Centralized Controller for Segment Routing Inter-AS Link State
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Solution Overview
Problem
In segment routing networks, the lack of state or session information for inter-autonomous system links leads to unsuccessful traffic forwarding on non-operational links, resulting in lost traffic and wastage of computing and networking resources.
Innovation Solution
A centralized controller platform that receives BGP data, filters prefixes to identify inter-autonomous system link data, determines operational states, and performs actions such as rerouting traffic or repairing non-operational links based on this information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If segment routing is used to interconnect autonomous systems, then network simplicity and routing efficiency are improved, but state information for inter-AS links is lost leading to traffic forwarding failures
Solution Approach 1:
The patent introduces BGP as an intermediary mechanism between segment routing and inter-AS link state monitoring. BGP route updates serve as mediators to convey link state information across autonomous system boundaries, allowing the segment routing infrastructure to maintain simplicity while reliably detecting link failures through BGP prefix withdrawal events.
Solution Approach 2:
The patent segments the monitoring function by separating link state detection (performed via BGP at boundary routers) from traffic forwarding decisions (performed by segment routing internally). This segmentation allows each component to operate independently with appropriate mechanisms, resolving the contradiction between simplicity and reliability.
2Reliability
If inter-AS link state monitoring is implemented, then traffic forwarding reliability is improved, but computing and networking resources are consumed
Solution Approach 1:
The patent implements self-service monitoring where BGP speakers naturally generate and propagate link state information through their existing route update mechanisms. No separate monitoring infrastructure or additional processing resources are required, as the BGP protocol itself provides the monitoring function as a byproduct of its routing information exchange.
Solution Approach 2:
The patent makes BGP serve multiple functions: traditional inter-AS routing and simultaneous link state monitoring. By utilizing BGP's existing update mechanisms for both purposes, the system avoids duplicating functionality and reduces overall resource consumption while maintaining reliable link state awareness.
3Measurement precision
If BGP data filtering is performed to identify inter-AS link state, then link state detection accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary filtering rules to BGP update messages as they arrive, immediately identifying those relevant to inter-AS link state before further processing. By pre-filtering based on established criteria (such as prefix withdrawal patterns), the system achieves accurate detection without requiring exhaustive analysis of all BGP data, thus minimizing processing time while maintaining precision.
Data Source
AI summary
A device receives border gateway protocol (BGP) data associated with links provided in a segment routing network. The segment routing network includes a first autonomous system (AS) with first network devices interconnected by a first portion of the links, a second AS with second network devices interconnected by a second portion of the links, and an inter-AS link provided between one of the first network devices and one of the second network devices. The device filters prefixes of the BGP data to identify BGP data associated with the inter-AS link, where the BGP data associated with the inter-AS link includes data identifying state information associated with the inter-AS link. The device determines an operational state of the inter-AS link based on the BGP data associated with the inter-AS link, and performs one or more actions based on the operational state of the inter-AS link.