PON Backup Link Mutual Protection and Fault Diagnosis

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Solution Overview

Problem

Existing PON systems face high construction costs, low bandwidth utilization, and inability to locate faults due to the need for redundant equipment and idle backup channels, which complicates service protection and fault diagnosis.

Innovation Solution

A PON system with a backup link between ONU/ONT equipment, managed by the OLT, allowing for mutual protection and fault diagnosis without additional redundant equipment, improving network security and bandwidth utilization by using a backup link for data transfer without affecting the secondary equipment's services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fully-protected optical fiber switchover with redundant equipment is implemented, then service protection capability is improved, but construction cost increases dramatically

Engineering Contradiction:
Improveservice protection capabilityVSAvoidconstruction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The backup link is designed to serve multiple purposes: it can back up any ONU/ONT equipment in the protection group, and any failed equipment can utilize the backup link of another failed equipment. This multi-functional design eliminates the need for dedicated redundant equipment for each ONU, dramatically reducing construction costs while maintaining service protection capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple ONUs are grouped into protection groups that share common backup links. Instead of each ONU having its own dedicated backup, the patent merges the backup resources of multiple ONUs into shared links, reducing the total number of redundant components needed while ensuring service continuity for all members of the protection group.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If dedicated backup channels are provided for each ONU, then service protection is improved, but bandwidth utilization decreases due to idle resources

Engineering Contradiction:
Improveservice protectionVSAvoidbandwidth utilization
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The backup link bandwidth allocation is dynamic rather than static. When no failure occurs, the backup link carries traffic from the secondary ONU to utilize bandwidth. When a failure occurs, the bandwidth is dynamically reallocated to the failed ONU's traffic. This dynamic adjustment eliminates idle bandwidth waste while ensuring protection capability is available when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The backup link is not left idle during normal operation but continuously carries useful traffic from the secondary ONU. This ensures the backup link remains active and useful at all times, eliminating resource waste while maintaining the ability to provide protection when failures occur.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If redundant equipment is added for protection, then service security is improved, but device complexity and fault location difficulty increase

Engineering Contradiction:
Improveservice securityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements automatic fault detection and protection switching without requiring complex manual intervention or additional monitoring equipment. When a failure is detected, the system automatically switches traffic to the backup link and notifies the OLT, which then allocates bandwidth accordingly. This self-service approach reduces device complexity while maintaining high service security.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates automatic feedback mechanisms where the OLT receives notifications from ONUs about link failures and automatically adjusts bandwidth allocation. This feedback loop enables the system to respond to failures automatically without requiring complex manual fault location procedures, reducing overall system complexity while maintaining service security.

Inventive Principle:
Principle #23Feedback

4Loss of energy

If backup links are shared among protection groups, then bandwidth utilization is improved, but fault diagnosis capability deteriorates

Engineering Contradiction:
Improvebandwidth utilizationVSAvoidfault location capability
Core Design Contradiction:
Loss of energyVSDifficulty of detecting and measuring

Solution Approach 1:

The OLT acts as an intermediary that receives failure notifications from ONUs and manages the backup link allocation. When an ONU detects a link failure, it notifies the OLT, which then coordinates the bandwidth reallocation and protects the service. This intermediary management simplifies fault diagnosis by centralizing the control logic at the OLT rather than requiring complex distributed diagnosis across multiple shared backup links.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP1835641B1Passive optical network system and method for protecting the services of the same
Publication Date: 2012.02.22 HUAWEI TECH CO LTD
  • EP1835641B1 patent drawingFigure 1~2
  • EP1835641B1 patent drawingFigure 3~4
  • EP1835641B1 patent drawingFigure 5~6

AI summary

The present disclosure provides a passive optical network (PON) system and a method for protecting the service of the system for service recovery and fault locating in case of a failure of the network, wherein the PON system comprises an optical line terminal (OLT), an optical distribution network (ODN) and an optical network terminal (ONT) equipment protection group comprising a plurality of ONT equipment groups, each of which is connected to at least one of other ONT equipment groups within the ONT equipment protection group for the mutual protection relationship. The PON system of the present disclosure does not require equipment and link redundancy for backup, contributes to reduced cost and improved utilization of resources, and provides a means for diagnosing any faults of the links and equipment in the network.