GPON OLT Traffic Rerouting via Standard Routing Protocols

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Solution Overview

Problem

Resilient optical communications networks face challenges in efficiently routing traffic during failures, particularly in centralized node architectures, where existing solutions require additional hardware, functionality, or increased costs, and lack standardized mechanisms for higher network level switching.

Innovation Solution

A communications network architecture with dual-homed optical line terminals and edge routers, utilizing standard protocols and existing equipment, where a standby network connection is activated and metric values are adjusted to reroute traffic upon failure, without requiring additional customer premises equipment functionality or hardware, leveraging GPON OAM and standard routing protocols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Ethernet OAM functionality is implemented in each individual CPE to enable connectivity status checking, then network resilience is improved, but the cost of CPE devices increases

Engineering Contradiction:
Improvenetwork resilienceVSAvoidCPE device cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediary mechanism where the OLT (Optical Line Terminal) performs the connectivity status checking function instead of requiring each CPE to have Ethernet OAM functionality. The OLT acts as a central coordinator that manages the dual-homed PON system, exchanging status packets with edge routers to detect failures and trigger protection switching, thereby eliminating the need for expensive OAM functionality in every CPE device

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system enables self-service through automated failure detection and protection switching mechanisms. The OLT autonomously monitors network status by exchanging packets with edge routers, automatically detects failures when connectivity is lost, and triggers the protection switching process without requiring manual intervention or complex OAM functionality in CPE devices

Inventive Principle:
Principle #25Self-service

2Reliability

If additional external FROTH routers or additional functionality in existing routers is required to support fault detection, then network resilience is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidrouter functionality
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the existing OLT perform multiple functions: it acts as both the PON management system and the fault detection mechanism. The OLT uses standard routing protocol packets (already present in the network infrastructure) to exchange connectivity status information with edge routers, eliminating the need for specialized FROTH routers or additional router functionality while maintaining comprehensive fault detection capability

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

3Reliability

If dynamic IP routing protocols are run between the communications provider's network and CPE to detect connectivity loss, then network resilience is improved, but stability decreases

Engineering Contradiction:
Improveconnectivity loss detectionVSAvoidnetwork stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent implements preliminary action by pre-configuring dual network paths (active and standby) and pre-establishing the protection switching mechanism before failures occur. The OLT continuously monitors the active path using standard routing protocol packets and can immediately switch to the pre-configured standby path when a failure is detected, avoiding the instability of dynamic routing protocols while maintaining rapid failure detection and recovery

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2622872B1Communications network
Publication Date: 2014.10.08 BRITISH TELECOM PLC
  • EP2622872B1 patent drawingFigure 1
  • EP2622872B1 patent drawingFigure 2
  • EP2622872B1 patent drawingFigure 3

AI summary

A passive optical network is provided which uses existing GPON OAM functionality and standard routing protocol messages to solve the downstream routing problem between an access service provider and one or more other communication provider networks.