PON OLT Subscriber Line Terminal State Synchronization

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Solution Overview

Problem

Existing methods for updating firmware in Optical Line Terminals (OLTs) in PON systems often require halting communication, leading to disruptions in services like VoIP and video distribution, and result in mismatches between the management states of upper and lower processing units during the update process.

Innovation Solution

A subscriber line terminal with an upper layer processing unit and a lower layer processing unit, along with a matching unit, allows for seamless state synchronization after a reboot by accumulating and notifying events during the halt period, ensuring continuous communication and preventing state mismatches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If firmware update is performed by halting the upper processing unit, then firmware can be updated, but communication service is disrupted

Engineering Contradiction:

Improvefirmware update capabilityVSAvoidcommunication service continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The OLT is divided into two independent processing units: upper processing unit (handles management and control) and lower processing unit (handles communication protocols). This segmentation allows the upper unit to be halted for firmware updates while the lower unit continues communication operations, resolving the contradiction between update capability and service continuity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lower processing unit acts as an intermediary that maintains communication services during upper unit halts. It receives and processes communication frames independently, ensuring service continuity while the upper unit undergoes firmware updates.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If upper processing unit is halted during firmware update, then update can be performed, but state mismatch occurs between processing units

Engineering Contradiction:

Improvefirmware update capabilityVSAvoidstate synchronization

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

Before the upper processing unit is halted for firmware update, its current operational state is saved and stored. After the update completes, the saved state is restored, ensuring state synchronization between the upper and lower processing units without information loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements state feedback mechanisms where the lower processing unit's state is continuously monitored and compared with the restored upper unit state. This feedback ensures state consistency and detects any mismatches that may occur during the update process.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9232282B2Subscriber line terminal, control method, and control method for PON system

Publication Date: 2016.01.05 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

There is provided a technique that enables a process to be performed smoothly between two processing units of an OLT after rebooting of one of the processing units even in the case where a process by the processing unit is temporarily halted. An upper processing unit can be temporarily halted when updating firmware. A basic communication unit (lower processing unit) is configured to maintain its operation even when the upper processing unit is temporarily halted. When an event occurs during a halt period of the upper processing unit, a matching unit matches a management state stored in a first storage unit with a management state stored in a second storage unit after the halt period of the upper processing unit.