Standby Controller State Synchronization for WLAN Reliability
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Solution Overview
Problem
Conventional Wireless Local Area Network (WLAN) architectures face scalability and redundancy issues due to inefficient resource management across multiple controllers, leading to network disruptions and resource wastage when client devices roam between access points managed by different controllers, and lack seamless communication among controllers for maintaining state information and multicast transmissions.
Innovation Solution
Implementing a cluster of controllers with equal functionalities and capabilities to manage access points and client devices, enabling communication among controllers for load balancing, client steering, and enhanced multicast proxy, ensuring seamless transitions and efficient resource distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a GRE tunnel is created between controllers to maintain state information during client roaming, then reliability is improved, but network traffic path length increases and network resources are wasted
Solution Approach 1:
The patent introduces a standby controller as an intermediary that maintains state information in advance. When the primary controller fails, the standby controller directly takes over without requiring GRE tunnel communication, thus eliminating the lengthy traffic path while maintaining reliability through pre-configured redundancy
2Reliability
If a GRE tunnel is created between controllers to maintain state information, then reliability is improved, but device complexity increases due to network-wide table requirements
Solution Approach 1:
The patent extracts the state information maintenance function from the primary controller and places it in a dedicated standby controller. This eliminates the need for complex network-wide tables across all controllers, reducing device complexity while maintaining reliability through focused redundancy
3Adaptability or versatility
If client matching is implemented through blacklisting function, then adaptability is improved, but network disruptions occur when controllers cannot communicate
Solution Approach 1:
The patent implements preliminary action by pre-configuring standby controllers with state information before failures occur. This allows seamless client steering and matching without network disruptions, as the standby controller is already prepared to take over immediately when needed
4Device complexity
If controllers operate independently without communication mechanisms, then device complexity is reduced, but state information is lost during client roaming
Solution Approach 1:
The patent uses copying by creating a standby controller that maintains a copy of the primary controller's state information. This allows independent operation of controllers while preserving state information through the standby copy, eliminating the need for complex communication infrastructure
Data Source
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Figure 2
Figure 3A~3B
AI summary
According to one embodiment of the invention, a non-transitory computer readable medium for handling the failure of a controller within a communications network is provided. One embodiment of the non-transitory computer readable medium comprises instructions that cause a secondary network device, controller 1000 to identify one or more multicast streams received by a primary network device, controller 900, and detect that the primary network device has failed; and responsive to detecting that the primary network device has failed, cause the secondary network device to subscribe to the multicast streams.