Wireless Mesh Backhaul Resilience via Proxy Controller and Local Switching

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Solution Overview

Problem

Wireless mesh networks face disruptions when connectivity between access points and controllers is lost, leading to improper routing of data traffic, and challenges in synchronizing WLAN/VLAN mappings and managing IP subnet roaming, which affects network stability and efficiency.

Innovation Solution

Implementing resilient backhaul links, proxy controller functionality, and synchronized WLAN/VLAN mapping propagation across the network, along with adaptive IP subnet management techniques to maintain connectivity and update mappings during AP roaming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the mesh network uses a controller for central control of data traffic routing, then data traffic routing is improved, but network reliability deteriorates when connectivity between APs and controller is lost

Engineering Contradiction:

Improvedata traffic routing efficiencyVSAvoidnetwork stability during controller unavailability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements self-service by enabling root APs to autonomously assume proxy controller functionality when the central controller becomes unavailable. The root AP detects controller unavailability and automatically takes over traffic routing responsibilities without external intervention, allowing the mesh network to continue operating independently

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent prepares for controller failures by pre-configuring root APs with proxy controller capabilities and maintaining resilient backhaul links. This beforehand cushioning ensures that when controller connectivity is lost, the network can immediately transition to alternative routing paths through root APs without complete network dissolution

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the mesh network implements resilient backhaul links with proxy controller functionality, then network reliability is improved, but device complexity increases

Engineering Contradiction:

Improvenetwork stability during controller outagesVSAvoidAP functionality and control mechanisms

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by enabling root APs to perform multiple roles: normal traffic routing, proxy controller functionality, and resilient backhaul maintenance. This universal capability allows a single component (root AP) to handle multiple functions depending on system state, reducing the need for separate dedicated controller hardware

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If the mesh network synchronizes WLAN/VLAN mappings continuously, then routing accuracy is improved, but network overhead increases

Engineering Contradiction:

ImproveWLAN/VLAN mapping accuracyVSAvoidnetwork bandwidth consumption for mapping synchronization

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent implements periodic action by establishing initial WLAN/VLAN mappings during AP bootstrap phase and then updating them periodically or on-change rather than continuously. This approach maintains mapping accuracy while reducing unnecessary synchronization traffic during stable network conditions

Inventive Principle:

Principle #19Periodic action

4Adaptability or versatility

If the mesh network supports AP roaming across different IP subnets, then network adaptability is improved, but routing stability deteriorates

Engineering Contradiction:

ImproveAP mobility across IP subnetsVSAvoidrouting stability during AP roaming

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies feedback mechanisms by having APs continuously report their location and IP subnet information to the controller and to neighboring APs. This feedback enables dynamic routing updates and mesh topology adjustments that maintain routing stability even as APs roam between different IP subnets

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10225180B2Wireless mesh network including resilient backhaul links and WLAN traffic local switching

Publication Date: 2019.03.05 CISCO TECHNOLOGY INC

AI summary

A method is performed at a mesh access point (MAP) in a wireless mesh network including access points (APs) of a spanning tree being divided among multiple Internet Protocol (IP) subnets. The method includes receiving from a first parent AP to which the MAP is a child a first IP subnet identifier indicating the first IP subnet to which the first parent AP belongs. The method also includes obtaining a first IP address associated with the first IP subnet, roaming from the first to a second parent AP, receiving from the second parent AP a second IP subnet identifier indicating a second IP subnet to which the second parent AP belongs, determining if the first and second parent APs are both part of the same IP subnet, and determining whether to maintain connectivity with a current controller or establish connectivity to a new controller based on results of the determining.