EVPN Peer Backup Path Computation for Link Failure Recovery

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In network devices implementing Ethernet Virtual Private Networks (EVPN), existing configurations face disruptions due to link failures in single-active multihoming setups, where only one active EVPN peer device forwards traffic, and the standby device does not, leading to potential traffic drops during link failures.

Innovation Solution

EVPN peer devices compute and store backup paths based on backup MAC and IP advertisements from standby devices, allowing seamless traffic rerouting when a link failure occurs, promoting the standby device to active status to maintain network connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-active multihoming configuration is used where only one active EVPN peer device forwards traffic, then device complexity is reduced and ease of operation is improved, but reliability deteriorates due to traffic drops during link failures

Engineering Contradiction:

Improvenetwork connectivity reliabilityVSAvoidEVPN configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the active EVPN peer device compute and store a backup best path in advance, before any link failure occurs. The backup path is calculated based on a backup MAC and IP advertisement route advertised by the standby peer device, ensuring that when a link failure occurs, the device can immediately switch to the pre-computed backup path without delay, thus maintaining reliability while keeping the configuration relatively simple

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the standby EVPN peer device does not forward traffic in single-active configuration, then ease of operation is improved and device complexity is reduced, but productivity deteriorates due to traffic disruption during failures

Engineering Contradiction:

Improvetraffic forwarding continuityVSAvoidconfiguration simplicity

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent applies self-service by enabling the active EVPN peer device to automatically compute, store, and utilize its own backup path when a link failure occurs. The device monitors its own link status and autonomously switches to the backup path without requiring manual intervention or complex configuration changes, thereby maintaining productivity while preserving configuration simplicity

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements feedback mechanisms where the active EVPN peer device monitors link status and receives backup MAC and IP advertisement routes from the standby peer device. This feedback loop enables the active device to detect link failures and automatically switch to the backup path, ensuring traffic forwarding continuity while maintaining relatively simple operation

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12015544B1Backup route for network devices in multihoming configuration

Publication Date: 2024.06.18 ARISTA NETWORKS INC

AI summary

First and second network devices may be configured to multihome a host. The first network device may advertise a first MAC and IP advertisement route indicative of a first link between the first network device and the host. The second network device may advertise a backup MAC and IP advertisement route indicative of a second link between the second network device and the host. Based on the backup MAC and IP advertisement route, the first network device may store a backup path for reaching the host via the second network device. After failure of the first link, the first network device may forward traffic destined for the host based on the stored backup path.