Wireless Switch Load Balancing for Layer 3 Roaming

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Solution Overview

Problem

Current WLAN technologies face challenges in maintaining seamless IP connectivity and load balancing across different IP subnets during layer 3 roaming, leading to disruptions in applications like VoIP and streaming, and result in sub-optimal routing and increased latency.

Innovation Solution

Implementing a registration server that creates a mesh network of wireless switches, allowing clients to maintain their original IP address by tunneling traffic through a new home wireless switch selected based on load balancing criteria, and using DHCP to manage IP address assignments dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If a client roams to a new access point in a different IP subnet, then the client can extend its wireless coverage area, but IP connectivity is disrupted and the client must obtain a new IP address

Engineering Contradiction:
Improvewireless coverage areaVSAvoidIP connectivity
Core Design Contradiction:
Area of moving objectVSReliability

Solution Approach 1:

The patent introduces a home wireless switch as an intermediary that maintains the client's original IP address and tunnels traffic between the client's new location (foreign wireless switch) and the original subnet. This mediator enables seamless layer 3 roaming by preserving the IP address while allowing physical movement across subnets.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the network into home wireless switches and foreign wireless switches, where the home wireless switch maintains the client's IP address and the foreign wireless switch provides local connectivity. This segmentation allows independent optimization of each component while maintaining overall IP connectivity.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If multiple clients are assigned to a single home wireless switch, then IP address management is simplified, but the wireless switch experiences increased load and performance degradation

Engineering Contradiction:
ImproveIP address management complexityVSAvoidwireless switch performance
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The foreign wireless switch acts as an intermediary that handles local client connections and tunnels traffic to the home wireless switch. This distributes the load by allowing foreign switches to handle local connectivity while home switches manage IP addressing, preventing any single switch from becoming a bottleneck.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adds a dimensional separation between home wireless switches (IP management function) and foreign wireless switches (connectivity function). This dimensional change allows load distribution across multiple switches while maintaining centralized IP address management.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a client maintains its original IP address while roaming to a different subnet, then application sessions remain active, but routing complexity increases and latency increases

Engineering Contradiction:
Improveapplication session continuityVSAvoidrouting latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The home wireless switch is pre-configured with the client's original IP address and subnet information before roaming occurs. This preliminary setup enables rapid tunnel establishment and minimal latency during the roaming transition, as the routing path is already determined.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous IP connectivity by establishing a tunnel that preserves the client's original IP address and routing path. This continuity ensures that application sessions remain active without interruption or increased latency, as the useful action of IP communication continues uninterrupted.

Inventive Principle:
Principle #20Continuity of useful action

4Area of moving object

If wireless switches are deployed across multiple IP subnets to increase network coverage, then geographic coverage is improved, but load balancing between switches becomes difficult and routing optimization is reduced

Engineering Contradiction:
Improvenetwork coverage areaVSAvoidload balancing capability
Core Design Contradiction:
Area of moving objectVSEase of operation

Solution Approach 1:

The patent makes wireless switches multi-functional by enabling them to operate as either home wireless switches (IP management) or foreign wireless switches (connectivity), or both simultaneously for different clients. This universality simplifies load balancing by allowing any switch to handle multiple roles and enabling dynamic assignment based on load conditions.

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

Solution Approach 2:

The patent introduces dynamic role assignment where wireless switches can transition between home and foreign roles based on real-time load conditions and client roaming patterns. This dynamic behavior enables automatic load balancing across multiple subnets without complex manual configuration.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1884089B1METHOD, SYSTEM AND APPARATUS FOR LOAD BALANCING OF WIRELESS SWITCHES TO SUPPORT LAYER 3 ROAMING IN WIRELESS LOCAL AREA NETWORKS (WLANs)
Publication Date: 2010.05.05 SYMBOL TECH INC
  • EP1884089B1 patent drawingFigure 1~2
  • EP1884089B1 patent drawingFigure 3~4
  • EP1884089B1 patent drawingFigure 5~6

AI summary

Techniques are provided for load balancing among a plurality of wireless switches configured to support a plurality of clients including a first client. An initial home wireless switch can be configured to initially support the first client. The initial home wireless switch can select one of the wireless switches as a new home wireless switch for the first client. These techniques can be implemented, for example, in a wireless local area network.