Selective Key Caching for Wireless Roaming Latency
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Solution Overview
Problem
Current Wi-Fi networking technologies face delays in wireless client roaming due to excessive packet exchange during authentication key negotiation, especially in IEEE 802.1X based security systems, which degrades performance for delay-sensitive applications and cloud-based services.
Innovation Solution
Implement a method for selectively caching authentication keys at access points and cloud-based controllers, allowing for faster roaming by retrieving keys from local caches instead of authentication servers, reducing the number of communication interactions and eliminating the need for full IEEE 802.1X processes during transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full IEEE 802.1X authentication process is performed during every access point transition, then security authentication is ensured, but roaming speed deteriorates due to excessive packet exchange
Solution Approach 1:
The patent implements preliminary key caching during the initial authentication phase. When a wireless client first connects to an access point, the authentication key is obtained through the full IEEE 802.1X process and stored in a cache at both the access point and controller. This preliminary action allows subsequent roaming events to use the cached key without repeating the full authentication process, thus resolving the contradiction between security and roaming speed.
Solution Approach 2:
The patent creates copies of the authentication key and stores them in cache memory at the access point and controller. Instead of retrieving the original key through repeated authentication processes, the system uses these cached copies during roaming events. This copying mechanism maintains security while dramatically reducing the packet exchange required during transitions.
2Loss of time
If authentication keys are cached locally at access points, then roaming response time is improved, but key management complexity increases
Solution Approach 1:
The patent segments the key management functionality by implementing separate cache structures at different levels: access point cache and controller cache. Each component has its own cache with specific responsibilities - the access point cache handles immediate local lookups while the controller cache provides backup and centralized management. This segmentation reduces the complexity at each individual component while maintaining overall system efficiency.
Solution Approach 2:
The controller acts as an intermediary between multiple access points and the authentication server. It maintains a centralized cache that serves as a backup and coordination point for key management across the network. This intermediary structure simplifies the overall key management by providing a single point of coordination rather than requiring complex peer-to-peer key management between all access points.
3Adaptability or versatility
If cloud-based controllers are used, then network scalability is improved, but service performance deteriorates due to increased network travel time
Solution Approach 1:
The patent implements preliminary key caching at the cloud-based controller during the initial authentication phase. By storing authentication keys in the controller cache before roaming events occur, the system prepares in advance for future roaming operations. This preliminary action eliminates the need for real-time communication with remote authentication servers during roaming, thus maintaining service performance despite the use of cloud-based infrastructure.
Solution Approach 2:
The patent creates and stores copies of authentication keys at the cloud-based controller in cache memory. These cached copies enable the controller to respond to roaming requests locally without needing to communicate with remote authentication servers in real-time. This copying mechanism bridges the gap between cloud-based scalability and local response performance.
Data Source
AI summary
Authentication keys are selectively cached locally for faster roaming of wireless stations in a communication network. An attempt by a station to reassociate with an access point is detected. Responsive to identifying a key corresponding to the station as evidence of a previous association, the key is retrieved from the key cache without contracting a controller or an authentication server, for faster responses. At least one modified response frame is generated to include the identified key along with an approval of the association between the access point and the station. The at least one modified response is sent from the access point to the station. An attempt to roam to a station for a first time is detected responsive to a key cache miss at the access point. If the station has previously associated with an access point under purview of the controller, keys are located and sent back to the access point without contacting an authentication server as an improvement over IEEE 802.11r. The retrieved key can then be stored at the access point key cache for future use. An initial connection to the network is detected responsive to a key cache miss at the controller. In this case, authentication keys are retrieved from an authentication server.