Segment Routing Flex Algo Extended Protection Across Sub-Networks
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Solution Overview
Problem
Segment Routing Flexible Algorithm (Flex Algo) segregates networks into small, segregated networks, leading to decreased fault tolerance due to non-availability or suboptimal protection paths for one or more hops, as Topology Independent Loop-Free Alternate (TI-LFA) protection is limited to the Flex Algo sub-network domain.
Innovation Solution
Implement a new Flexible Algorithm Definition (FAD) with extended protection information, using a new sub-Type, Length, Value (TLV) to advertise and configure additional Flex Algos for protection, allowing nodes to switch traffic when faults occur and recover to the original Flex Algo upon fault recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Flex Algo segregates network into small sub-networks for traffic optimization, then traffic routing flexibility is improved, but fault tolerance deteriorates due to limited protection paths
Solution Approach 1:
The patent merges multiple Flex Algo sub-networks by establishing protection relationships between them. When a primary Flex Algo experiences a fault, the system combines resources from a secondary Flex Algo to provide alternative paths, thereby maintaining fault tolerance while preserving the segmentation benefits for traffic optimization.
Solution Approach 2:
The patent introduces an extended protection mechanism that acts as an intermediary between segregated Flex Algo sub-networks. This intermediary layer enables cross-sub-network protection paths without requiring full network segmentation, allowing traffic to bypass faults by routing through the intermediary protection mechanism.
2Device complexity
If TI-LFA protection is implemented per Flex Algo sub-network domain, then protection computation is simplified, but protection path availability deteriorates due to domain limitations
Solution Approach 1:
The patent segments the protection mechanism into hierarchical levels: primary protection within each Flex Algo sub-network using TI-LFA, and secondary extended protection across multiple sub-networks. This segmentation allows each segment to maintain simple TI-LFA computation while the hierarchy as a whole provides broader protection path availability.
Solution Approach 2:
The patent implements nested protection where extended protection between Flex Algo sub-networks encapsulates the inner TI-LFA protection mechanisms. When primary TI-LFA protection fails, the nested extended protection layer activates, providing backup paths without requiring complete redesign of the inner protection structure.
Data Source
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AI summary
Systems and methods for extended protection in a Segment Routing network (10, 30, 50) that utilizes Flexible Algorithm include defining (302) a first Flexible Algorithm that segregates the Segment Routing network (10, 30, 50) into a first subset network that excludes any of links and nodes from the Segment Routing network (10, 30, 50); defining (304) a second Flexible Algorithm that segregates the Segment Routing network (10, 30, 50) into a second subset network, different from the first subset network; and defining (306) extended protection for the first Flexible Algorithm with the second Flexible Algorithm whereby the second Flexible Algorithm is usable to protect one or more of a path, a node, and a link available in the first Flexible Algorithm.