Access Point Proxy ARP Handover Update
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Solution Overview
Problem
During wireless LAN handover, the MAC address table in network switchers is not updated promptly, leading to unsuccessful frame relay and ARP inconsistencies, as existing methods require unnecessary data frame transmission or rely on proxy ARP function activation after receiving an IP packet, causing network troubles.
Innovation Solution
An access point device generates a data frame with the wireless terminal's physical address as the source and a broadcast address as the destination, transmitted to the network switcher, enabling immediate update of connection information and allowing the proxy ARP function to be used effectively without waiting for an IP packet, thus preventing network issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the next access point device transmits a dummy data frame to update the MAC address table, then the connection information is updated, but unnecessary data frames are transmitted
Solution Approach 1:
The access point device performs preliminary action by transmitting an ARP request packet before normal data transmission to pre-update the MAC address table in the network switcher. This ensures that when data frames need to be transmitted, the switcher already has the correct MAC address routing information, eliminating the need for dummy data frames and preventing frame relay failures.
2Ease of operation
If the proxy ARP function waits to receive an IP packet from the wireless terminal device, then the function can be executed, but frame relay fails during handover
Solution Approach 1:
The access point device performs preliminary action by transmitting an ARP request packet immediately upon detecting a handover, before receiving any IP packets from the wireless terminal device. This allows the proxy ARP function to be activated and the MAC address table to be updated in advance, ensuring frame relay succeeds during the critical handover period.
3Adaptability or versatility
If the previous access point device continues to have the proxy ARP function after handover, then it can reply to ARP requests, but ARP inconsistency occurs
Solution Approach 1:
The access point device extracts and removes the proxy ARP function for a specific wireless terminal device after detecting that a handover has occurred. By taking out this function from the previous access point device's active functions, the system prevents ARP inconsistency while maintaining the ability to provide proxy ARP services through the new access point device.
4Stability of the object's composition
If the MAC address table is not updated immediately during handover, then the system operates normally, but frame relay to the wireless terminal device fails
Solution Approach 1:
The access point device performs preliminary action by transmitting an ARP request packet to the network switcher before normal data transmission resumes after handover. This preliminary ARP request updates the MAC address table in advance, ensuring that the switcher has current routing information and frame relay operations succeed without interruption.
Data Source
AI summary
In an access point device, a controller controls a wired interface communicating on wire with a network switcher accommodating access point devices and a wireless interface communicating wirelessly with a wireless terminal device located in its service area. Services are handed over between the access point devices responsively to the wireless terminal device moving. Access point devices before and after the handover of services are defined as a handover source and a hand over destination, respectively. A hand over at the hand over destination causes a data frame to be generated containing the MAC address of the wireless terminal device as a source address, a broadcast address as a destination address and address information of its own device. A table holds terminal connection information defining the relationship of the MAC address to the IP address of the wireless terminal device. The data frame is transmitted to the network switcher through the wired interface.