Compressed Segment Routing Path Protection via Monitoring Stack

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Solution Overview

Problem

Existing network traffic engineering systems face challenges in routing traffic efficiently using compressed segment routing label stacks, as they may deviate from intended paths due to network changes, leading to potential congestion and violation of traffic constraints, especially when using prefix segment identifiers that do not guarantee strict route assignment.

Innovation Solution

Implementing a system with a monitoring label stack that includes adjacency segment identifiers for path validation and a forwarding label stack that uses compressed segment identifiers, including prefix identifiers, to ensure traffic follows the intended path while maintaining an alternate path for rerouting in case of failures or network changes, thereby preventing automatic rerouting by interior gateway protocols that could violate traffic constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If compressed segment routing label stacks with prefix segment identifiers are used, then network routing flexibility and scalability are improved, but path validation capability deteriorates because prefix identifiers do not guarantee strict route assignment

Engineering Contradiction:
Improverouting flexibilityVSAvoidpath validation capability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the label stack into two distinct parts: a compressed segment routing label stack for routing flexibility and a monitoring label stack with adjacency segment identifiers for path validation. This segmentation allows each part to serve its specific function without compromising the other, resolving the contradiction between routing flexibility and path validation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The monitoring label stack acts as an intermediary between the compressed segment routing label stack and the network forwarding plane. It provides the necessary path validation information that the compressed label stack lacks, enabling strict route assignment while maintaining routing flexibility through the compressed stack.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If monitoring label stack with adjacency segment identifiers is maintained, then path validation capability is improved, but device complexity increases due to maintaining two separate label stacks

Engineering Contradiction:
Improvepath validation capabilityVSAvoidlabel stack management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller performs multiple functions using the two label stacks: the compressed segment routing label stack handles routing flexibility and scalability, while the monitoring label stack handles path validation. This multi-functionality approach consolidates diverse requirements into a unified system architecture, managing complexity through clear functional separation rather than increasing it.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If prefix segment identifiers are used in compressed label stack, then network scalability is improved, but traffic constraint compliance deteriorates due to lack of strict route assignment

Engineering Contradiction:
Improvenetwork scalabilityVSAvoidtraffic constraint compliance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the routing information into compressed prefix segment identifiers for scalability and adjacency segment identifiers in the monitoring stack for traffic constraint compliance. This segmentation allows the system to simultaneously achieve network scalability through prefix identifiers and strict route assignment through adjacency identifiers, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3619896B1Mechanism and apparatus for path protection when using compressed segment routing label stacks
Publication Date: 2021.08.04 GOOGLE LLC
  • EP3619896B1 patent drawingFigure 1
  • EP3619896B1 patent drawingFigure 2A
  • EP3619896B1 patent drawingFigure 2B

AI summary

Systems and methods of network traffic engineering are provided. The system includes a switch and a controller. The controller can maintain a monitoring segment identifier set defining a path for traffic intended for a destination device. The controller can maintain a forwarding segment identifier set representing a compressed version of the monitoring segment identifier set such that traffic, when labeled according to the forwarding segment identifier set, will follow the path defined by the monitoring segment identifier set. The controller can monitor a status of the path defined by the monitoring segment identifier set. The controller can, subject to determining that the path defined by the monitoring segment identifier set is invalid, cause the switch to not label a packet received at the switch according to the forwarding segment identifier set.