FlexO/ZR Subrating for Partial Carrier Failure Survivability
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Solution Overview
Problem
Existing optical networking systems lack partial survivability at the FlexO/ZR interface layer, leading to significant network disruptions and increased bandwidth requirements when a single carrier or module fails, especially in high-speed interfaces like 400G and 800G, as the entire interface is considered down despite only a portion being affected.
Innovation Solution
Implementing partial survivability methods through partial Alarm Indication Signal (P-AIS), partial Backward Defect Indication (P-BDI), and partial Server Signal Fail (P-SSF) signals to selectively manage failures at the FlexO/ZR interface, allowing affected services to be moved or resized on non-failed carriers, and adjusting overhead to maintain network integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire optical interface is considered down when a single carrier fails, then network reliability is maintained through complete failure isolation, but service continuity and network stability deteriorate due to unnecessary complete interface shutdowns
Solution Approach 1:
The patent segments the optical interface into multiple independent carriers (e.g., four 100G carriers for a 400G interface). When one carrier fails, only that specific carrier is taken down while the other carriers continue to operate. This segmentation allows partial survivability where services can be maintained on remaining carriers rather than shutting down the entire interface.
2Device complexity
If the entire interface is restored when a single carrier fails, then network simplicity is maintained, but bandwidth consumption and restoration cost increase significantly
Solution Approach 1:
The patent applies local quality by treating each carrier independently for failure detection and restoration purposes. Restoration actions are applied locally to only the failed carrier rather than the entire interface. This allows the network to restore only the affected 100G carrier capacity rather than restoring the full 400G interface, significantly reducing restoration bandwidth consumption.
3Productivity
If partial survivability is implemented at FlexO/ZR interface layer, then service continuity and bandwidth efficiency improve, but interface complexity and control complexity increase
Solution Approach 1:
The patent implements dynamics by enabling the interface to operate in different modes: full rate operation when all carriers are functional, and subrate operation when one or more carriers fail. The interface dynamically adjusts its operational state based on carrier availability, transitioning between 400G full rate and lower subrates (e.g., 300G, 200G, 100G) depending on how many carriers are operational.
4Stability of the object's composition
If subrating is implemented to maintain unaffected services, then service continuity and network stability improve, but interface rate reduction and capacity loss occur
Solution Approach 1:
The patent applies partial action by implementing subrating that maintains only the necessary capacity for affected services. When one carrier fails in a 400G interface, the system reduces rate to a level that is sufficient for the remaining operational carriers and their services, rather than maintaining full 400G rate unnecessarily. This partial rate reduction optimizes bandwidth efficiency while maintaining service continuity.
Data Source
AI summary
An optical interface includes circuitry configured to operate the optical interface at a first rate, subsequent to a requirement to subrate the optical interface to a second rate, determine which services are affected, signal a partial failure for the one or more affected services, and operate the optical interface at a second rate that is less than the first rate. The optical interface can be a Flexible Optical (FlexO) or ZR interface.