WiFi Roaming Gateway Detection Using DHCP Offer Messages

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Solution Overview

Problem

WIFI roaming can cause network disconnection due to the inability of a device to transmit ARP messages to the correct gateway after switching access points, leading to disruptions in network connectivity.

Innovation Solution

The device sends a DHCP discovery message upon detecting a WIFI roaming event, receives a DHCP offer message, and determines the target gateway based on this message to maintain network communication, thereby avoiding disconnection by obtaining the correct gateway information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a terminal device switches from one access point to another access point during WIFI roaming, then the terminal device can maintain network connection and extend coverage range, but the device may lose track of the correct gateway causing network disconnection

Engineering Contradiction:
Improvenetwork coverage rangeVSAvoidnetwork connection stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing ARP probing before actual data transmission after roaming. The terminal device sends ARP request messages to detect whether the default gateway is reachable in the new network environment, and only switches to the new gateway if the probing succeeds, thus preventing premature network disconnection

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms through ARP probing results. The terminal device continuously monitors gateway reachability by sending ARP requests and analyzing responses. Based on the feedback from ARP probing (whether the gateway responds), the device dynamically adjusts its gateway selection, maintaining reliable network connection during roaming

Inventive Principle:
Principle #23Feedback

2Reliability

If the terminal device frequently performs DHCP procedures to obtain correct gateway information during roaming, then network connection reliability is improved, but network overhead and processing frequency increase

Engineering Contradiction:
Improvegateway information accuracyVSAvoidDHCP procedure frequency
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of gateway detection from the complete DHCP procedure. Instead of performing full DHCP exchange, the terminal device only performs ARP probing to detect gateway reachability, separating the critical gateway detection function from the broader DHCP process, thus reducing network overhead while maintaining reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by performing only the necessary ARP probing step rather than the complete DHCP procedure. The terminal device sends ARP requests to detect gateway reachability without undergoing full DHCP negotiation, performing just enough action to achieve gateway detection while minimizing network overhead and processing complexity

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4203561B1Communication method and apparatus, and storage medium
Publication Date: 2026.03.11 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP4203561B1 patent drawingFigure 1
  • EP4203561B1 patent drawingFigure 2
  • EP4203561B1 patent drawingFigure 3

AI summary

The present disclosure relates to the technical field of communication, in particular to a communication method and apparatus, and a storage medium. The method includes: sending a dynamic host configuration protocol (DHCP) discovery message in a network in response to a device triggering a wireless fidelity (WIFI) roaming event (S21); receiving a DHCP offer message which is for responding to the DHCP discovery message (S22; S44; S54; S64); determining a target gateway according to the DHCP offer message (S23; S45); and performing network communication through the target gateway (S24; S46; S57; S68).