SONET Ring Circuit Rerouting With Hitless Migration

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Solution Overview

Problem

SONET ring network engineering faces challenges in hitless rerouting of circuits without service disruption, particularly due to the complexity of route design and path migration, especially in larger rings, where existing solutions do not adequately account for the alignment property and often result in service disruptions.

Innovation Solution

A system and method that include a route design subsystem to identify alternative routes subject to alignment constraints and increase the objective value of the ring, along with a path migration subsystem to determine a hitless migration sequence, enabling efficient rerouting of circuits on SONET or similar rings without disrupting service.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional rerouting methods are used on operational SONET rings, then service continuity is maintained, but network optimization and bandwidth utilization cannot be improved

Engineering Contradiction:

Improvenetwork utilizationVSAvoidservice continuity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary routing calculations and identifies optimal paths before actual traffic migration is needed. The route design subsystem pre-computes alternative routes and the path migration subsystem prepares migration sequences in advance, allowing network optimization to be executed without disrupting live traffic by using bridge-and-roll functionality.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If network engineering is performed to optimize circuit layout, then bandwidth utilization improves, but service disruption occurs without hitless migration

Engineering Contradiction:

Improvebandwidth utilizationVSAvoidservice disruption

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The bridge-and-roll functionality acts as an intermediary mechanism that enables seamless transition between old and new circuit routes. The system bridges traffic to the new route and then rolls over completely, using the intermediary bridge-and-roll capability to eliminate service disruption during network engineering operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If alignment constraints are not considered in route design, then routing flexibility increases, but SONET protocol compliance is violated

Engineering Contradiction:

Improverouting flexibilityVSAvoidprotocol compliance

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The route design subsystem applies alignment constraints locally at each routing decision point while maintaining global routing flexibility. By considering alignment requirements at specific locations in the network topology, the system ensures SONET protocol compliance without sacrificing overall routing adaptability.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7864690B2System and method for rerouting circuits on SONET and SDH rings without disrupting service

Publication Date: 2011.01.04 NOKIA OF AMERICA CORP

AI summary

A system and method for rerouting circuits on a SONET, SDH or similar ring without disrupting service. In one embodiment, the system includes: (1) a route design subsystem adapted to identify, for the circuits, alternative routes that are subject to an alignment constraint and increase an objective value associated with the ring and (2) a path migration subsystem, associated with the route design subsystem, adapted to determine a hitless migration sequence that allows the alternative routes to be employed.