Three Fiber Line Switched Ring Multi-Failure Protection
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Solution Overview
Problem
Current optical shared protection rings, such as two-fiber and four-fiber BLSRs, face limitations in handling multiple failures without causing ring segmentation and protecting extra traffic, particularly in two-fiber BLSRs where more than one failure leads to ring segmentation and potential traffic loss.
Innovation Solution
A three-fiber line switched ring (3FLSR) protocol that adds a third fiber for unidirectional or bidirectional switching, enabling protection of multiple failures without ring segmentation and supporting extra traffic protection in two-fiber BLSR scenarios, while reducing costs compared to four-fiber BLSRs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-fiber BLSR is used for protection, then cost is reduced and bandwidth usage is efficient, but the system cannot protect against more than one failure without causing ring segmentation
Solution Approach 1:
The patent transitions from a two-fiber bidirectional configuration to a three-fiber unidirectional configuration, adding a dimensional change in the fiber topology. This allows the system to protect against multiple failures by utilizing the third fiber as a dedicated protection path, eliminating ring segmentation issues while maintaining cost efficiency compared to four-fiber solutions.
Solution Approach 2:
The patent segments the protection function by dedicating specific fibers to specific purposes: two fibers for working traffic and one fiber for protection traffic. This segmentation allows independent optimization of each function, enabling multi-failure protection without requiring all fibers to carry both working and protection traffic simultaneously.
2Reliability
If a four-fiber BLSR is used for protection, then multiple failures can be protected without ring segmentation, but cost increases and bandwidth usage efficiency decreases
Solution Approach 1:
The patent extracts the protection function from the working traffic carriers by dedicating a separate third fiber solely for protection purposes. This extraction allows the system to achieve four-fiber BLSR-level protection capability without requiring four fibers, as the protection function is isolated to a single dedicated fiber rather than being shared across multiple fibers.
Solution Approach 2:
The three-fiber configuration provides universal protection capability that can handle various failure scenarios (single fiber failure, multiple fiber failures, bidirectional failures) that previously required different configurations. The unidirectional third fiber serves as a universal protection path for all working traffic, replacing the need for multiple dedicated protection paths.
3Reliability
If ring switching is implemented in a two-fiber BLSR, then protection is provided, but extra traffic cannot be protected on single failure
Solution Approach 1:
The patent establishes preliminary protection paths on the third fiber before failures occur, allowing extra traffic to be pre-configured and protected. The unidirectional third fiber is prepared in advance as a dedicated protection channel, enabling the system to protect both primary and extra traffic without requiring dynamic reconfiguration during failure events.
Data Source
AI summary
A 3 fiber line switched ring (3FLSR) provides protection for (optical) transmission networking wherein N nodes are connected via 3 lines (or optical fibers) in a ring topology. Two of the three fibers form a main transmission line and may transmit in one direction in the ring whereas the third might transmit in the opposite direction. This architecture of the 3FLSR provides a dual protection scheme, including a bi-directional line switching coupled with a unidirectional line switching. Traffic is categorized based on the level of protection available for the particular traffic type. The first two transmitting fibers form a bi-directional ring, carrying primary and secondary traffic which can survive 2 and 1 failures on the ring respectively. The third fiber may form a unidirectional ring, carrying additional traffic that can be pre-empted in case of multiple failures in the bi-directional ring. The 3FLSR enables reconfiguration of existing 2/4 fiber rings and conforms to applicable standards.