Selective EVPN Route Refresh to Reduce BGP CPU Load

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Solution Overview

Problem

Existing Ethernet Virtual Private Network (EVPN) systems face inefficiencies in route refresh mechanisms, leading to unnecessary CPU usage and network churn due to the advertisement of complete BGP routing information bases, even when only selective route types are required.

Innovation Solution

A new route refresh mechanism is introduced that allows Border Gateway Protocol (BGP) nodes to negotiate and advertise selective EVPN routes based on specific route types, using a new route refresh message with designated route type information, reducing unnecessary route updates and CPU usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complete BGP routing information base is advertised during route refresh, then all route types are ensured to be updated, but unnecessary CPU usage and network churn increase

Engineering Contradiction:

Improveroute update completenessVSAvoidCPU usage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts only the necessary subset of route types from the complete BGP routing information base during route refresh operations. By identifying and advertising only the specific route types that are currently needed rather than all available routes, the system reduces CPU processing overhead and minimizes unnecessary network traffic while maintaining updates for required route types.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the BGP routing information base into distinct route type categories and enables selective advertisement of individual segments. This segmentation allows the system to refresh only specific portions of the routing table (e.g., only L2VPN routes or only L3VPN routes) based on current requirements, rather than forcing a complete refresh of all route types simultaneously.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a complete BGP routing information base is advertised during route refresh, then all route types are ensured to be updated, but network traffic increases

Engineering Contradiction:

Improveroute update completenessVSAvoidnetwork traffic

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and transmits only the necessary subset of route types from the complete BGP routing information base. By filtering out route types that are not currently required and advertising only the essential ones, the system significantly reduces the volume of routing update traffic across the network while ensuring that all necessary route information is still propagated.

Inventive Principle:

Principle #2Taking out (Extraction)

3Loss of energy

If selective route types are advertised, then CPU usage and network traffic are reduced, but route update completeness may be compromised

Engineering Contradiction:

ImproveCPU usageVSAvoidroute update completeness

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent implements dynamic selection of route types for advertisement based on current network requirements and peer capabilities. The system adaptively determines which route types need to be refreshed at any given moment, allowing flexible adjustment between selective and complete advertisement modes depending on the specific operational context, thereby maintaining reliability while optimizing resource usage.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback mechanisms where BGP peers exchange information about their route type requirements and capabilities. This feedback loop enables each peer to understand what route types the other needs, allowing intelligent selective advertisement that ensures completeness of necessary updates while avoiding transmission of unnecessary route types.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If a new route refresh message with route type indication is implemented, then selective route advertisement is enabled, but message complexity increases

Engineering Contradiction:

Improveroute selection flexibilityVSAvoidmessage structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent nests the route type indication information within the existing BGP route refresh message structure. By embedding the subset of route types specification inside the standard BGP message format rather than creating a completely new message type, the system adds functionality while minimizing structural complexity and maintaining compatibility with existing BGP processing frameworks.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS12452159B2Advertisement of selective EVPN routes based on route types

Publication Date: 2025.10.21 CIENA CORP

AI summary

A router is configured to send an advertisement of selective Ethernet Virtual Private Network (VPN) (EVPN) routes based on the Route Types. The router is configured to determine a requirement for a route refresh from a Border Gateway Protocol (BGP) peer for a subset of Route Types of all of the Route Types, send a route refresh message to the BGP peer with an indication of the subset of Route Types, and receive updated routes from the BGP peer only for the subset of Route Types. The indication can be included in a reserved field and payload of the route refresh message. The route refresh message can be defined in RFC 2918.