Multi-Link Wi-Fi Roaming with Phased Context Transfer

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Solution Overview

Problem

Existing Wi-Fi networks face challenges in minimizing the adverse impact on data transfer and operation during the roaming process of Non-AP Multi-Link Devices (Non-AP MLDs) as transferring all context and reserving resources on target Access Point Multi-Link Devices (AP MLDs can add significant delays and network overhead.

Innovation Solution

A phased roaming procedure is implemented, where static context is transferred during a preparation phase and dynamic context during an execution phase, with enhancements for time-bound resource reservations to minimize data flow disruption during context transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all context is transferred and resources are reserved on target AP MLDs during roaming, then roaming reliability is improved, but roaming delay increases significantly

Engineering Contradiction:

Improveroaming reliabilityVSAvoidroaming delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The context transfer process is segmented into two distinct phases: a preparation phase where static context is transferred and resources are reserved, and an execution phase where dynamic context is transferred. This segmentation allows the system to prepare for roaming in advance without forcing all context transfer to complete before the actual roaming occurs, thereby reducing the critical path delay while ensuring reliability through preliminary setup.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Static context transfer and resource reservation are performed as preliminary actions during the preparation phase, before the actual roaming execution. By completing these tasks in advance, the system ensures that when roaming is triggered, the critical path involves only the dynamic context transfer, significantly reducing roaming delay while maintaining reliability through pre-established resources.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If context transfer is performed during roaming execution, then roaming delay is reduced, but data flow disruption increases

Engineering Contradiction:

Improveroaming delayVSAvoiddata flow disruption

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

Context transfer is segmented into static context (prepared in advance) and dynamic context (transferred during execution). This segmentation allows the system to minimize the time window for data flow disruption by only transferring essential dynamic context during the actual roaming execution, while static context is already in place from the preparation phase.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The preparation phase enables continuous useful action by pre-transferring static context and reserving resources, so that when roaming execution occurs, the data path can be switched with minimal interruption. The dynamic context transfer is quickly completed and the new data path is immediately activated, maintaining continuity of data flow with minimal disruption.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If resources are reserved on target AP MLDs, then roaming reliability is improved, but network overhead increases

Engineering Contradiction:

Improveroaming reliabilityVSAvoidnetwork overhead

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

Resource reservation is segmented into static resource reservation (performed in preparation phase) and dynamic resource allocation (performed during execution phase). This segmentation allows the system to reserve essential static resources in advance to ensure roaming reliability, while minimizing additional network overhead by only allocating dynamic resources when actually needed during roaming execution.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20260059408A1Roaming procedure for context transfer during roaming in a multi-link operation network

Publication Date: 2026.02.26 CISCO TECHNOLOGY INC

AI summary

In one aspect, a method includes initiating a roaming procedure for a Non-Access Point Multi-Link Device (Non-AP MLD) to roam from a current Access Point Multi-Link Device (AP MLD) onto a target AP MLD; determining whether a multi-phased roaming procedure for the Non-AP MLD to roam to the target AP MLD is possible; performing the multi-phased roaming procedure when the multi-phased roaming procedure is possible; and performing a single-phased roaming procedure when the multi-phased roaming procedure is not possible.