BGP Aggregate Exception Path Attribute for Routing Reliability

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Solution Overview

Problem

BGP route summarization can cause traffic blackholing and sub-optimal routing during network failures, forcing administrators to disable route aggregation, which compromises scalability and network performance.

Innovation Solution

Introduction of a new BGP path attribute called 'Aggregate Exception' that allows for the identification and advertisement of network failures and recoveries, enabling dynamic updates and alternative path routing without losing the benefits of route aggregation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If BGP route aggregation is used, then network scalability and performance are improved, but traffic blackholing and sub-optimal routing occur during network failures

Engineering Contradiction:

Improvenetwork scalabilityVSAvoidrouting reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the aggregated route information by introducing a new BGP path attribute called 'Aggregate Exception' that carries individual prefix information within the aggregated route advertisement. This allows the system to maintain route aggregation for scalability while providing granular control over individual prefixes, enabling selective path selection during failures without requiring full route unaggregation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the BGP path attribute parameters by adding the 'Aggregate Exception' attribute that includes a list of prefixes and their corresponding next-hop information. This parameter enhancement allows the system to convey both aggregated route information and specific prefix exceptions simultaneously, resolving the contradiction between aggregation benefits and failure handling capabilities.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If BGP route aggregation is removed to handle failures, then routing reliability is improved, but network scalability and performance deteriorate

Engineering Contradiction:

Improverouting reliabilityVSAvoidnetwork scalability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments the routing information by introducing the 'Aggregate Exception' BGP path attribute that carries individual prefix information within the aggregated route advertisement. This allows the system to maintain route aggregation for scalability while providing granular control over individual prefixes, enabling selective path selection during failures without requiring full route unaggregation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic path selection by allowing BGP speakers to automatically switch between aggregated routes and specific prefix exceptions based on real-time network conditions. The 'Aggregate Exception' attribute enables dynamic withdrawal or modification of specific prefixes while maintaining the overall aggregated route structure, providing adaptive reliability without sacrificing scalability.

Inventive Principle:

Principle #15Dynamics

3Quantity of substance

If route summarization is used, then the number of routes in the data plane is reduced, but traffic blackholing occurs during network failures

Engineering Contradiction:

Improvenumber of routesVSAvoidtraffic delivery

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The 'Aggregate Exception' BGP path attribute acts as an intermediary that bridges the gap between aggregated route advertisements and individual prefix information. It carries embedded prefix lists and next-hop information within the aggregated route structure, allowing receiving BGP speakers to identify specific failed prefixes and select alternative paths without requiring complete route unaggregation.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Quantity of substance

If route aggregation is maintained, then hardware forwarding chip resources are conserved, but BGP convergence timing increases during failures

Engineering Contradiction:

Improvehardware resourcesVSAvoidconvergence time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by pre-calculating and embedding alternative next-hop information within the 'Aggregate Exception' attribute during normal operation. When failures occur, BGP speakers can immediately switch to the pre-prepared alternative paths contained in the exception attribute, significantly reducing convergence time without requiring full route unaggregation or extensive real-time computation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11750497B2BGP route aggregation exception systems and methods

Publication Date: 2023.09.05 CIENA CORP

AI summary

Systems and methods for a Border Gateway Protocol (BGP) route aggregation exception include advertising, to BGP peers, of a plurality of prefixes using BGP route aggregation or summarization; detecting a failure that is local to the router affecting a prefix of the plurality of prefixes; and advertising an aggregation exception that identifies the prefix to all of the BGP peers. The systems and methods can also include detecting recovery of the failure; and sending a withdrawal of the aggregation exception to all of the BGP peers.