, discard the fault information of the first fault trigger request.
2 . The hybrid node of claim 1 , wherein the first network path is a first virtual local area network, and the second network path is a second virtual local area network.
3 . The hybrid node of claim 1 , wherein the packet forwarding circuitry is a field programmable gate array configured to receive and automatically forward the first fault packet.
4 . The hybrid node of claim 1 , wherein the first packet header further comprises first packet forwarding information identifying the optical protection switching module as a destination, and wherein the packet forwarding circuitry uses the first packet forwarding information to automatically forward the first fault packet to the optical protection switching module.
5 . The hybrid node of claim 1 , wherein the third processor-executable instructions further comprise a first digital trigger application that, when executed by the third processor, causes the third processor to generate the first fault trigger request comprising the request parameters and the fault information; and send the first fault trigger request via the second network path to the node controller.
6 . The hybrid node of claim 5 , wherein the first digital trigger application causes the third processor to generate request parameters further including a nodeID identifying the optical protection switching module as a destination for the fault trigger request.
7 . The hybrid node of claim 6 , wherein the second processor-executable instructions further comprise a second digital trigger application that, when executed by the second processor, causes the second processor to receive and process the first fault trigger request, wherein processing the first fault trigger request includes forwarding, based on the nodeID, the first fault trigger request to the optical protection switching module.

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Patent Application No. 63/403,639, which was filed on Sep. 2, 2022, the contents of which are incorporated herein by reference in their entirety. BACKGROUND Communication networks, in particular fiber optics networks, are subject to a wide variety of failures caused by natural disasters, wear out, patch-cable cuts and so on. Such failures may affect network functionalities such as data transmission and reception. To circumvent these drawbacks, most fiber optics networks use channel protection schemes for its optical layer. As soon as a failure in the network is detected, these channel protection schemes may divert the affected traffic to another fault-free path in the network. For example, under a fault-free condition, the traffic is transported along a working path. However, if a failure is detected on that path, the channel protection scheme may switch the traffic to a protecting path that was not affected by the failure. Current protection schemes at optical layers are similar to protection schemes at digital layers. Specifically, both working and protecting paths are simultaneously monitored for failure, and in case of a network failure, an Automatic Protection Switching (APS) selects a healthier channel from which to source traffic. Although current protection schemes may satisfy sub-50 millisecond requirements for traffic recovery, they are costly to implement. Thus, it would be desirable to have a method and apparatus that provides sub-50 millisecond traffic recovery time (protection switching time) without costly implementation. Conventionally, software-based forwarding has been used in networks requiring inter-domain packet forwarding. While software-based forwarding has proven reliable, lowering the fault relay time has been difficult, especially when a fault source and destination are hosted on different nodes and/or are situated on different network layers (e.g., a fault source in a digital layer (Layer-1) and a destination in an optical layer (Layer-0)). SUMMARY The systems and methods described herein solve these and other problems by providing fault propagation via both a fast path (hardware-assisted digital fault relay) that significantly reduces fault relay time, which, in turn reduces the traffic recovery time and a slow path (software-based digital fault relay) that ensures reliability. In one aspect, in accordance with some implementations, the specification describes methods and systems including a head-end node, comprising: a node controller comprising a first processor, a first non-transitory processor-readable medium storing first processor-executable instructions, a first network switch configured to communicate using a first network path and a second network path, and packet forwarding circuitry forming a portion of the first network path; and a digital line module comprising a second processor, a second non-transitory processor-readable medium storing second processor-executable instructions, and a second network switch configured to communicate using the first communication network and the second communication network; wherein the second processor-executable instructions, when executed by the second processor, cause the second processor to: receive fault information related to a fault; generate a fault packet comprising a packet header and the fault information, the packet header including a first sequence number and a first sequence reset time; generate a fault trigger request comprising request parameters and the fault information, the request parameters including the first sequence number and the first sequence reset time; and send the fault packet and the fault trigger request to the node controller, the fault packet sent via the first network path and the fault trigger request sent via the second network path; and wherein the packet forwarding circuitry of the node controller is configured to: receive the fault packet and automatically forward the fault packet to a third network switch of a second node controller of a tail-end optical node; and wherein the first processor-executable instructions, when executed, cause the first processor of the node controller to receive the fault trigger request, process the fault trigger request, and send the fault trigger request to a third processor of the tail end optical node. In another aspect, in accordance with some implementations, the specification describes methods and systems including a tail-end optical node, comprising: an optical protection switching module comprising a first processor, a first non-transitory processor-readable medium storing first processor-executable instructions, a stored sequence number, and a stored sequence reset time, a first line port connected to a working path, a second line port connected to a protection path, a system port, and an optical switch coupled to the first line port to receive first optical sign