Wireless Controller Cluster State Information Management
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Solution Overview
Problem
Conventional WLAN architectures face scalability and redundancy issues due to inefficient management of state information across controllers, leading to network disruptions and resource wastage when client devices switch between access points managed by different controllers, especially across IP subnets or within the same subnet without proper communication mechanisms.
Innovation Solution
Implementing a cluster of controllers with equal functionalities and capabilities to communicate state information and manage client devices and access points, allowing for seamless roaming, load balancing, and redundancy, thereby maintaining state information consistency and optimizing network resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a GRE tunnel is created between controllers to maintain state information when client devices cross IP subnets, then state information is preserved, but network traffic path length increases and network resources are wasted
Solution Approach 1:
The patent introduces a cluster of controllers that act as intermediaries to share state information directly. When a client device roams between APs on different IP subnets, the new controller can obtain state information from the old controller through the cluster communication mechanism, eliminating the need for a GRE tunnel and reducing the network traffic path length.
Solution Approach 2:
The patent implements state information copying between controllers in the cluster. When a client device roams, the state information is copied from the original controller to the new controller through the cluster communication interface, allowing the new controller to manage the client device without requiring a GRE tunnel for state information transfer.
2Reliability
If a network-wide table is implemented to support tunneling between controllers, then state information can be maintained across controllers, but scalability deteriorates as the number of client devices and controllers increases
Solution Approach 1:
The patent segments the state information management by assigning it to specific controllers based on client device location. Each controller maintains state information for client devices currently associated with its managed APs, and the cluster communication interface enables selective information sharing only when needed for roaming scenarios, eliminating the need for a centralized network-wide table.
Solution Approach 2:
The patent introduces a new communication dimension within the controller cluster that operates independently of the existing GRE tunnel mechanism. This cluster communication interface provides a direct path for state information exchange between controllers, bypassing the need for network-wide tables and improving scalability.
3Productivity
If controllers do not communicate when client devices switch between APs in the same IP subnet, then resource overhead is reduced, but state information is lost and client sessions must be recreated
Solution Approach 1:
The patent establishes preliminary communication mechanisms between controllers in the cluster before client device roaming occurs. The cluster communication interface is pre-configured to enable state information exchange, allowing controllers to proactively share state information when a client device roams between APs in the same IP subnet, preventing connection disruptions without requiring extensive resource overhead.
4Adaptability or versatility
If blacklisting function is used to direct client devices to targeted APs, then client matching is achieved, but network disruptions occur when controllers cannot communicate across cluster boundaries
Solution Approach 1:
The patent merges the blacklisting function with the cluster communication interface. When a controller wants to direct a client device to a targeted AP managed by another controller in the cluster, it can communicate this intention through the cluster communication interface, which then coordinates with the target controller to ensure seamless client matching without connection disruptions.
Data Source
AI summary
According to one embodiment of the invention, a non-transitory computer readable medium for improving the scalability and redundancy of a wireless communications network. One embodiment of the non-transitory computer readable medium comprises instructions that configure a first controller, of a plurality of controllers, as a primary controller for maintaining data associated with each particular device of a plurality of devices, for each particular device of the plurality of devices, select a respective secondary controller, from the plurality of controllers, for maintaining data associated with that particular device based on a respective identifier associated with that particular device, subsequent to selecting the secondary controller for each particular device of the plurality of devices, detect an error associated with the first controller, and responsive to detecting the error associated with the first controller, establish the secondary controller selected for each particular device, based on the respective identifier, as the primary controller for that particular device.