Split-Plane Access Point Failover via SMLT Trunking
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Solution Overview
Problem
In split-plane wireless network deployments, existing failover mechanisms for access points are slow, taking tens of seconds to switch over, which can disrupt customer data, and are vulnerable to intermittent trunk connections, leading to repeated failover attempts when the connection flaps.
Innovation Solution
Implementing a split multi-link trunking (SMLT) protocol for interswitch trunk communication between wireless switching planes, allowing rapid fault detection and forwarding path modification, with a wireless control point directing access points to failover to a secondary switching plane only when the primary is confirmed down, and avoiding failover when both planes report each other as failed, indicating a flapping trunk line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing failover mechanisms are used in split-plane deployments, then access points can switch over to backup switching planes, but the failover process takes tens of seconds causing customer data disruption
Solution Approach 1:
The patent implements preliminary action by pre-establishing peer relationships between access points and multiple switching planes, and pre-configuring failover logic in the wireless control point. When a failure is detected, the system immediately activates the pre-configured failover path without requiring time-consuming discovery or configuration steps, reducing failover time from tens of seconds to subsecond levels.
2Reliability
If existing failover mechanisms are used, then access points can detect switching plane failures, but they are vulnerable to intermittent trunk connections causing repeated failover attempts
Solution Approach 1:
The patent implements feedback mechanisms where the wireless control point continuously monitors peer relationship status between access points and switching planes. When failure conditions are detected, the system sends feedback messages to coordinate failover actions and prevent repeated failover attempts due to intermittent trunk connections, thereby stabilizing the network during transient issues.
3Loss of time
If rapid failover is implemented, then customer data disruption is reduced, but the system complexity increases due to split multi-line trunking protocol implementation
Solution Approach 1:
The patent applies segmentation by dividing the failover functionality into distinct components: the wireless control point handles peer relationship management and failover coordination, while access points handle local peer relationship maintenance. This segmentation allows rapid failover execution at the access point level without requiring complex centralized coordination, reducing overall system complexity despite enabling subsecond failover.
Data Source
AI summary
A method, system and computer readable medium for fast failover of an access point are described. A system can cause a failover of a first wireless access point when a wireless control point determines that a first wireless switching plane has failed through a platform link failure mechanism. The system can also prevent a failover of the first wireless access point or a second wireless access point when a message is received from both the first wireless switching plane and a second wireless switching plane indicating that the other wireless switching plane has failed.