OTN Ring Network Protection via Extended APS/PCC Overhead Bytes

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Solution Overview

Problem

The existing ring network protection technologies for Optical Transport Networks (OTN) face challenges similar to those in Synchronous Digital Hierarchy (SDH) networks, including inefficient protection switching and potential overhead byte loss, which hinder effective protection switching in OTN networks.

Innovation Solution

The method extends the G.841 protocol by setting additional fields in the overhead byte APS/PCC of ODUk, including a serial number field, check field, switch page field, and modifying existing fields to enhance protection switching, error detection, and protocol management, ensuring reliable protection switching and recovery in OTN ring networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the G.841 protocol is used for protection switching in OTN ring networks, then the basic protection switching function is provided, but overhead byte loss occurs and protection switching reliability is insufficient

Engineering Contradiction:
Improveprotection switching reliabilityVSAvoidoverhead byte loss
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent introduces a serial number field in the overhead byte to record the sequence number of each overhead byte. Before protection switching occurs, the expected serial number is established. During protection switching, the actual serial number is compared with the expected serial number to detect missing or lost overhead bytes in advance, preventing unreliable switching without requiring complex post-error correction mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where network elements transmit the serial number of overhead bytes in the APS/PCC field. Receiving network elements use this feedback information to verify the完整性 of received overhead bytes by comparing serial numbers. This feedback loop enables real-time detection and prevention of overhead byte loss, significantly improving protection switching reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If additional fields are added to the overhead byte APS/PCC to enhance protection switching, then protection switching reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveprotection switching reliabilityVSAvoidoverhead byte structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies existing overhead byte parameters by introducing a serial number field and check field within the APS/PCC structure. Instead of adding entirely new overhead bytes or complex processing mechanisms, the solution changes the parameter structure of existing fields to include verification capabilities. This approach enhances reliability while minimizing the increase in device complexity by utilizing and extending existing overhead byte space rather than creating new structural layers.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1890406B1A method for protecting the ring network of optical transport network
Publication Date: 2012.12.26 HUAWEI TECH CO LTD
  • EP1890406B1 patent drawingFigure 1~2
  • EP1890406B1 patent drawingFigure 3~4
  • EP1890406B1 patent drawingFigure 5

AI summary

A method for protecting the ring network of optical transport network, it utilizes the overhead bytes APS/PCC in the ODUk to transmit the auto protective inversion information, the method adds some fields in the APS/PCC, including steps of: a. the node in OTN, in which the protective inversion occurs, transmits the protective inversion information to other nodes through the field set in the APS/PCC of ODUk; b. The node, which receives the ODUk, performs the corresponding process according to the field in the APS/PCC in the ODUk, and realizes protective inversion to the OTN ring network. The present invention transmits the auto protective inversion information by extending the overhead byte APS/PCC, the node in the OTN ring network performs the corresponding process according to the field in the overhead byte, therefore it realizes the protective inversion to the OTN ring network, and protects the ONT ring network from occurring problems as those occurred in the SDH ring network.