Wireless Switch Network Architecture for Layer 3 Mobility Domains
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Solution Overview
Problem
Current wireless local area networks (WLANs) face challenges in maintaining IP connectivity and application-layer connectivity when wireless client devices roam across different IP subnets, as existing solutions like Mobile IP can result in sub-optimal routing and require additional software on client devices, making them unsuitable for applications like VoIP over 802.11.
Innovation Solution
Configuring wireless switches within a mobility domain to establish peering sessions using GRE-over-IP tunnels and TCP control connections, allowing wireless client devices to retain their Layer 3 addresses and maintain network connectivity while roaming, without requiring changes to client devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless client devices roam across different IP subnets using existing solutions like Mobile IP, then IP connectivity can be maintained, but sub-optimal routing occurs and additional software is required on client devices
Solution Approach 1:
The patent introduces wireless switches as intermediary devices that establish peering sessions and data tunnels between different IP subnets. These switches handle the complexity of maintaining IP connectivity and routing information, eliminating the need for additional software on client devices. The wireless switches act as mediators that transparently manage Layer 3 roaming while clients use standard protocols.
Solution Approach 2:
The system enables self-service by allowing wireless client devices to maintain their original IP addresses and roam across subnets without requiring any special software or configuration changes. The infrastructure (wireless switches) automatically handles the complexity of inter-subnet routing, and clients simply continue using standard network protocols as if roaming within the same subnet.
2Adaptability or versatility
If wireless switches establish peering sessions with all other wireless switches in the mobility domain, then seamless Layer 3 roaming is enabled, but the number of control connections and data tunnels increases
Solution Approach 1:
The patent segments the mobility domain into multiple wireless switches, each responsible for managing peering sessions with other switches. This segmentation allows the system to handle Layer 3 roaming by distributing the control connections and data tunnels across multiple switch nodes, making the overall system more manageable while enabling seamless roaming capabilities.
Solution Approach 2:
The patent introduces a new dimensional aspect to wireless network architecture by implementing full-mesh peering sessions between wireless switches across different IP subnets. This creates a multi-dimensional routing topology where control connections and data tunnels operate at the switch-to-switch level, enabling Layer 3 roaming without requiring changes to client devices.
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AI summary
Techniques and technologies are provided in which wireless switches, each supporting their own subnet, are configured as part of a mobility domain. Each wireless switch in the mobility domain can discover other wireless switches in the mobility domain upon joining the network, and establish a peering session with each of the other switches within the mobility domain. This can involve establishing a data tunnel, which operates according to GRE-over-IP, and a control connection between each pair of the wireless switches in the mobility domain. Each data tunnel carries complete Layer-2 (L2) packets between the first wireless switch and the second wireless switch. Each L2 packet comprises L2 header information (e.g., a VLAN identifier), and is made available at the destination wireless switch of the data tunnel. Each control connection comprises a peering session over Internet Protocol (IP) which operates according to the transmission control protocol (TCP). Each control connection is configured to transfer wireless client device mobility related control plane information between the first wireless switch and the second wireless switch. This architecture can allow a wireless client device to retain its layer 3 (L3) address when the wireless client device roams between wireless switches (e.g., the first wireless switch and the second wireless switch) which are part of the first mobility domain. As such, the wireless client device can maintains network layer connectivity when it roams within the first mobility domain.